Pin the build runner to the release's new mesh-catalog head

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/asks.go

@@ -1,161 +0,0 @@
-package main
-
-import (
-	"context"
-	"sort"
-	"strings"
-	"sync"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/buildstep"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
-
-	"mesh-delivery-assigner/internal/assign"
-)
-
-// AssignerModule is the asker the assigner's compose asks name.
-const AssignerModule = "mesh-delivery-assigner"
-
-// composeAsks are the compose asks the assigner put on the Go build seat's check stream (novox/hq ADR 0482 clause 4,
-// issues 1622 and 1623), by what each composes: one ask per key, put once and followed by a watch of its step key until
-// it ends, which wakes a pass. No timer: an ask that waits in the stream waits (its backlog is the view's and the
-// watchman's to show). A restart forgets them and asks again; the build module keeps a composer built for a commit, so a
-// second ask builds nothing.
-type composeAsks struct {
-	ctx   context.Context
-	asker buildrun.Asker
-	wake  func()
-	logf  func(string, ...any)
-	now   func() time.Time
-
-	mu   sync.Mutex
-	asks map[string]*composeAsk
-}
-
-type composeAsk struct {
-	id     string
-	cancel context.CancelFunc
-	ran    *assign.Ran
-}
-
-func newComposeAsks(ctx context.Context, asker buildrun.Asker, wake func(), logf func(string, ...any)) *composeAsks {
-	return &composeAsks{ctx: ctx, asker: asker, wake: wake, logf: logf, now: time.Now, asks: map[string]*composeAsk{}}
-}
-
-// get is the end of the ask that composes key, or nil and its id while it runs. The first get of a key puts the ask.
-// A job its layout refuses ends at once, failed with why: never silent.
-func (a *composeAsks) get(key string, job delivery.ComposeJob) (*assign.Ran, string) {
-	a.mu.Lock()
-	defer a.mu.Unlock()
-	if k, ok := a.asks[key]; ok {
-		return k.ran, k.id
-	}
-	ask := delivery.StepAsk{ID: buildstep.NewID(), Kind: delivery.AskCheck, Language: delivery.AskGo, Asker: AssignerModule,
-		At: a.now(), Compose: &job}
-	ctx, cancel := context.WithCancel(a.ctx)
-	k := &composeAsk{id: ask.ID, cancel: cancel}
-	a.asks[key] = k
-	if err := a.asker.Put(ctx, ask); err != nil {
-		a.logf("the compose ask %s for %s could not be put: %v", ask.ID, key, err)
-		k.ran = &assign.Ran{State: delivery.StepFailed, Reason: "the compose ask could not be put on the Go build seat: " + err.Error()}
-		cancel()
-		return k.ran, k.id
-	}
-	go func() {
-		step, err := a.asker.Wait(ctx, ask)
-		if ctx.Err() != nil {
-			return
-		}
-		ran := assign.RanOf(step)
-		if err != nil {
-			ran = assign.Ran{State: delivery.StepFailed, Reason: "the compose ask's step could not be followed: " + err.Error()}
-		}
-		a.mu.Lock()
-		k.ran = &ran
-		a.mu.Unlock()
-		a.wake()
-	}()
-	return nil, k.id
-}
-
-// sweep forgets, and stops following, every ask whose key no pass asked for this time: a candidate gone or moved on.
-func (a *composeAsks) sweep(seen map[string]bool) {
-	a.mu.Lock()
-	defer a.mu.Unlock()
-	for key, k := range a.asks {
-		if !seen[key] {
-			k.cancel()
-			delete(a.asks, key)
-		}
-	}
-}
-
-// composeAtHead is the composition of a group with a mesh-sdk member: the composer at its head and at each reader's
-// mesh-sdk, asked of the Go build seat, and the verdict once every ask ended; until then the verdict waits, naming the
-// asks. The keys it used are marked in seen.
-func (p *passer) composeAtHead(ctx context.Context, m assign.Mesh, ch assign.Change, seen map[string]bool, began time.Time) delivery.CompositionVerdict {
-	waiting := func(words string) delivery.CompositionVerdict {
-		return delivery.CompositionVerdict{Group: ch.Group, Heads: ch.Heads, State: delivery.CompositionWaits, Words: words}
-	}
-	head, err := assign.HeadJob(m, ch)
-	if err != nil {
-		return delivery.CompositionVerdict{Group: ch.Group, Heads: ch.Heads, State: delivery.CompositionFail, SDK: "mesh-sdk " + ch.SDKHead,
-			Words: "the compose ask at the group's mesh-sdk head cannot be made: " + err.Error()}
-	}
-	var pending []string
-	key := "head." + ch.Group + "." + ch.Heads + "." + ch.SDKHead
-	seen[key] = true
-	headRan, id := p.asks.get(key, head)
-	if headRan == nil {
-		pending = append(pending, "mesh-sdk "+ch.SDKHead+" (ask "+id+")")
-	}
-	var readers []assign.Reader
-	var notJudged []string
-	for _, module := range sortedNames(assign.ReaderModules) {
-		repository := assign.ReaderModules[module]
-		var commits []string
-		member := false
-		if h := ch.Members[repository]; h != "" {
-			commits, member = []string{h}, true
-		} else {
-			commits = p.w.runningCommits(module)
-		}
-		if len(commits) == 0 {
-			notJudged = append(notJudged, "not judged whether "+module+" reads the group's manifests: the builder's log holds no done "+
-				"trunk build of it, and the group holds no member of "+repository)
-			continue
-		}
-		for _, commit := range commits {
-			job, err := assign.ReaderJob(ch, module, repository, commit)
-			if err != nil {
-				readers = append(readers, assign.Reader{Module: module, Commit: commit, Member: member,
-					Ran: assign.Ran{State: delivery.StepFailed, Reason: err.Error()}})
-				continue
-			}
-			rkey := "reader." + ch.Group + "." + ch.Heads + "." + module + "." + commit
-			seen[rkey] = true
-			ran, rid := p.asks.get(rkey, job)
-			if ran == nil {
-				pending = append(pending, module+" at "+commit+" (ask "+rid+")")
-				continue
-			}
-			readers = append(readers, assign.Reader{Module: module, Commit: commit, Member: member, Ran: *ran})
-		}
-	}
-	if len(pending) > 0 {
-		return waiting("composing on the Go build seat with the mesh-sdk of " + strings.Join(pending, ", "))
-	}
-	v := assign.FromComposer(m, ch, *headRan, readers, time.Since(began))
-	v.Warnings = append(v.Warnings, notJudged...)
-	return v
-}
-
-func sortedNames(m map[string]string) []string {
-	out := make([]string, 0, len(m))
-	for k := range m {
-		out = append(out, k)
-	}
-	sort.Strings(out)
-	return out
-}

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/compose_integration_test.go

@@ -1,179 +0,0 @@
-//go:build integration
-
-package main
-
-import (
-	"encoding/json"
-	"errors"
-	"strings"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/nats-io/nats.go/jetstream"
-
-	"git.novox.be/novox/mesh-sdk/go/composer"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-// holder is a test holder of the Go build seat: it takes every ask from the seat's check worker, as mesh-build-go does,
-// and answers a compose ask by running mesh-sdk's composer over the request filled from the indexer's manifests (the
-// linked composer standing for the one the build module builds at the asked commit), writing its step on its node's key.
-type holder struct {
-	mu   sync.Mutex
-	asks []delivery.StepAsk
-}
-
-func (h *holder) taken() []delivery.StepAsk {
-	h.mu.Lock()
-	defer h.mu.Unlock()
-	return append([]delivery.StepAsk(nil), h.asks...)
-}
-
-func (b *bed) hold(t *testing.T) *holder {
-	t.Helper()
-	seat, _ := delivery.AskStream(delivery.AskGo)
-	worker, _ := delivery.AskWorker(delivery.AskGo, delivery.AskCheck)
-	subject, _ := delivery.AskSubject(delivery.AskGo, delivery.AskCheck)
-	cons, err := b.js.CreateOrUpdateConsumer(b.ctx, seat, jetstream.ConsumerConfig{Durable: worker, FilterSubject: subject, AckPolicy: jetstream.AckExplicitPolicy})
-	if err != nil {
-		t.Fatal(err)
-	}
-	steps := b.buckets[delivery.StepsBucket(goBuildModule)]
-	h := &holder{}
-	cc, err := cons.Consume(func(m jetstream.Msg) {
-		a, err := delivery.DecodeStepAsk(m.Data())
-		if err != nil || a.Compose == nil {
-			t.Errorf("the seat was put an ask that is not a compose: %v %s", err, m.Data())
-			m.Ack()
-			return
-		}
-		h.mu.Lock()
-		h.asks = append(h.asks, a)
-		h.mu.Unlock()
-		req, err := composer.Decode(a.Compose.Request)
-		if err == nil {
-			err = composer.Fill(&req, func(digest string) ([]byte, error) {
-				key, _ := delivery.ManifestsKey(digest)
-				e, err := b.buckets[delivery.ManifestsBucket].Get(b.ctx, key)
-				if err != nil {
-					return nil, err
-				}
-				man, err := delivery.DecodeManifest(e.Value())
-				return []byte(man.JSON), err
-			})
-		}
-		step := delivery.Step{ID: a.ID, Tool: "compose", Node: "ace", State: delivery.StepPassed, Started: time.Now().UTC(), Ended: time.Now().UTC()}
-		if err != nil {
-			step.State, step.Reason = delivery.StepFailed, err.Error()
-		} else if v, err := composer.Run(req); err != nil {
-			step.State, step.Reason = delivery.StepFailed, err.Error()
-		} else {
-			vr, _ := json.Marshal(v)
-			step.Result, _ = json.Marshal(delivery.ComposeAnswer{Built: true, Key: "composer-0123456789abcdef", Verdict: vr})
-		}
-		raw, err := delivery.EncodeStep(step)
-		if err != nil {
-			t.Errorf("the step cannot be written: %v", err)
-		}
-		key, _ := delivery.AskStepKey("ace", a.ID)
-		if _, err := steps.Put(b.ctx, key, raw); err != nil {
-			t.Errorf("the step %s: %v", key, err)
-		}
-		m.Ack()
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(cc.Stop)
-	return h
-}
-
-// 1622/AC1-AC3 and 1623 on the bus: started whole, the assigner composes a group holding a mesh-sdk pull request by
-// asking the Go build seat for the composer at the member's head, and for the composer at the mesh-sdk the running
-// node-engine pins; it waits naming the asks while they run, writes the verdict from their answers naming the mesh-sdk the
-// head's composer was built with, and asks nothing more on a later pass of the same heads.
-func TestAGroupWithAnSDKMemberIsComposedByTheComposerAtItsHead(t *testing.T) {
-	b := startBed(t, "")
-	trunk := b.manifest(t, "web", `{"module":"web","version":"1"}`)
-	changed := b.manifest(t, "web", `{"module":"web","version":"2"}`)
-	mod, err := delivery.EncodeModule(delivery.Module{FP2: delivery.SourcePrefix2 + strings.Repeat("a", 64), Manifest: trunk, Repository: "novox/web", Commit: strings.Repeat("1", 40), Path: delivery.RootPath})
-	if err != nil {
-		t.Fatal(err)
-	}
-	b.putJSON(t, delivery.ModulesBucket, "web", mod)
-	b.place(t, "g14", "web")
-	running := strings.Repeat("3", 40)
-	b.place(t, "novox", "mesh-host")
-	b.built(t, "mesh-host", "novox/mesh-host", running)
-	sdkHead := strings.Repeat("4", 40)
-	heads := []delivery.Head{{Repository: "novox/mesh-sdk", Number: 80, Head: sdkHead}, {Repository: "novox/web", Number: 7, Head: strings.Repeat("2", 40)}}
-	hash, _ := delivery.HeadsHash(heads)
-	pulls := []delivery.CandidatePull{{Head: heads[0]}, {Head: heads[1],
-		Modules: []string{"web"}, Fps: map[string]delivery.CandidateModule{"web": {FP2: delivery.SourcePrefix2 + strings.Repeat("b", 64), Manifest: changed}}}}
-	cand, err := delivery.EncodeCandidate(delivery.Candidate{Group: "feat/x", HeadsHash: hash, Pulls: pulls, FPSet: delivery.FingerprintSet(pulls)})
-	if err != nil {
-		t.Fatal(err)
-	}
-	ckey, _ := delivery.CandidatesKey("feat/x")
-	b.putJSON(t, delivery.CandidatesBucket, ckey, cand)
-	b.start(t)
-	key, _ := delivery.CompositionKey("feat/x", hash)
-	// No holder takes the asks yet: the composition waits, naming them.
-	waits := b.verdict(t, key, func(v delivery.CompositionVerdict) bool { return v.State == delivery.CompositionWaits })
-	if !strings.Contains(waits.Words, "mesh-sdk "+sdkHead) || !strings.Contains(waits.Words, "mesh-host at "+running) {
-		t.Fatalf("the waiting composition says %q, want the head's and the running node-engine's asks", waits.Words)
-	}
-	h := b.hold(t)
-	v := b.verdict(t, key, func(v delivery.CompositionVerdict) bool { return v.State != delivery.CompositionWaits })
-	if v.State != delivery.CompositionPass || len(v.Machines) != 1 || v.Machines[0] != "g14" || v.SDK == "" {
-		t.Fatalf("composition = %+v, want a pass on g14", v)
-	}
-	asks := h.taken()
-	if len(asks) != 2 {
-		t.Fatalf("the seat was asked %d composes, want two (the head, the running node-engine)", len(asks))
-	}
-	byRepo := map[string]delivery.StepAsk{}
-	for _, a := range asks {
-		byRepo[a.Compose.Fetch["repository"].(string)] = a
-		if a.Asker != AssignerModule || a.Kind != delivery.AskCheck || a.Language != delivery.AskGo {
-			t.Errorf("ask = %+v", a)
-		}
-	}
-	if a := byRepo["novox/mesh-sdk"]; a.Compose == nil || a.Compose.Fetch["commit"] != sdkHead || a.Compose.Dir != "go" {
-		t.Errorf("the head's ask = %+v", a.Compose)
-	}
-	if a := byRepo["novox/mesh-host"]; a.Compose == nil || a.Compose.Fetch["commit"] != running || a.Compose.Dir != delivery.RootPath {
-		t.Errorf("the running node-engine's ask = %+v", a.Compose)
-	}
-	// A later pass of the same heads (woken by any change) asks nothing more.
-	on, _ := delivery.EncodePresence(delivery.Presence{Online: true})
-	b.putJSON(t, delivery.PresenceBucket, "ace", on)
-	time.Sleep(500 * time.Millisecond)
-	if n := len(h.taken()); n != 2 {
-		t.Errorf("a later pass of the same heads asked again: %d asks", n)
-	}
-}
-
-// verdict waits for the composition under key to satisfy ok, and answers it.
-func (b *bed) verdict(t *testing.T, key string, ok func(delivery.CompositionVerdict) bool) delivery.CompositionVerdict {
-	t.Helper()
-	var last delivery.CompositionVerdict
-	for deadline := time.Now().Add(10 * time.Second); time.Now().Before(deadline); time.Sleep(50 * time.Millisecond) {
-		e, err := b.buckets[delivery.AssignerCompositionsBucket].Get(b.ctx, key)
-		if errors.Is(err, jetstream.ErrKeyNotFound) {
-			continue
-		}
-		if err != nil {
-			t.Fatal(err)
-		}
-		if last, err = delivery.DecodeCompositionVerdict(e.Value()); err != nil {
-			t.Fatal(err)
-		}
-		if ok(last) {
-			return last
-		}
-	}
-	t.Fatalf("no composition under %s as wanted after 10 s; last %+v", key, last)
-	return last
-}

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/composed.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"sort"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// Every node's published compositions, read only to compare (novox/hq ADR 0593 §8): each node's engine writes its own
+// `composed-<node>` (delivery.ComposedRead, one bucket per node), and `mesh-wants.upgrade` with compare names, for every
+// node, the composition its own have runs beside the newest it published of each module and of the node, so a person sees
+// where they part. The assigner composes nothing and never writes these.
+
+// publishedRow is one composition a node published: the module ("node" for its own), the fingerprint, the digest, or why
+// it was refused or cannot be read.
+type publishedRow struct {
+	Key     string `json:"key"`
+	Module  string `json:"module"`
+	FP      string `json:"fp,omitempty"`
+	Digest  string `json:"digest,omitempty"`
+	Refused string `json:"refused,omitempty"`
+	Unread  string `json:"unread,omitempty"`
+}
+
+// published is, by node, every composition it published, sorted by key, from every key of the per-node state (a key
+// names its node first): each value decoded and digested here, as the node-engine digests it (delivery.ComposedDigestOf).
+// A value or key that does not read is named with why, never left out.
+func published(values map[string][]byte) map[string][]publishedRow {
+	byNode := map[string]map[string][]byte{}
+	for key, raw := range values {
+		node, _, _ := strings.Cut(key, ".")
+		if byNode[node] == nil {
+			byNode[node] = map[string][]byte{}
+		}
+		byNode[node][key] = raw
+	}
+	out := map[string][]publishedRow{}
+	for node, keys := range byNode {
+		var rows []publishedRow
+		for key, raw := range keys {
+			row := publishedRow{Key: key}
+			_, module, fp, isNode, err := delivery.ParseComposedKey(key)
+			switch {
+			case err != nil:
+				row.Unread = err.Error()
+			case isNode:
+				row.Module = "node"
+			default:
+				row.Module, row.FP = module, fp
+			}
+			if err == nil {
+				c, derr := delivery.DecodeComposed(raw)
+				switch {
+				case derr != nil:
+					row.Unread = derr.Error()
+				case c.Refused != "":
+					row.Refused = c.Refused
+				default:
+					if d, err := delivery.ComposedDigestOf(c); err != nil {
+						row.Unread = err.Error()
+					} else {
+						row.Digest = d
+					}
+				}
+			}
+			rows = append(rows, row)
+		}
+		sort.Slice(rows, func(i, j int) bool { return rows[i].Key < rows[j].Key })
+		out[node] = rows
+	}
+	return out
+}

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/integration_test.go

@@ -24,10 +24,10 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/asks"
 	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
-	"git.novox.be/novox/mesh-sdk/go/compose/judge"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/health"
 	"git.novox.be/novox/mesh-sdk/go/process"
+	"mesh-delivery-assigner/internal/judge"
 
 	"mesh-delivery-assigner/internal/assign"
 )
@@ -290,19 +290,6 @@ func (b *bed) place(t *testing.T, node, module string) {
 	}
 }
 
-// built appends the end of a done trunk build of module at commit to the builder's log, as the builder does.
-func (b *bed) built(t *testing.T, module, repository, commit string) {
-	t.Helper()
-	raw, err := delivery.EncodeBuildLogEntry(delivery.BuildLogEntry{Event: delivery.BuildEndedEvent, Module: module, FP: delivery.SourcePrefix2 + strings.Repeat("c", 64),
-		Repository: repository, Directory: delivery.RootPath, Commit: commit, Node: "novox", At: time.Now().UTC(), Outcome: delivery.BuildDone})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if _, err := b.js.Publish(b.ctx, buscompose.LogSubject(delivery.BuilderModule, delivery.BuilderLog)+"."+module, raw); err != nil {
-		t.Fatal(err)
-	}
-}
-
 // compose says the node's own composition is the digest d (a letter repeated), as its have names it (`<node>.node`): a
 // placed node composes its own (ADR 0571 §6), and the controller's composition is read no more. It answers the digest.
 func (b *bed) compose(t *testing.T, node string, d byte) string {
@@ -333,62 +320,6 @@ func (b *bed) manifest(t *testing.T, module, body string) string {
 	return digest
 }
 
-// 1297/AC1: against the real bus, a fixture change touching one module on one machine is composed and answered within
-// seconds under the checker's key of the check, naming the machine composed and the mesh-sdk it composed with.
-func TestAChangeIsComposedOnTheBus(t *testing.T) {
-	b := startBed(t, "")
-	trunk := b.manifest(t, "web", `{"module":"web","version":"1"}`)
-	changed := b.manifest(t, "web", `{"module":"web","version":"2"}`)
-	mod, err := delivery.EncodeModule(delivery.Module{FP2: delivery.SourcePrefix2 + strings.Repeat("a", 64), Manifest: trunk, Repository: "novox/web", Commit: strings.Repeat("1", 40), Path: delivery.RootPath})
-	if err != nil {
-		t.Fatal(err)
-	}
-	b.putJSON(t, delivery.ModulesBucket, "web", mod)
-	b.place(t, "g14", "web")
-	b.place(t, "ace", "other")
-	heads := []delivery.Head{{Repository: "novox/web", Number: 7, Head: strings.Repeat("2", 40)}}
-	hash, _ := delivery.HeadsHash(heads)
-	// 1927/AC1: the candidate carries the fingerprint set the SDK computes, as the indexer writes it.
-	pulls := []delivery.CandidatePull{{Head: heads[0],
-		Modules: []string{"web"}, Fps: map[string]delivery.CandidateModule{"web": {FP2: delivery.SourcePrefix2 + strings.Repeat("b", 64), Manifest: changed}}}}
-	cand, err := delivery.EncodeCandidate(delivery.Candidate{Group: "feat/x", HeadsHash: hash, Pulls: pulls, FPSet: delivery.FingerprintSet(pulls)})
-	if err != nil {
-		t.Fatal(err)
-	}
-	ckey, _ := delivery.CandidatesKey("feat/x")
-	b.putJSON(t, delivery.CandidatesBucket, ckey, cand)
-	began := time.Now()
-	b.start(t)
-	key, _ := delivery.CompositionKey("feat/x", hash)
-	var v delivery.CompositionVerdict
-	for deadline := time.Now().Add(10 * time.Second); ; time.Sleep(50 * time.Millisecond) {
-		if time.Now().After(deadline) {
-			t.Fatalf("no composition under %s after 10 s", key)
-		}
-		e, err := b.buckets[delivery.AssignerCompositionsBucket].Get(b.ctx, key)
-		if err != nil {
-			continue
-		}
-		if v, err = delivery.DecodeCompositionVerdict(e.Value()); err != nil {
-			t.Fatal(err)
-		}
-		break
-	}
-	if v.State != delivery.CompositionPass || len(v.Machines) != 1 || v.Machines[0] != "g14" || v.SDK == "" {
-		t.Fatalf("composition = %+v, want a pass on g14 alone naming its mesh-sdk", v)
-	}
-	if took := time.Since(began); took > 5*time.Second {
-		t.Errorf("the composition took %s", took)
-	}
-	// 1622/AC3: a group without a mesh-sdk member builds no composer: no ask is put on the Go build seat.
-	seat, _ := delivery.AskStream(delivery.AskGo)
-	if st, err := b.js.Stream(b.ctx, seat); err != nil {
-		t.Fatal(err)
-	} else if info, err := st.Info(b.ctx); err != nil || info.State.Msgs != 0 {
-		t.Errorf("a group without a mesh-sdk member put %d asks on the Go build seat (%v)", info.State.Msgs, err)
-	}
-}
-
 // get waits for a key of one of the bed's buckets and answers its value.
 func (b *bed) get(t *testing.T, bucket, key string) []byte {
 	t.Helper()
@@ -1121,16 +1052,17 @@ func TestAProposalIsAnsweredApprovedAndWritten(t *testing.T) {
 		t.Error("a declined proposal wrote its key")
 	}
 
-	// ADR 0567 §4: a node that does not answer fails the verdict once its pulse key's time to live ends, heard on the bus
-	// with no timer of the assigner's, naming it.
+	// ADR 0593 §8: a node that does not answer is named as giving no answer once its pulse key's time to live ends, heard on
+	// the bus with no timer of the assigner's, and the proposal is decided on the answers it has: asked, not failed.
 	q, err = verbs.doPropose(map[string]any{"why": "again", "changes": `[{"op":"take-off","node":"laptop","module":"web"}]`}, "op")
 	if err != nil {
 		t.Fatal(err)
 	}
 	silent := q.(proposed).Proposal
-	failed := proposalNow(silent.ID, "failed for a silent node", func(p delivery.PlacementProposal) bool { return p.State == delivery.ProposalFailed })
-	if failed.Verdict == nil || !strings.Contains(strings.Join(failed.Verdict.Fails, "; "), "laptop (offline) did not answer") {
-		t.Errorf("the silent node's verdict = %+v", failed.Verdict)
+	decided := proposalNow(silent.ID, "decided without its silent nodes", func(p delivery.PlacementProposal) bool { return p.State == delivery.ProposalAsked })
+	if decided.Verdict == nil || decided.Verdict.State != delivery.VerdictPass ||
+		!strings.Contains(strings.Join(decided.Verdict.Notes, "; "), "no answer from") || !strings.Contains(strings.Join(decided.Verdict.Notes, "; "), "laptop (offline)") {
+		t.Errorf("the silent node's verdict = %+v", decided.Verdict)
 	}
 
 	// 774/S59 (ADR 0587 §7): a joining node is written on the enrolment's warrant with no node to answer and no ask raised,

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main.go

@@ -15,19 +15,15 @@ import (
 	"os"
 	"os/signal"
 	"slices"
-	"sync/atomic"
 	"syscall"
 	"time"
 
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
-	stdio "git.novox.be/novox/mesh-sdk/go"
 	"git.novox.be/novox/mesh-sdk/go/announce"
 	"git.novox.be/novox/mesh-sdk/go/asks"
-	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/health"
 	"git.novox.be/novox/mesh-sdk/go/process"
 	"git.novox.be/novox/mesh-sdk/go/provisions"
@@ -56,31 +52,23 @@ func main() {
 // readBuckets are the buckets of other parts the assigner reads, each named in its manifest's reads (the manifest test
 // holds the two lists equal), so the controller's broker grants exactly these.
 var readBuckets = []string{
-	buscompose.ResolvedBucket,
 	delivery.PartGrantsBucket,
 	delivery.AnswersBucket,
 	delivery.BuilderBuildsBucket,
-	delivery.CandidatesBucket,
 	delivery.ManifestsBucket,
 	delivery.ModulesBucket,
 	delivery.PresenceBucket,
 	delivery.HaveBucket,
-	delivery.StepsBucket(goBuildModule),
 	provisions.ProvisionsBucket,
-	keptBucket,
 }
 
-// readLogs are the logs of other parts the assigner reads, each named in its manifest's reads: the builder's log, whose
-// newest done trunk build of a module names the commit a reader of the manifests runs at (novox/hq ADR 0571 clause 1).
-var readLogs = []string{delivery.BuildLogRead}
-
-// goBuildModule is the Go build module, which takes the assigner's compose asks on its seat's check stream and writes
-// their steps in its steps state (novox/hq ADR 0482 clause 4).
-const goBuildModule = "mesh-build-go"
+// readFamilies are the states kept one bucket per node the assigner reads, each named in its manifest's reads: every
+// node's compositions, which mesh-wants.upgrade compares (novox/hq ADR 0593 §8).
+var readFamilies = []string{delivery.ComposedRead}
 
 // ownBuckets are the assigner's own states, as its manifest declares them: the seat mesh-placement's three among them
 // (ADR 0567 §1), named after the assigner as every module state is.
-var ownBuckets = []string{delivery.AssignerAsksBucket, delivery.AssignerCompositionsBucket, delivery.AssignerDifferencesBucket,
+var ownBuckets = []string{delivery.AssignerAsksBucket, delivery.AssignerDifferencesBucket,
 	delivery.AssignerPutsBucket, delivery.AssignerWantsBucket, delivery.PlacementBucket, delivery.PlacementProposalsBucket,
 	delivery.PlacementCandidatesBucket, delivery.PlacementPulsesBucket, assign.FindingsBucket, assign.PoliciesBucket, delivery.SeatHoldersBucket}
 
@@ -90,7 +78,7 @@ var seatBuckets = []string{delivery.PlacementBucket, delivery.PlacementProposals
 	delivery.PlacementPulsesBucket}
 
 // keptStates is what the assigner keeps and who may read it (ADR 0495 §2-§3): its wants by the watchman and the view
-// (and the node agent from release 6), its differences by the view, its compositions by the checker, its asks by the view
+// (and the node agent from release 6), its differences by the view, its asks by the view
 // and the teller, its puts by whoever follows one (ADR 0546), and the seat mesh-placement's placement, proposals and
 // candidates by the node agents, the grants part, mesh-config and the view (ADR 0567 §9), and its placement by
 // the builder, the checker and the indexer, through mesh-sdk's toolchain gate (issue 774, ADR 0549 §3).
@@ -100,7 +88,6 @@ var keptStates = []announce.State{
 	{Name: delivery.PlacementCandidatesState, Readable: true},
 	{Name: delivery.PlacementPulsesState, Readable: true},
 	{Name: "asks", Readable: true},
-	{Name: "compositions", Readable: true},
 	{Name: "differences", Readable: true},
 	{Name: "puts", Readable: true},
 	{Name: "wants", Readable: true},
@@ -135,11 +122,6 @@ func open(ctx context.Context, js process.BucketOpener, logf func(string, ...any
 			logf("the bucket %s cannot be opened (%v): it is bound once the bus says it was made", name, err)
 			continue
 		}
-		if name == keptBucket && err != nil {
-			// mesh-config's held values (ADR 0565 §5): without them a composition lays none, said in the journal.
-			logf("the bucket %s cannot be opened (%v): no held value is laid on a composition until it is bound", name, err)
-			continue
-		}
 		if name == provisions.ProvisionsBucket && err != nil {
 			// The seat mesh-provisioner's state, with its own delivery (ADR 0570 §4): bound once the bus says it was made;
 			// until then no want waits for a provision, as before.
@@ -175,7 +157,7 @@ func open(ctx context.Context, js process.BucketOpener, logf func(string, ...any
 // states and those new with a delivery of their own, bound once made, and the two that choose the grants' source.
 func startsWithout(name string) bool {
 	switch name {
-	case delivery.SeatHoldersBucket, keptBucket, provisions.ProvisionsBucket, assign.PoliciesBucket, assign.FindingsBucket,
+	case delivery.SeatHoldersBucket, provisions.ProvisionsBucket, assign.PoliciesBucket, assign.FindingsBucket,
 		delivery.AssignerPutsBucket:
 		return true
 	}
@@ -211,10 +193,7 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	thisNode = account.Node
 	logger.Printf("started on the account %s, reading %d buckets", account.User, len(kvs))
 	findings := findingsOf(ctx, kvs, logger.Printf)
-	buildLog := func(handle func(stdio.LogEntry) error) error {
-		return said.ReadLog(delivery.BuilderModule, delivery.BuilderLog).Watch("", stdio.LogFromAll, handle)
-	}
-	return follow(ctx, js, conn, kvs, findings.Say(sayVia(ctx, js)), findings, emitting{said}, buildLog, logger)
+	return follow(ctx, js, conn, kvs, findings.Say(sayVia(ctx, js)), findings, emitting{said}, logger)
 }
 
 // findingsOf is where the assigner's said conditions go as findings (issue 1952 WM6): its findings bucket, which the
@@ -246,11 +225,9 @@ func (e emitting) Emit(eventType string, body any) error { return e.Conn.Emit(ev
 // watched are the buckets whose every value a pass reads; the manifests are read by digest when a pass needs one, and
 // watched only for keys, so a manifest that arrives wakes a composition that waits for it.
 var watched = []string{
-	buscompose.ResolvedBucket,
 	delivery.PartGrantsBucket,
 	delivery.AnswersBucket,
 	delivery.BuilderBuildsBucket,
-	delivery.CandidatesBucket,
 	delivery.ModulesBucket,
 	delivery.PlacementBucket,
 	delivery.PlacementProposalsBucket,
@@ -259,18 +236,16 @@ var watched = []string{
 	delivery.PresenceBucket,
 	delivery.HaveBucket,
 	delivery.AssignerAsksBucket,
-	delivery.AssignerCompositionsBucket,
 	delivery.AssignerDifferencesBucket,
 	delivery.AssignerWantsBucket,
 	assign.PoliciesBucket,
 	provisions.ProvisionsBucket,
-	keptBucket,
 	delivery.SeatHoldersBucket,
 }
 
 // follow watches every bucket a pass reads and makes a pass at start, once every watch handed what stands, and after
 // each change; changes that come during a pass make one more. It returns when ctx ends or a watch ends.
-func follow(ctx context.Context, js jetstream.JetStream, nc process.Subscriber, kvs buckets, say func(asks.Condition) error, findings assign.Findings, bus caller, buildLog logWatch, logger *log.Logger) error {
+func follow(ctx context.Context, js jetstream.JetStream, nc process.Subscriber, kvs buckets, say func(asks.Condition) error, findings assign.Findings, bus caller, logger *log.Logger) error {
 	w := newWorld()
 	dirty := make(chan struct{}, 1)
 	wake := func() {
@@ -279,22 +254,6 @@ func follow(ctx context.Context, js jetstream.JetStream, nc process.Subscriber,
 		default:
 		}
 	}
-	// The builder's log (ADR 0571 clause 1): every entry it keeps before the first pass, then each new one as it is appended;
-	// a module's newer done trunk build makes a pass, as a composition waiting on its commit is judged then. Where it cannot be
-	// read, a composition names no running reader of the manifests until the assigner starts again, and it is said.
-	if buildLog != nil {
-		var first atomic.Bool
-		if err := buildLog(func(le stdio.LogEntry) error {
-			if w.putBuilt(le.Value) && first.Load() {
-				wake()
-			}
-			return nil
-		}); err != nil {
-			logger.Printf("%s is not read (%v): no composition is judged against a running reader of the manifests until the assigner starts again",
-				delivery.BuildLogRead, err)
-		}
-		first.Store(true)
-	}
 	errs := make(chan error, len(watched)+2)
 	settled := make(chan struct{}, len(watched)+2)
 	watch := func(name string, opts ...jetstream.WatchOpt) error {
@@ -402,7 +361,7 @@ func follow(ctx context.Context, js jetstream.JetStream, nc process.Subscriber,
 		}
 	}
 	// And the two that choose where grants are read from, with the same delivery as the grants part that writes one.
-	for _, name := range []string{delivery.PartGrantsBucket, assign.PoliciesBucket, provisions.ProvisionsBucket, keptBucket, delivery.SeatHoldersBucket} {
+	for _, name := range []string{delivery.PartGrantsBucket, assign.PoliciesBucket, provisions.ProvisionsBucket, delivery.SeatHoldersBucket} {
 		if kvs[name] == nil && js != nil {
 			name := name
 			process.AwaitBucket(ctx, js, nc, name, "until then the bucket is not read",
@@ -427,7 +386,6 @@ func follow(ctx context.Context, js jetstream.JetStream, nc process.Subscriber,
 		}
 	}
 	p := &passer{kvs: kvs, w: w, logf: logger.Printf, say: say, findings: findings, said: map[string]bool{}, answeredAt: map[string]uint64{}}
-	p.asks = newComposeAsks(ctx, buildrun.Asker{Publisher: buildrun.JetStreamAsks{JS: js}, Waiter: buildrun.JetStreamAsks{JS: js}}, wake, logger.Printf)
 	if bus != nil && kvs[delivery.AssignerPutsBucket] != nil {
 		p.acts = newPutActs(bus, wake, logger.Printf)
 	}

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main_test.go

@@ -40,14 +40,14 @@ func TestOpensWhatItsManifestNames(t *testing.T) {
 	}
 	var reads []string
 	for _, r := range m.Reads {
-		if slices.Contains(readLogs, r) {
-			continue // a log, read through its own reader (ADR 0571 clause 1), not a bucket
+		if slices.Contains(readFamilies, r) {
+			continue // a state kept one bucket per node, read by its prefix (ADR 0593 §6), not one bucket
 		}
 		reads = append(reads, strings.Replace(r, ".", "_", 1))
 	}
-	for _, l := range readLogs {
+	for _, l := range readFamilies {
 		if !slices.Contains(m.Reads, l) {
-			t.Errorf("the program reads the log %s, the manifest does not name it", l)
+			t.Errorf("the program reads the per-node state %s, the manifest does not name it", l)
 		}
 	}
 	var states []string
@@ -113,7 +113,7 @@ func TestOpensWhatItsManifestNames(t *testing.T) {
 	}
 	kvs[delivery.AssignerPutsBucket].(*watchKV).closed = true
 	kvs[delivery.AssignerWantsBucket].(*watchKV).wrote = wrote
-	go follow(ctx, nil, nil, kvs, func(asks.Condition) error { return nil }, assign.Findings{}, nil, nil, log.New(io.Discard, "", 0))
+	go follow(ctx, nil, nil, kvs, func(asks.Condition) error { return nil }, assign.Findings{}, nil, log.New(io.Discard, "", 0))
 	select {
 	case key := <-wrote:
 		if key != "want.ace.node" {

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/pass.go

@@ -14,7 +14,6 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/provisions"
-	"git.novox.be/novox/mesh-sdk/go/sdkversion"
 
 	"mesh-delivery-assigner/internal/assign"
 )
@@ -40,7 +39,6 @@ type passer struct {
 	unplaced map[string]bool
 	// answeredAt is, by the id of a backup ask, how many values the have had when its answer was written into the want.
 	answeredAt map[string]uint64
-	asks       *composeAsks
 	// now is the clock; nil is time.Now.
 	now func() time.Time
 	// neither is, by node and module, each module on neither list whose condition this process raised (issue 1945). Nil until the
@@ -81,7 +79,6 @@ func (p *passer) clock() time.Time {
 
 func (p *passer) pass(ctx context.Context) {
 	p.placementSeat(ctx)
-	p.compositions(ctx)
 	p.wants(ctx)
 	p.puts(ctx)
 	p.nodeWants(ctx)
@@ -478,57 +475,6 @@ func (p *passer) sayNeither(now, stale map[string]neitherOne, left map[string]st
 	}
 }
 
-// compositions writes the composition check's verdict of every group the indexer holds a candidate for, under the
-// checker's key of that check: waits, with why, while the indexer holds what it composes from only in part.
-func (p *passer) compositions(ctx context.Context) {
-	if p.sdk == "" {
-		p.sdk = sdkversion.Version()
-	}
-	written := p.w.read(delivery.AssignerCompositionsBucket)
-	trunk := p.w.trunk()
-	var mesh *assign.Mesh
-	seen := map[string]bool{}
-	if p.asks != nil {
-		defer p.asks.sweep(seen)
-	}
-	for key, value := range p.w.read(delivery.CandidatesBucket) {
-		c, err := delivery.DecodeCandidate(value)
-		if err != nil {
-			p.logf("the candidate %s cannot be read, so it is not composed: %v", key, err)
-			continue
-		}
-		out, err := delivery.CompositionKey(c.Group, c.HeadsHash)
-		if err != nil {
-			p.logf("the candidate %s names no composition key: %v", key, err)
-			continue
-		}
-		began := time.Now()
-		ch, waits := p.w.change(ctx, kvGetter(p.kvs[delivery.ManifestsBucket]), c, trunk)
-		var v delivery.CompositionVerdict
-		if waits != "" {
-			v = delivery.CompositionVerdict{Group: c.Group, Heads: c.HeadsHash, State: delivery.CompositionWaits, Words: waits}
-		} else {
-			if mesh == nil {
-				m := p.w.mesh(ctx, kvGetter(p.kvs[delivery.ManifestsBucket]))
-				mesh = &m
-			}
-			if ch.SDKHead != "" && p.asks != nil {
-				// A group with a mesh-sdk member is composed by the composer built at its head (ADR 0482 clauses 3 to 5).
-				v = p.composeAtHead(ctx, *mesh, ch, seen, began)
-			} else {
-				v = assign.Compose(*mesh, ch, p.sdk, time.Since(began))
-			}
-		}
-		if before, err := delivery.DecodeCompositionVerdict(written[out]); err == nil {
-			before.Took, before.V = v.Took, 0
-			if delivery.SameCompositionVerdict(before, v) {
-				continue
-			}
-		}
-		p.put(ctx, delivery.AssignerCompositionsBucket, out, func() ([]byte, error) { return delivery.EncodeCompositionVerdict(v) })
-	}
-}
-
 // put writes one key of the assigner's own bucket; a write that fails is said and made again at the next pass.
 func (p *passer) put(ctx context.Context, bucket, key string, encode func() ([]byte, error)) {
 	value, err := encode()

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/pass_test.go

@@ -791,35 +791,18 @@ func TestARecordAskOfAHeldBackNodeSurvivesPassesAndItsYesMovesTheWant(t *testing
 }
 
 // 774/S26/AC1 (ADR 0549 §5, ADR 0567 §8): the seat's placement alone names where modules run: no controller state is read, so a
-// module in an assignment only is no module of its node; before any placement is read nothing is placed and the check composes
-// no input; placed, the check composes over the input the nodes compose from (frombus, 1126, ADR 0547 §2).
+// module in an assignment only is no module of its node, and before any placement is read nothing is placed.
 func aPlacementAloneNamesWhereModulesRun(t *testing.T) {
 	p := newPasser(buckets{}, time.Date(2026, 10, 26, 18, 0, 0, 0, time.UTC))
 	p.w.put("mesh-controller_assignments", "g14.b", []byte(`{"node":"g14","module":"b","build":"b-1"}`)) // read no more
 	if got := p.w.assigned(); len(got) != 0 {
 		t.Fatalf("before any placement: assigned %v", got)
 	}
-	none := func(context.Context, string) ([]byte, error) { return nil, errNotThere }
-	if m := p.w.mesh(context.Background(), none); m.Input != nil || m.InputUnread != "" {
-		t.Errorf("before any placement the check composes over %+v (%q)", m.Input, m.InputUnread)
-	}
 	placeOn(t, p.w, "g14", "c", "a")
 	placeOn(t, p.w, "n2", "d")
 	if got := p.w.assigned(); !slices.Equal(got["g14"], []string{"a", "c"}) || !slices.Equal(got["n2"], []string{"d"}) || len(got) != 2 {
 		t.Errorf("the placement alone: assigned %v", got)
 	}
-	if m := p.w.mesh(context.Background(), none); m.Input != nil || !strings.Contains(m.InputUnread, "g14") {
-		t.Errorf("a placed node with no record: input %+v, unread %q", m.Input, m.InputUnread)
-	}
-	placeOn(t, p.w, "g14", "a", "b", "c")
-	rec, _ := delivery.EncodeHaveNode(delivery.HaveNode{Record: &delivery.NodeRecord{Node: "g14", TunnelKey: "k"}})
-	p.w.put(delivery.HaveBucket, "g14.node", rec)
-	rec2, _ := delivery.EncodeHaveNode(delivery.HaveNode{Record: &delivery.NodeRecord{Node: "n2", TunnelKey: "k2"}})
-	p.w.put(delivery.HaveBucket, "n2.node", rec2)
-	m := p.w.mesh(context.Background(), none)
-	if m.Input == nil || len(m.Input.Nodes) != 2 || !slices.Equal(m.Input.Nodes[0].Assigned, []string{"a", "b", "c"}) || m.Input.Nodes[0].Place.Key != "k" {
-		t.Errorf("the check's input from the bus: %+v (%q)", m.Input, m.InputUnread)
-	}
 }
 
 // 1126 (ADR 0547 §2 to §4): a node the catalogue places composes its own: its wants name the build alone and its own want

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/seat.go

@@ -16,14 +16,12 @@ import (
 	"github.com/nats-io/nats.go/jetstream"
 
 	"git.novox.be/novox/mesh-sdk/go/asks"
-	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/compose/frombus"
-	"git.novox.be/novox/mesh-sdk/go/compose/judge"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/handacts"
 	"git.novox.be/novox/mesh-sdk/go/process"
 
 	"mesh-delivery-assigner/internal/assign"
+	"mesh-delivery-assigner/internal/judge"
 )
 
 // The seat mesh-placement's holder in the assigner's process (novox/hq ADR 0567 §2-§8): each pass follows every open
@@ -354,67 +352,35 @@ func moved(prop delivery.PlacementProposal, revs map[string]uint64) bool {
 	return false
 }
 
-// intended is, by proposal and the revisions it was laid over, what Intended computed, kept while this process runs.
+// intendedOf is, by proposal and the revisions it was laid over, what Intended computed, kept while this process runs.
 func (p *passer) intendedOf(prop delivery.PlacementProposal, current map[string]delivery.Placement, cands map[string]delivery.PlacementCandidate) map[string]map[string]bool {
 	key := fmt.Sprint(prop.ID, prop.Base)
 	if got, ok := p.intended[key]; ok {
 		return got
 	}
-	got, _, _ := p.compute(prop, current, cands)
+	got, _ := p.compute(prop, current, cands)
 	p.intended[key] = got
 	return got
 }
 
-// compute composes every node with the current placement and with the proposal laid over it (judge.Intended).
-func (p *passer) compute(prop delivery.PlacementProposal, current map[string]delivery.Placement, cands map[string]delivery.PlacementCandidate) (map[string]map[string]bool, []string, []string) {
+// compute is what the proposal changes on each node by its placement, and the nodes that answer it: every node with a
+// placement or a record (judge.Intended, ADR 0593 §8). The holder composes nothing: each node says what its compositions
+// change in its answer.
+func (p *passer) compute(prop delivery.PlacementProposal, current map[string]delivery.Placement, cands map[string]delivery.PlacementCandidate) (map[string]map[string]bool, []string) {
 	laid := map[string]*delivery.Placement{}
 	for _, node := range prop.Nodes() {
 		if c, ok := cands[node]; ok && !c.Reached {
 			laid[node] = c.Placement
 		}
 	}
-	get := kvGetter(p.kvs[delivery.ManifestsBucket])
-	r := worldReader{w: p.w, manifests: get}
-	// A read that fails is said, never dropped silently (novox/hq ADR 0578 §3); a refused manifest no longer fails it, and
-	// its module is held, named in the input's Refused.
-	var now, with *compose.Input
-	if in, err := frombus.Input(context.Background(), r, frombus.Mesh{}, frombus.Scope{Every: true}); err == nil {
-		now = &in
-	} else if p.logf != nil {
-		p.logf("proposal %s: the current composition input cannot be read, so what it changes is judged without it: %v", prop.ID, err)
-	}
-	if in, err := frombus.Input(context.Background(), r, frombus.Mesh{}, frombus.Scope{Every: true, Placements: laid}); err == nil {
-		with = &in
-	} else if p.logf != nil {
-		p.logf("proposal %s: the composition input with the proposal cannot be read, so what it changes is judged without it: %v", prop.ID, err)
-	}
-	if now != nil && len(now.Refused) > 0 && p.logf != nil {
-		var held []string
-		for _, m := range slices.Sorted(maps.Keys(now.Refused)) {
-			held = append(held, m+" ("+now.Refused[m]+")")
-		}
-		p.logf("proposal %s: held as refused by the indexer's judge: %s", prop.ID, strings.Join(held, "; "))
-	}
 	nodes := map[string]bool{}
 	for n := range current {
 		nodes[n] = true
 	}
-	if records, err := r.Records(context.Background()); err == nil {
-		for n := range records {
-			nodes[n] = true
-		}
+	for n := range p.w.records() {
+		nodes[n] = true
 	}
-	names := make([]string, 0, len(nodes))
-	for n := range nodes {
-		names = append(names, n)
-	}
-	fps := map[string]string{}
-	for name, m := range p.w.trunk() {
-		if m.FP2 != "" {
-			fps[name] = m.FP2
-		}
-	}
-	return judge.Intended(now, with, current, laid, names, fps)
+	return judge.Intended(current, laid, slices.Sorted(maps.Keys(nodes)))
 }
 
 // mustAnswer finds the nodes the proposal must hear from (§3), writes a reached candidate for each whose key it does not
@@ -425,7 +391,7 @@ func (p *passer) mustAnswer(ctx context.Context, prop delivery.PlacementProposal
 			return // the verbs write the candidates before the proposal: wait to hear them
 		}
 	}
-	intended, must, notes := p.compute(prop, current, cands)
+	intended, must := p.compute(prop, current, cands)
 	p.intended[fmt.Sprint(prop.ID, prop.Base)] = intended
 	for _, node := range must {
 		if _, ok := cands[node]; ok {
@@ -447,9 +413,6 @@ func (p *passer) mustAnswer(ctx context.Context, prop delivery.PlacementProposal
 		}
 	}
 	prop.Must = must
-	if len(notes) > 0 {
-		prop.Words = strings.TrimPrefix(prop.Words+"; "+strings.Join(notes, "; "), "; ")
-	}
 	p.writeProposal(ctx, prop, rev)
 }
 
@@ -483,7 +446,7 @@ func (p *passer) lays(ctx context.Context) (func(string) bool, func(string) bool
 			held[name] = true
 		}
 	}
-	records, _ := worldReader{w: p.w}.Records(ctx)
+	records := p.w.records()
 	return func(m string) bool { return held[m] }, func(n string) bool { _, ok := records[n]; return ok }
 }
 

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/seat_tools_test.go

@@ -367,9 +367,16 @@ func TestTheSeatsVerbs(t *testing.T) {
 func wantsVerbs(t *testing.T) {
 	fpOld, fpNew := delivery.SourcePrefix2+strings.Repeat("1", 64), delivery.SourcePrefix2+strings.Repeat("2", 64)
 	st := memStore{}
-	for _, state := range []string{modulesState, manifestsState, policiesState, haveState, putsState, "findings"} {
+	for _, state := range []string{modulesState, manifestsState, policiesState, haveState, putsState, "findings", delivery.ComposedRead} {
 		st[state] = &memKV{values: map[string][]byte{}}
 	}
+	// ADR 0593 §6, §8: what each node published, every node's bucket as one state: anchor's own composition and its web at
+	// a fingerprint, and laptop's web refused there.
+	webKey, _ := delivery.ComposedKey("anchor", "web", fpNew)
+	refusedKey, _ := delivery.ComposedKey("laptop", "web", fpNew)
+	st[delivery.ComposedRead].values["anchor.node"], _ = delivery.EncodeComposed(delivery.Composed{Node: "anchor"})
+	st[delivery.ComposedRead].values[webKey], _ = delivery.EncodeComposed(delivery.Composed{Node: "anchor", Module: "web", FP: fpNew})
+	st[delivery.ComposedRead].values[refusedKey], _ = delivery.EncodeComposed(delivery.Composed{Node: "laptop", Module: "web", FP: fpNew, Refused: "a required value is unset"})
 	manifest := func(name, extra string) {
 		raw := `{"module":"` + name + `","version":"1"` + extra + `}`
 		digest := delivery.ManifestDigest([]byte(raw))
@@ -409,6 +416,11 @@ func wantsVerbs(t *testing.T) {
 		got["composed"].(map[string]string)["anchor"] != "sha256:"+strings.Repeat("c", 64) || len(got["composed"].(map[string]string)) != 1 {
 		t.Errorf("compare = %+v", got)
 	}
+	pub, _ := out.(map[string]any)["published"].(map[string][]publishedRow)
+	if a, l := pub["anchor"], pub["laptop"]; len(a) != 2 || a[0].Module != "node" || a[1].Module != "web" || a[1].FP != fpNew ||
+		!strings.HasPrefix(a[1].Digest, "sha256:") || len(l) != 1 || l[0].Refused != "a required value is unset" || l[0].Digest != "" {
+		t.Errorf("published = %+v (unread %v)", pub, out.(map[string]any)["published-unread"])
+	}
 	// Read by watch (issue 1953 L5f): the same answer, each watched state started once, and no get per key of the
 	// large states (the modules, their manifests, the composed record).
 	watches := map[string]int{}

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/wants_tools.go

@@ -20,7 +20,7 @@ import (
 // The seat mesh-wants' verbs (novox/hq ADR 0565 §7, §8, §9, §15; issue 1953 D4-D6), served through the tool runner beside the
 // put tools and mesh-placement's verbs. `upgrade` reads and sets a person's upgrade policy, kept in the state `policies`
 // (each set recorded as a hand act and said as policy-changed), and with compare lists the digest of the composition each node's
-// own have names (the controller writes no policy any more, so no module's policy differs); `bus` says what a bus upgrade would do. The assigner's process reads
+// own have names beside every composition each node published (ADR 0593 §8, composed.go); `bus` says what a bus upgrade would do. The assigner's process reads
 // `policies` when it judges a move and writes the finding policy-split while a split stands.
 
 // The states the verbs read, as the runtime names them.
@@ -158,6 +158,12 @@ func (s *wantsTools) doUpgrade(args map[string]any, by string) (any, error) {
 			}
 		}
 		out := map[string]any{"composed": composed}
+		// And what every node published (ADR 0593 §8), read only to compare.
+		if values, err := s.values(delivery.ComposedRead); err != nil {
+			out["published-unread"] = err.Error()
+		} else {
+			out["published"] = published(values)
+		}
 		// The assigner's findings, its said conditions as the condition keeper reads them (§15).
 		if found, err := s.values(health.FindingsState); err != nil {
 			out["findings-unread"] = err.Error()

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/world.go

@@ -3,20 +3,14 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"slices"
 	"sort"
-	"strings"
 	"sync"
 	"time"
 
 	"github.com/nats-io/nats.go/jetstream"
 
-	stdio "git.novox.be/novox/mesh-sdk/go"
-	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
-	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/compose/frombus"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 
 	"mesh-delivery-assigner/internal/assign"
@@ -249,63 +243,11 @@ func (w *world) trunk() map[string]delivery.Module {
 	return out
 }
 
-// mesh is the mesh as the trunk holds it, for the composition check.
-func (w *world) mesh(ctx context.Context, manifests getter) assign.Mesh {
-	m := assign.Mesh{Manifests: map[string]catalogue.Manifest{}, Unreadable: map[string]string{}, Digests: map[string]string{}}
-	m.Assigned = w.assigned()
-	for name, mod := range w.trunk() {
-		if mod.Manifest == "" {
-			continue
-		}
-		m.Digests[name] = mod.Manifest
-		// The indexer's verdict on it, carried in its value (ADR 0578 §3, §5): a refused module is held and named as one
-		// that cannot be read, and its verdict goes into the composer's input.
-		if v := mod.VerdictOf(name); v != nil {
-			if refused, _ := delivery.TakeManifestVerdict(v); refused {
-				if m.Verdicts == nil {
-					m.Verdicts = map[string]delivery.ManifestVerdict{}
-				}
-				m.Verdicts[name] = *v
-				m.Unreadable[name] = v.Why()
-				continue
-			}
-		}
-		p := w.manifest(ctx, manifests, mod.Manifest)
-		if p.err != "" {
-			m.Unreadable[name] = p.err
-			continue
-		}
-		m.Manifests[name] = p.manifest
-	}
-	// Once the catalogue places the nodes, the check composes over the input they compose from (ADR 0547 §2, ADR 0549
-	// §3): one composer's input for the check and the nodes. An input that cannot be read is said, and the nodes and their
-	// assignments alone are composed, as before any placement.
-	if _, seeded := w.placed(); seeded {
-		in, err := frombus.Input(ctx, worldReader{w: w, manifests: manifests}, frombus.Mesh{}, frombus.Scope{Every: true})
-		if err != nil {
-			m.InputUnread = err.Error()
-		} else {
-			m.Input = &in
-		}
-	}
-	return m
-}
-
-// worldReader is what the assigner watched as frombus reads the bus: the seat's placement, the indexer's modules, each node's
-// record in its own have key, the manifests by digest; the check reads no config value, own secret or credential (the
-// composition it asks resolves, and stands in for what it does not carry).
-type worldReader struct {
-	w         *world
-	manifests getter
-}
-
-func (r worldReader) Placements(context.Context) (map[string]delivery.Placement, error) {
-	return r.w.placements(), nil
-}
-
-func (r worldReader) Records(context.Context) (map[string]delivery.NodeRecord, error) {
+// records is each node's record in its own have key (`<node>.node`): the nodes a placement proposal is answered by,
+// with those placement names (ADR 0593 §8).
+func (w *world) records() map[string]delivery.NodeRecord {
 	out := map[string]delivery.NodeRecord{}
-	for key, value := range r.w.read(delivery.HaveBucket) {
+	for key, value := range w.read(delivery.HaveBucket) {
 		node, _, isNode, err := delivery.ParseHaveKey(key)
 		if err != nil || !isNode {
 			continue
@@ -314,136 +256,7 @@ func (r worldReader) Records(context.Context) (map[string]delivery.NodeRecord, e
 			out[node] = *h.Record
 		}
 	}
-	return out, nil
-}
-
-func (r worldReader) Modules(context.Context) (map[string]delivery.Module, error) {
-	return r.w.trunk(), nil
-}
-
-func (r worldReader) Manifest(ctx context.Context, digest string) ([]byte, error) {
-	key, err := delivery.ManifestsKey(digest)
-	if err != nil {
-		return nil, err
-	}
-	raw, err := r.manifests(ctx, key)
-	if err != nil {
-		return nil, err
-	}
-	m, err := delivery.DecodeManifest(raw)
-	if err != nil {
-		return nil, err
-	}
-	return []byte(m.JSON), nil
-}
-
-// Values is one module's config values on one node as mesh-config resolved them, each a value its source lays
-// (catalogue.LaidValue): the holder composes every node a proposal touches with them (ADR 0567 §9).
-func (r worldReader) Values(_ context.Context, node, module string) (map[string]any, error) {
-	var out map[string]any
-	prefix := node + "." + module + "."
-	for key, raw := range r.w.read(buscompose.ResolvedBucket) {
-		name, ok := strings.CutPrefix(key, prefix)
-		if !ok || strings.Contains(name, ".") {
-			continue
-		}
-		if v, laid := catalogue.LaidValue(raw); laid {
-			if out == nil {
-				out = map[string]any{}
-			}
-			out[name] = v
-		}
-	}
-	return out, nil
-}
-
-func (worldReader) OwnSecrets(context.Context, string) ([]compose.OwnSecretRow, error) {
-	return nil, nil
-}
-
-func (worldReader) Credentials(context.Context, string, []compose.CredentialKey, []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
-	return nil, nil, nil
-}
-
-// Build and Archive are read only for a node composing itself (frombus.Scope without Every): the check of every node
-// composes from the manifests the indexer read, and reads no build and no archive.
-func (worldReader) Build(context.Context, string, string) (*delivery.BuilderBuild, error) {
-	return nil, nil
-}
-
-func (worldReader) Archive(_ context.Context, url, _ string) ([]byte, error) {
-	return nil, fmt.Errorf("the composition check reads no archive (%s)", url)
-}
-
-func (r worldReader) Served(ctx context.Context, node, module string, keys []string) (map[string]any, error) {
-	all, err := r.Values(ctx, node, module)
-	var out map[string]any
-	for _, k := range keys {
-		if v, ok := all[k]; ok {
-			if out == nil {
-				out = map[string]any{}
-			}
-			out[k] = v
-		}
-	}
-	return out, err
-}
-
-// change is a candidate's change for the composition check, or why the composition waits for it.
-func (w *world) change(ctx context.Context, manifests getter, c delivery.Candidate, trunk map[string]delivery.Module) (assign.Change, string) {
-	ch := assign.Change{Group: c.Group, Heads: c.HeadsHash, Manifests: map[string]catalogue.Manifest{}, Unreadable: map[string]string{},
-		Twice: map[string][]string{}, Digests: map[string]string{}, Members: map[string]string{}}
-	heads := map[string]string{}
-	for _, p := range c.Pulls {
-		heads[fmt.Sprintf("%s#%d", p.Repository, p.Number)] = p.Head.Head
-	}
-	ch.Held = assign.HeldOf(w.read(keptBucket), heads)
-	definedIn := map[string]map[string]bool{}
-	for _, p := range c.Pulls {
-		if p.Repository == assign.SDKRepository {
-			ch.SDKHead = p.Head.Head
-		}
-		ch.Members[p.Repository] = p.Head.Head
-		for _, name := range p.Modules {
-			fp, ok := p.Fps[name]
-			if !ok || fp.Manifest == "" {
-				if ok && fp.None2 == noModuleWords {
-					ch.Removed = append(ch.Removed, name)
-					continue
-				}
-				return ch, fmt.Sprintf("the indexer holds no manifest of %s for %s#%d yet", name, p.Repository, p.Number)
-			}
-			if fp.FP2 != "" && fp.FP2 != trunk[name].FP2 {
-				ch.Rebuilt++
-			}
-			got := w.manifest(ctx, manifests, fp.Manifest)
-			if strings.HasPrefix(got.err, "the indexer holds no manifest") {
-				return ch, got.err
-			}
-			ch.Digests[name] = fp.Manifest
-			if got.err != "" {
-				ch.Unreadable[name] = got.err
-				continue
-			}
-			ch.Manifests[got.module] = got.manifest
-			if definedIn[got.module] == nil {
-				definedIn[got.module] = map[string]bool{}
-			}
-			definedIn[got.module][p.Repository] = true
-			if t, ok := trunk[got.module]; ok && t.Repository != "" && t.Repository != p.Repository {
-				definedIn[got.module][t.Repository] = true
-			}
-		}
-	}
-	for name, repos := range definedIn {
-		if len(repos) > 1 {
-			for r := range repos {
-				ch.Twice[name] = append(ch.Twice[name], r)
-			}
-			sort.Strings(ch.Twice[name])
-		}
-	}
-	return ch, ""
+	return out
 }
 
 // online is, by node, whether the watchman holds the node online.
@@ -594,40 +407,6 @@ func (w *world) changed(bucket, key string) uint64 {
 	return w.changes[bucket+"|"+key]
 }
 
-// logWatch follows the builder's log: handle each entry it keeps, then each new one (process.LogReader.Watch).
-type logWatch func(handle func(stdio.LogEntry) error) error
-
-// putBuilt takes one entry of the builder's log in: a done trunk build's end (no ref) naming a full commit, newer than the
-// module's last, becomes the module's running commit. It answers whether the commit changed.
-func (w *world) putBuilt(raw []byte) bool {
-	e, err := delivery.DecodeBuildLogEntry(raw)
-	if err != nil || e.Event != delivery.BuildEndedEvent || e.Outcome != delivery.BuildDone || e.Ref != "" || len(e.Commit) != 40 {
-		return false
-	}
-	w.mu.Lock()
-	defer w.mu.Unlock()
-	have, ok := w.trunkBuilt[e.Module]
-	if ok && !e.At.After(have.At) {
-		return false
-	}
-	w.trunkBuilt[e.Module] = e
-	return !ok || have.Commit != e.Commit
-}
-
-// runningCommits is the commit of module's newest done trunk build in the builder's log (ADR 0571 clause 1): the commit a
-// reader of the manifests runs at (novox/hq ADR 0482 clause 5, issue 1623); none when the log holds no such build.
-func (w *world) runningCommits(module string) []string {
-	w.mu.Lock()
-	defer w.mu.Unlock()
-	if e, ok := w.trunkBuilt[module]; ok {
-		return []string{e.Commit}
-	}
-	return nil
-}
-
-// keptBucket is mesh-config's `kept`: the approved held values of open pull requests (ADR 0565 §5).
-var keptBucket = "mesh-config_" + delivery.MeshConfigKeptState
-
 // ownComposed is a placed node's own composition, as the digest its own have names (`<node>.node` of the haves, Composed):
 // what rule 7 reads. A node whose have names none is not composed yet.
 func (w *world) ownComposed(node string) (delivery.ComposedDigest, bool) {

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/world_test.go

@@ -2,15 +2,12 @@ package main
 
 import (
 	"context"
-	"os"
 	"slices"
 	"strings"
 	"testing"
 	"time"
 
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-
-	"mesh-delivery-assigner/internal/assign"
 )
 
 // fakeManifests is the indexer's manifests bucket in memory.
@@ -45,76 +42,6 @@ func pull(repo string, number int, modules map[string]delivery.CandidateModule)
 	return p
 }
 
-// 1297/B3b: a candidate's change reads each module's manifest by its digest, counts the modules rebuilt, takes a
-// module with no manifest in the preview as removed, a mesh-sdk member's head, and a module the trunk holds from
-// another repository as defined twice.
-func TestTheChangeOfACandidate(t *testing.T) {
-	theWorldCountsTheValuesAKeyTakes(t)
-	f := fakeManifests{}
-	web := f.add(t, "web", `{"module":"web","version":"2"}`)
-	mail := f.add(t, "mail", `{"module":"mail","version":"1"}`)
-	trunk := map[string]delivery.Module{"web": {FP2: fp('a'), Repository: "novox/web"}, "mail": {FP2: fp('c'), Repository: "novox/mail"}}
-	c := delivery.Candidate{Group: "g", HeadsHash: "0123456789ab", Pulls: []delivery.CandidatePull{
-		pull("novox/web", 1, map[string]delivery.CandidateModule{"web": {FP2: fp('b'), Manifest: web}, "old": {None2: noModuleWords}}),
-		pull("novox/other", 2, map[string]delivery.CandidateModule{"mail": {FP2: fp('c'), Manifest: mail}}),
-		pull(assign.SDKRepository, 3, nil),
-	}}
-	ch, waits := newWorld().change(context.Background(), f.get, c, trunk)
-	if waits != "" {
-		t.Fatalf("the change waits: %s", waits)
-	}
-	if ch.Manifests["web"].Version != "2" || ch.Rebuilt != 1 || !slices.Equal(ch.Removed, []string{"old"}) || ch.SDKHead != strings.Repeat("3", 40) {
-		t.Errorf("change = %+v", ch)
-	}
-	if !slices.Equal(ch.Twice["mail"], []string{"novox/mail", "novox/other"}) || len(ch.Twice) != 1 {
-		t.Errorf("twice = %v, want mail in novox/mail and novox/other", ch.Twice)
-	}
-}
-
-// 1297/B3b: a candidate whose module has no manifest digest yet, or whose manifest the indexer does not hold yet, waits,
-// saying for what; a manifest that does not decode is the change's, not a wait (one with a field the assigner does not
-// know is decoded with it set aside, novox/hq ADR 0578 §6).
-func TestAChangeWaitsForItsManifests(t *testing.T) {
-	f := fakeManifests{}
-	bad := f.add(t, "web", `{"module":"web","version":"2","requires":"x"}`)
-	for _, c := range []delivery.CandidatePull{
-		pull("novox/web", 1, map[string]delivery.CandidateModule{"web": {None2: "no preview yet"}}),
-		pull("novox/web", 1, map[string]delivery.CandidateModule{"web": {FP2: fp('b'), Manifest: strings.Repeat("9", 64)}}),
-	} {
-		_, waits := newWorld().change(context.Background(), f.get, delivery.Candidate{Group: "g", HeadsHash: "0123456789ab", Pulls: []delivery.CandidatePull{c}}, nil)
-		if waits == "" {
-			t.Errorf("a change without its manifest %+v does not wait", c.Fps)
-		}
-	}
-	ch, waits := newWorld().change(context.Background(), f.get, delivery.Candidate{Group: "g", HeadsHash: "0123456789ab",
-		Pulls: []delivery.CandidatePull{pull("novox/web", 1, map[string]delivery.CandidateModule{"web": {FP2: fp('b'), Manifest: bad}})}}, nil)
-	if waits != "" || ch.Unreadable["web"] == "" {
-		t.Errorf("an unreadable manifest: waits %q, change %+v", waits, ch)
-	}
-}
-
-// A manifest of the change whose config value falls back to a predefined key (novox/hq ADR 0348 §7) is read, not
-// unreadable for the catalogue's predefined.json the assigner never holds: the merge gate judges the fallback in the
-// catalogue, and the indexer reads it the same way (catalogue.ParseManifestForInputs, issue 1751). A group whose
-// mesh-catalog member touched pacman and xterm failed its composition on this (group check 18df81380db3). The manifest is
-// xterm's module.json from mesh-catalog at 835bf22b.
-func TestAManifestFallingBackToAPredefinedKeyIsReadable(t *testing.T) {
-	raw, err := os.ReadFile("testdata/catalogue-835bf22b-xterm.module.json")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !strings.Contains(string(raw), `"predefined"`) {
-		t.Fatal("the fixture names no predefined key")
-	}
-	f := fakeManifests{}
-	xterm := f.add(t, "xterm", string(raw))
-	ch, waits := newWorld().change(context.Background(), f.get, delivery.Candidate{Group: "g", HeadsHash: "0123456789ab",
-		Pulls: []delivery.CandidatePull{pull("novox/mesh-catalog", 1, map[string]delivery.CandidateModule{"xterm": {FP2: fp('b'), Manifest: xterm}})}}, nil)
-	if waits != "" || ch.Unreadable["xterm"] != "" || ch.Manifests["xterm"].Module != "xterm" {
-		t.Errorf("xterm: waits %q, unreadable %q, want read", waits, ch.Unreadable["xterm"])
-	}
-}
-
 // Review round 1 (items 3 and 4): the world counts the values a key takes, so a have written again after an answer is seen.
 func theWorldCountsTheValuesAKeyTakes(t *testing.T) {
 	w := newWorld()

modules/mesh-delivery-assigner/go.mod

@@ -3,7 +3,7 @@ module mesh-delivery-assigner
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )

modules/mesh-delivery-assigner/go.sum

@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791 h1:7SYIDPMxbPBr8dMB6k9fYsgVt4ZyWVL41q4LMFsfAvs=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128 h1:aI1DhZAuqVBXbybSqhLNOGX5rUOrn9T0cHNCDUQF7IQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=

modules/mesh-delivery-assigner/internal/assign/compose.go

@@ -1,368 +0,0 @@
-// Package assign is the assigner's judgement, as functions over what it read from the bus: the composition check of a
-// change (novox/hq ADR 0446 clauses 1 to 5, ADR 0528 clause 5, issue 1297), the six rules of what each node should
-// run (ADR 0429 §6, ADR 0528 clause 3) and the comparison with what the controller sends (ADR 0528 clause 4). It reads
-// and writes nothing itself: the program hands it what it watched and writes what it answers.
-package assign
-
-import (
-	"encoding/json"
-	"fmt"
-	"slices"
-	"sort"
-	"strings"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/catalogue"
-	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-// SDKRepository is the repository of mesh-sdk: a group with a member there changes the composition itself.
-const SDKRepository = "novox/mesh-sdk"
-
-// NotJudged names, in a composition's warnings, the failures of ADR 0446 clause 1 the assigner cannot judge from the
-// bus, because what they need is only in the controller's facts snapshot, which is not on the bus yet (issue 1461;
-// the design limit of R4g, issue 1297): said on every verdict, never passed silently.
-const NotJudged = "not judged until the facts snapshot is on the bus (issue 1461): a consumer left out of a grant, a " +
-	"credential left bound elsewhere, a stored setting the changed definition cannot keep, and a new module the " +
-	"node-engine's validator would refuse"
-
-// Mesh is the mesh as the trunk holds it: every module's manifest by name, the manifests that cannot be read with
-// why, and each node's open assignments.
-type Mesh struct {
-	Manifests  map[string]catalogue.Manifest
-	Unreadable map[string]string
-	Assigned   map[string][]string
-	// Digests is every trunk module's manifest digest in the indexer's manifests bucket, readable or not: what a
-	// composer at another mesh-sdk reads (issue 1622).
-	Digests map[string]string
-	// Input is the rest of the mesh as the nodes compose from it, filled by mesh-sdk's frombus from the catalogue's
-	// placement and the nodes' records (novox/hq ADR 0547 §2, ADR 0549 §3, issue 1126), so the check and the nodes share
-	// one composer's input; nil before any placement is read, when the nodes and their assignments alone are composed.
-	Input *compose.Input
-	// InputUnread says why that input could not be read from the bus, when it could not: the check then composes the
-	// nodes and their assignments alone, and says so in its warnings.
-	InputUnread string
-	// Verdicts are the indexer's refusals of trunk manifests, by module, as their values carry them (novox/hq ADR 0578
-	// §3): each such module is in Unreadable too, and the composer's input carries the verdict (§5).
-	Verdicts map[string]delivery.ManifestVerdict
-}
-
-// Change is a group's change as the indexer's candidate holds it: the manifest of every module it moves or adds, those
-// it cannot read and why, the modules it removes, every module defined twice with where, the heads of a mesh-sdk
-// member (empty when none), and how many modules it rebuilds.
-type Change struct {
-	Group, Heads string
-	Manifests    map[string]catalogue.Manifest
-	Unreadable   map[string]string
-	Removed      []string
-	Twice        map[string][]string
-	SDKHead      string
-	Rebuilt      int
-	// Digests is the manifest digest of every module the change moves or adds, readable by the assigner or not, and
-	// Members the head of each member by repository: what a composer at the group's mesh-sdk reads (issues 1622, 1623).
-	Digests map[string]string
-	Members map[string]string
-	// Held are the approved held values of the group's pull requests at the heads judged (mesh-config's `kept`, novox/hq ADR
-	// 0565 §5, ADR 0502 §4): each laid over its module's values on its node in the change's composition, and named.
-	Held []delivery.KeptValue
-}
-
-// HeldOf are the held values kept for the pull requests the candidate names, each at the head it names: one of another
-// pull request, or at another head, is never laid (ADR 0502 §4). kept is mesh-config's `kept` by key.
-func HeldOf(kept map[string][]byte, heads map[string]string) []delivery.KeptValue {
-	var out []delivery.KeptValue
-	for _, raw := range kept {
-		var k delivery.KeptValue
-		if json.Unmarshal(raw, &k) != nil || k.Node == "" || k.Module == "" || k.Key == "" {
-			continue
-		}
-		if head, ok := heads[k.Pull]; ok && head == k.Head {
-			out = append(out, k)
-		}
-	}
-	sort.Slice(out, func(i, j int) bool {
-		a, b := out[i], out[j]
-		return a.Pull+a.Node+a.Module+a.Key < b.Pull+b.Node+b.Module+b.Key
-	})
-	return out
-}
-
-// layHeld lays each held value over its module's values on its node, as a layer of its own after the rest, and answers
-// the words that name each; judged first against the head's declaration of its key (catalogue.ValueProblems), a value the
-// declaration refuses, or a key it does not declare, is a failure.
-func layHeld(in *compose.Input, held []delivery.KeptValue) (said, fails []string) {
-	for _, k := range held {
-		var v any
-		if err := json.Unmarshal(k.Value, &v); err != nil {
-			said = append(said, fmt.Sprintf("the held value %s of %s on %s for %s cannot be read, so it is not laid: %v", k.Key, k.Module, k.Node, k.Pull, err))
-			continue
-		}
-		d, declared := in.Catalogue[k.Module].Settings[k.Key]
-		if !declared {
-			fails = append(fails, fmt.Sprintf("the held value %s of %s on %s for %s: the head declares no such key", k.Key, k.Module, k.Node, k.Pull))
-			continue
-		}
-		if problems := catalogue.ValueProblems(d, v); len(problems) > 0 {
-			fails = append(fails, fmt.Sprintf("the held value %s of %s on %s for %s does not hold to the head's declaration: %s", k.Key, k.Module,
-				k.Node, k.Pull, strings.Join(problems, "; ")))
-			continue
-		}
-		at := slices.IndexFunc(in.Nodes, func(n compose.Node) bool { return n.Name == k.Node })
-		if at < 0 {
-			said = append(said, fmt.Sprintf("the held value %s of %s for %s names %s, which runs no module of the mesh: not laid", k.Key, k.Module, k.Pull, k.Node))
-			continue
-		}
-		if in.Nodes[at].Settings == nil {
-			in.Nodes[at].Settings = map[string][]catalogue.Layer{}
-		}
-		in.Nodes[at].Settings[k.Module] = append(in.Nodes[at].Settings[k.Module], catalogue.Layer{From: "held for " + k.Pull, Values: map[string]any{k.Key: v}})
-		said = append(said, fmt.Sprintf("held value laid: %s of %s on %s, held for %s at %.12s, approved by %s (novox/hq ADR 0502 §4)", k.Key, k.Module, k.Node, k.Pull, k.Head, k.Approved))
-	}
-	return said, fails
-}
-
-// Touched is the machines a change touches (ADR 0446 clause 3): those running a module the change moves, adds or
-// removes, those running a consumer of a provision such a module provides (before or after), and those running a
-// provider of a provision such a module requires after the change. A module the change adds that is assigned nowhere
-// touches no machine. A change of placement is no change of a repository (ADR 0567 §4): the seat
-// mesh-placement judges it.
-func Touched(m Mesh, c Change) []string {
-	moved := map[string]bool{}
-	for name := range c.Manifests {
-		moved[name] = true
-	}
-	for name := range c.Unreadable {
-		moved[name] = true
-	}
-	for _, name := range c.Removed {
-		moved[name] = true
-	}
-	provided, required := map[string]bool{}, map[string]bool{}
-	for name := range moved {
-		for _, man := range []catalogue.Manifest{m.Manifests[name], c.Manifests[name]} {
-			for _, o := range man.Provides {
-				provided[o.Name] = true
-			}
-		}
-		for _, r := range c.Manifests[name].Requires {
-			required[r] = true
-		}
-	}
-	var out []string
-	for node, modules := range m.Assigned {
-		for _, mod := range modules {
-			man := m.Manifests[mod]
-			if moved[mod] || slices.ContainsFunc(man.Requires, func(r string) bool { return provided[r] }) ||
-				slices.ContainsFunc(man.Provides, func(o catalogue.Offer) bool { return required[o.Name] }) {
-				out = append(out, node)
-				break
-			}
-		}
-	}
-	sort.Strings(out)
-	return out
-}
-
-// input is the composition's input for the mesh's catalogue and assignments: the nodes by name with what is assigned
-// to them, and every seat the assigned modules claim as held there. What the bus does not carry (places on the
-// private network, settings, credentials, licences) is left empty, so a trunk composition and a change's are made
-// with the same gaps and compared (ADR 0446 clause 1: what was already broken is said and fails nothing).
-func input(catalog map[string]catalogue.Manifest, assigned map[string][]string) compose.Input {
-	in := compose.Input{Catalogue: catalog}
-	nodes := make([]string, 0, len(assigned))
-	for n := range assigned {
-		nodes = append(nodes, n)
-	}
-	sort.Strings(nodes)
-	for _, n := range nodes {
-		in.Nodes = append(in.Nodes, compose.Node{Name: n, Assigned: slices.Clone(assigned[n])})
-		for _, mod := range assigned[n] {
-			for _, cl := range catalog[mod].Claims {
-				scope := cl.Scope
-				if seat, ok := catalogue.SeatNamed(cl.Name); ok && scope == "" {
-					scope = seat.Scope
-				}
-				in.Holdings = append(in.Holdings, catalogue.Held{Claim: cl.Name, Scope: scope, Node: n, Module: mod})
-			}
-		}
-	}
-	return in
-}
-
-// Compose is the composition check of change c over the mesh m, composed with the mesh-sdk version sdk: every touched
-// machine resolved as the trunk holds it and as the change leaves it. It fails on a manifest of the change that cannot
-// be read, a module a machine runs that the change removes, a module defined twice, and a machine that resolves on the
-// trunk and not with the change; a machine that does not resolve on either is said and fails nothing. It warns past
-// CompositionRebuildWarning modules rebuilt, says what it does not judge (NotJudged), and for a group with a mesh-sdk
-// member says it composed with its own mesh-sdk, not the member's head (issue 1621). took is how long it took.
-func Compose(m Mesh, c Change, sdk string, took time.Duration) delivery.CompositionVerdict {
-	v := delivery.CompositionVerdict{Group: c.Group, Heads: c.Heads, SDK: sdk, Took: took.Milliseconds()}
-	var fails []string
-	failAt := func(machine, words string) {
-		if v.Machine == "" && machine != "" {
-			v.Machine = machine
-		}
-		fails = append(fails, words)
-	}
-	for _, name := range sortedKeys(c.Unreadable) {
-		failAt("", fmt.Sprintf("the manifest of %s cannot be read: %s", name, c.Unreadable[name]))
-	}
-	for _, name := range sortedKeys(c.Twice) {
-		failAt("", fmt.Sprintf("%s is defined twice, in %s", name, strings.Join(c.Twice[name], " and ")))
-	}
-	machines := Touched(m, c)
-	v.Machines = machines
-	for _, node := range machines {
-		for _, name := range c.Removed {
-			if slices.Contains(m.Assigned[node], name) {
-				failAt(node, fmt.Sprintf("%s runs %s, which the change removes from its source", node, name))
-			}
-		}
-	}
-	trunk := input(m.Manifests, m.Assigned)
-	changed := map[string]catalogue.Manifest{}
-	for name, man := range m.Manifests {
-		changed[name] = man
-	}
-	for name, man := range c.Manifests {
-		changed[name] = man
-	}
-	for _, name := range c.Removed {
-		delete(changed, name)
-	}
-	after := input(changed, m.Assigned)
-	laid, heldFails := layHeld(&after, c.Held)
-	v.Warnings = append(v.Warnings, laid...)
-	for _, f := range heldFails {
-		failAt("", f)
-	}
-	for _, node := range machines {
-		_, before := compose.Resolve(trunk, node)
-		_, now := compose.Resolve(after, node)
-		switch {
-		case now == nil:
-		case before != nil:
-			v.Warnings = append(v.Warnings, fmt.Sprintf("%s does not compose on the trunk either, so the change is not blamed: %v", node, before))
-		default:
-			failAt(node, fmt.Sprintf("%s composes on the trunk and not with the change: %v", node, now))
-		}
-	}
-	if c.SDKHead != "" {
-		v.Warnings = append(v.Warnings, fmt.Sprintf("composed with the assigner's own mesh-sdk %s, not the group's mesh-sdk head %s, "+
-			"and a field the running controller cannot read is not judged (issues 1621, 1622, 1623)", sdk, c.SDKHead))
-	}
-	return finish(v, m, c, machines, fails)
-}
-
-// finish adds what every composition says beside its own judgement (more modules rebuilt than CompositionRebuildWarning,
-// what is not judged, the machines not composed, a change that touches none) and its state from fails.
-func finish(v delivery.CompositionVerdict, m Mesh, c Change, machines []string, fails []string) delivery.CompositionVerdict {
-	if c.Rebuilt > delivery.CompositionRebuildWarning {
-		v.Warnings = append(v.Warnings, fmt.Sprintf("the merge rebuilds %d modules, more than %d", c.Rebuilt, delivery.CompositionRebuildWarning))
-	}
-	v.Warnings = append(v.Warnings, NotJudged)
-	if could := CouldRun(m, c, machines); len(could) > 0 {
-		v.Warnings = append(v.Warnings, "not judged until the facts snapshot is on the bus (issue 1461, ADR 0537 clause 1): "+
-			"the machines that could run a moved or added module and are not assigned it: "+strings.Join(could, ", "))
-	}
-	if grants := GrantsAlone(m, c, machines); len(grants) > 0 {
-		v.Warnings = append(v.Warnings, "not judged until the facts snapshot is on the bus (issue 1461, ADR 0537 clause 1): "+
-			"the machines whose grants alone the change alters: "+strings.Join(grants, ", "))
-	}
-	if len(machines) == 0 {
-		v.Warnings = append(v.Warnings, "the change touches no machine: no module it moves is assigned anywhere")
-	}
-	if len(fails) > 0 {
-		v.State, v.Words = delivery.CompositionFail, strings.Join(fails, "; ")
-		return v
-	}
-	v.State = delivery.CompositionPass
-	return v
-}
-
-// CouldRun is, by name, every machine of the mesh not composed that is not assigned a module the change moves or adds
-// (ADR 0537 clause 1): which of them could run it, the bus does not say (capabilities, settings and places are only in
-// the facts snapshot), so each is named as not judged.
-func CouldRun(m Mesh, c Change, composed []string) []string {
-	var out []string
-	for node, modules := range m.Assigned {
-		if slices.Contains(composed, node) {
-			continue
-		}
-		for name := range c.Manifests {
-			if !slices.Contains(modules, name) {
-				out = append(out, node)
-				break
-			}
-		}
-	}
-	sort.Strings(out)
-	return out
-}
-
-// grantsOf is what of a manifest makes grants: its bus declarations and the provisions it requires and offers.
-func grantsOf(man catalogue.Manifest) string {
-	var offers []string
-	for _, o := range man.Provides {
-		offers = append(offers, o.Name)
-	}
-	return fmt.Sprint(man.Requires, offers, man.Reads, man.State, man.Emits, man.Consumes, man.Invokes, man.Claims, man.Grants)
-}
-
-// GrantsAlone is, by name, every machine not composed whose grants alone the change alters (ADR 0537 clause 1): for a
-// moved module whose grants differ from the trunk's, the machines assigned the bus's holder (whose user list carries
-// every module's bus grants) and those assigned a provider of a provision it requires, before or after.
-func GrantsAlone(m Mesh, c Change, composed []string) []string {
-	provisions := map[string]bool{}
-	altered := false
-	for name, man := range c.Manifests {
-		before, had := m.Manifests[name]
-		if had && grantsOf(before) == grantsOf(man) {
-			continue
-		}
-		altered = true
-		for _, r := range append(slices.Clone(man.Requires), before.Requires...) {
-			provisions[r] = true
-		}
-	}
-	if !altered {
-		return nil
-	}
-	var out []string
-	for node, modules := range m.Assigned {
-		if slices.Contains(composed, node) {
-			continue
-		}
-		for _, mod := range modules {
-			man := m.Manifests[mod]
-			if man.ClaimsSeat("mesh-broker") || slices.ContainsFunc(man.Provides, func(o catalogue.Offer) bool { return provisions[o.Name] }) {
-				out = append(out, node)
-				break
-			}
-		}
-	}
-	sort.Strings(out)
-	return out
-}
-
-// withOverlay is base with every manifest of over laid over it, a copy.
-func withOverlay(base, over map[string]catalogue.Manifest) map[string]catalogue.Manifest {
-	out := make(map[string]catalogue.Manifest, len(base)+len(over))
-	for name, man := range base {
-		out[name] = man
-	}
-	for name, man := range over {
-		out[name] = man
-	}
-	return out
-}
-
-func sortedKeys[V any](m map[string]V) []string {
-	out := make([]string, 0, len(m))
-	for k := range m {
-		out = append(out, k)
-	}
-	sort.Strings(out)
-	return out
-}

modules/mesh-delivery-assigner/internal/assign/compose_test.go

@@ -1,169 +0,0 @@
-package assign
-
-import (
-	"encoding/json"
-	"slices"
-	"strconv"
-	"strings"
-	"testing"
-
-	"git.novox.be/novox/mesh-sdk/go/catalogue"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-func meshOf() Mesh {
-	return Mesh{
-		Manifests: map[string]catalogue.Manifest{
-			"mail":  {Module: "mail", Version: "1", Requires: []string{"database"}},
-			"store": {Module: "store", Version: "1", Provides: []catalogue.Offer{{Name: "database"}}},
-			"web":   {Module: "web", Version: "1"},
-		},
-		Assigned: map[string][]string{"ace": {"mail", "store"}, "g14": {"web"}},
-	}
-}
-
-func hasWarning(v delivery.CompositionVerdict, part string) bool {
-	return slices.ContainsFunc(v.Warnings, func(w string) bool { return strings.Contains(w, part) })
-}
-
-// 1297/AC1 (its unit half): a change touching one module on one machine composes that machine alone, passes, names
-// the machine and the mesh-sdk it composed with, and says what it did not judge.
-func TestAChangeOfOneModuleComposesItsMachine(t *testing.T) {
-	c := Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"web": {Module: "web", Version: "2"}}}
-	v := Compose(meshOf(), c, "v0.1.14-x", 0)
-	if v.State != delivery.CompositionPass || !slices.Equal(v.Machines, []string{"g14"}) || v.SDK != "v0.1.14-x" {
-		t.Fatalf("composition = %+v, want a pass on g14 alone", v)
-	}
-	if !hasWarning(v, "issue 1461") {
-		t.Errorf("the verdict does not say what it did not judge: %v", v.Warnings)
-	}
-	if _, err := delivery.EncodeCompositionVerdict(v); err != nil {
-		t.Errorf("the verdict cannot be written: %v", err)
-	}
-	// 1953/D7 (ADR 0565 §5, ADR 0502 §4): the group's own pull request's held value at its head is laid and named, judged
-	// against the head's declaration; one of another pull request or another head is not laid.
-	web, err := catalogue.Decode([]byte(`{"module":"web","version":"2","config":{"port":{"type":"number","default":80,"description":"the port, a number","runtime":true}}}`))
-	if err != nil {
-		t.Fatal(err)
-	}
-	kept := map[string][]byte{}
-	for i, k := range []delivery.KeptValue{
-		{Pull: "novox/x#1", Head: "h1", Node: "g14", Module: "web", Key: "port", Value: json.RawMessage(`81`), Approved: "op"},
-		{Pull: "novox/x#2", Head: "h2", Node: "g14", Module: "web", Key: "port", Value: json.RawMessage(`82`)},
-		{Pull: "novox/x#1", Head: "old", Node: "g14", Module: "web", Key: "other", Value: json.RawMessage(`1`)},
-	} {
-		kept[strconv.Itoa(i)], _ = json.Marshal(k)
-	}
-	held := HeldOf(kept, map[string]string{"novox/x#1": "h1"})
-	if len(held) != 1 || string(held[0].Value) != "81" {
-		t.Fatalf("held = %+v, want #1's at its head alone", held)
-	}
-	c = Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"web": web}, Held: held}
-	if v := Compose(meshOf(), c, "x", 0); v.State != delivery.CompositionPass || !hasWarning(v, "held value laid: port of web on g14, held for novox/x#1") {
-		t.Errorf("composition = %+v", v)
-	}
-	c.Held[0].Value = json.RawMessage(`"eighty"`)
-	if v := Compose(meshOf(), c, "x", 0); v.State != delivery.CompositionFail || !strings.Contains(v.Words, "does not hold to the head's declaration") {
-		t.Errorf("a held value the declaration refuses: %+v", v)
-	}
-}
-
-// 1297/AC2 and B3c: a change that removes a module a machine runs fails, naming the machine and the module; a machine that
-// composes on the trunk and not with the change fails it, naming the machine and why (the consumer's machine is touched when
-// its provider changes); what was already broken on the trunk is said and fails nothing. One table (three tests merged).
-func TestAChangeThatBreaksAMachineFailsAndWhatWasBrokenFailsNothing(t *testing.T) {
-	broken := meshOf()
-	broken.Manifests["store"] = catalogue.Manifest{Module: "store", Version: "1"}
-	for _, c := range []struct {
-		name  string
-		mesh  Mesh
-		c     Change
-		state string
-		must  func(delivery.CompositionVerdict) bool
-	}{
-		{"removing a module a machine runs", meshOf(), Change{Group: "g", Heads: "0123456789ab", Removed: []string{"web"}}, delivery.CompositionFail,
-			func(v delivery.CompositionVerdict) bool {
-				return v.Machine == "g14" && strings.Contains(v.Words, "g14 runs web")
-			}},
-		{"a machine the change breaks", meshOf(), Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"store": {Module: "store", Version: "2"}}},
-			delivery.CompositionFail, func(v delivery.CompositionVerdict) bool {
-				return v.Machine == "ace" && strings.Contains(v.Words, "database")
-			}},
-		{"what was broken before", broken, Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"mail": {Module: "mail", Version: "2", Requires: []string{"database"}}}},
-			delivery.CompositionPass, func(v delivery.CompositionVerdict) bool { return hasWarning(v, "on the trunk either") }},
-	} {
-		if v := Compose(c.mesh, c.c, "sdk", 0); v.State != c.state || !c.must(v) {
-			t.Errorf("%s: composition = %+v", c.name, v)
-		}
-	}
-}
-
-// 1297/B3c: an unreadable manifest and a module defined twice fail; more than twelve rebuilt modules warn.
-func TestUnreadableTwiceAndWide(t *testing.T) {
-	c := Change{Group: "g", Heads: "0123456789ab", Unreadable: map[string]string{"web": "unknown field \"scope\""}, Rebuilt: 13}
-	v := Compose(meshOf(), c, "sdk", 0)
-	if v.State != delivery.CompositionFail || !strings.Contains(v.Words, "web cannot be read") || !hasWarning(v, "rebuilds 13 modules") {
-		t.Fatalf("composition = %+v", v)
-	}
-	c = Change{Group: "g", Heads: "0123456789ab", Twice: map[string][]string{"web": {"novox/a", "novox/b"}}, Rebuilt: 12}
-	v = Compose(meshOf(), c, "sdk", 0)
-	if v.State != delivery.CompositionFail || !strings.Contains(v.Words, "web is defined twice") || hasWarning(v, "rebuilds") {
-		t.Fatalf("composition = %+v", v)
-	}
-}
-
-// 1622's criterion as R4g delivers it: a group with a mesh-sdk member is composed with the assigner's own mesh-sdk, and
-// the verdict says so, naming the member's head it did not use; a group without one says nothing of it.
-func TestAGroupWithAnSDKMemberSaysWhichSDKComposedIt(t *testing.T) {
-	c := Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"web": {Module: "web", Version: "2"}}, SDKHead: "f625d98713e4"}
-	v := Compose(meshOf(), c, "v0.1.14-own", 0)
-	if !hasWarning(v, "not the group's mesh-sdk head f625d98713e4") || !hasWarning(v, "v0.1.14-own") || !hasWarning(v, "1623") {
-		t.Errorf("the verdict does not say it composed with its own mesh-sdk: %v", v.Warnings)
-	}
-	c.SDKHead = ""
-	if v := Compose(meshOf(), c, "v0.1.14-own", 0); hasWarning(v, "mesh-sdk head") {
-		t.Errorf("a group without a mesh-sdk member says it has one: %v", v.Warnings)
-	}
-}
-
-// 1297/B3a: the machines touched are those running a moved module or a consumer of what it provides; an added module
-// assigned nowhere touches none, and the verdict says so.
-func TestTouched(t *testing.T) {
-	m := meshOf()
-	if got := Touched(m, Change{Manifests: map[string]catalogue.Manifest{"store": m.Manifests["store"]}}); !slices.Equal(got, []string{"ace"}) {
-		t.Errorf("touched by store = %v", got)
-	}
-	m.Assigned["g14"] = append(m.Assigned["g14"], "mail")
-	if got := Touched(m, Change{Manifests: map[string]catalogue.Manifest{"store": m.Manifests["store"]}}); !slices.Equal(got, []string{"ace", "g14"}) {
-		t.Errorf("touched by store with a consumer on g14 = %v", got)
-	}
-	c := Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{"new": {Module: "new", Version: "1"}}}
-	if v := Compose(m, c, "sdk", 0); len(v.Machines) != 0 || !hasWarning(v, "touches no machine") || v.State != delivery.CompositionPass {
-		t.Errorf("an added module assigned nowhere: %+v", v)
-	}
-}
-
-// ADR 0537 clause 1: every verdict names, by machine, those that could run a moved or added module and are not assigned
-// it, and those whose grants alone the change alters (the bus's machine, a provider of what the module requires), as not
-// judged; shanks, providing what web now requires, is composed and so named in neither. A change that alters no grant
-// names none of the second.
-func TestTheMachinesNotJudgedAreNamed(t *testing.T) {
-	m := meshOf()
-	m.Manifests["bus"] = catalogue.Manifest{Module: "bus", Version: "1", Claims: []catalogue.Claim{{Name: "mesh-broker", Scope: "mesh"}}}
-	m.Manifests["db"] = catalogue.Manifest{Module: "db", Version: "1", Provides: []catalogue.Offer{{Name: "cache"}}}
-	m.Assigned["novox"] = []string{"bus"}
-	m.Assigned["shanks"] = []string{"db"}
-	c := Change{Group: "g", Heads: "0123456789ab", Manifests: map[string]catalogue.Manifest{
-		"web": {Module: "web", Version: "2", Reads: []string{"mesh-controller.assignments"}, Requires: []string{"cache"}}}}
-	v := Compose(m, c, "sdk", 0)
-	if !hasWarning(v, "could run a moved or added module and are not assigned it: ace, novox") || !slices.Contains(v.Machines, "shanks") {
-		t.Errorf("the machines that could run web are not named: %v", v.Warnings)
-	}
-	if !hasWarning(v, "whose grants alone the change alters: novox") {
-		t.Errorf("the machines whose grants alone change are not named: %v", v.Warnings)
-	}
-	c.Manifests["web"] = catalogue.Manifest{Module: "web", Version: "3"}
-	if v := Compose(meshOf(), c, "sdk", 0); hasWarning(v, "grants alone") {
-		t.Errorf("a change altering no grant names machines whose grants change: %v", v.Warnings)
-	}
-}

modules/mesh-delivery-assigner/internal/assign/composer.go

@@ -1,263 +0,0 @@
-package assign
-
-import (
-	"encoding/json"
-	"fmt"
-	"slices"
-	"sort"
-	"strings"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/composer"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-// The cases of a group's composition at its mesh-sdk head: the trunk as it is, and the trunk with the change.
-const (
-	CaseTrunk  = "trunk"
-	CaseChange = "change"
-)
-
-// SDKDir is the directory of mesh-sdk's Go module in its repository, where the composer is built at a head; a reader's
-// composer is built at its repository's root, at the mesh-sdk its go.mod pins.
-const SDKDir = "go"
-
-// The modules whose mesh-sdk reads the manifests a plan sends (ADR 0482 clause 5): the node-engine composes and applies
-// them, the controller being gone (novox/hq ADR 0590, issue 1126). Each is judged at its repository.
-var ReaderModules = map[string]string{"mesh-host": "novox/mesh-host"}
-
-// HeadJob is the compose job of a group with a mesh-sdk member (ADR 0482 clauses 3 and 4, issue 1622): the composer
-// built at the member's head composes the machines the change touches, as the trunk holds them and as the change leaves
-// them, every manifest named by its digest in the indexer's bucket, the seats held from the claims (the assigner's input).
-func HeadJob(m Mesh, c Change) (delivery.ComposeJob, error) {
-	trunk, change := map[string]composer.Manifest{}, map[string]composer.Manifest{}
-	for name, digest := range m.Digests {
-		trunk[name] = composer.Manifest{Digest: digest}
-		change[name] = composer.Manifest{Digest: digest}
-	}
-	for name, digest := range c.Digests {
-		change[name] = composer.Manifest{Digest: digest}
-	}
-	for _, name := range c.Removed {
-		delete(change, name)
-	}
-	in, fromClaims := plainInput(m.Assigned), true
-	if m.Input != nil {
-		// The input the nodes compose from, without its catalogue: the cases carry the manifests (issue 1126).
-		in = *m.Input
-		in.Catalogue = nil
-		fromClaims = len(in.Holdings) == 0
-	}
-	// Each trunk manifest the indexer refused goes in with its verdict, so the composer holds and names it (ADR 0578 §5);
-	// a manifest the change brings has no verdict of the indexer yet, and the checker's judge judges it (§2).
-	changeVerdicts := map[string]delivery.ManifestVerdict{}
-	for name, v := range m.Verdicts {
-		if _, changed := c.Digests[name]; !changed {
-			changeVerdicts[name] = v
-		}
-	}
-	changeCase := composer.Case{Name: CaseChange, Manifests: change, Verdicts: changeVerdicts}
-	req := composer.Request{V: composer.Version, Input: in, Depth: composer.DepthResolve,
-		HoldingsFromClaims: fromClaims, Machines: Touched(m, c),
-		Cases: []composer.Case{{Name: CaseTrunk, Manifests: trunk, Verdicts: m.Verdicts}, changeCase}}
-	return job(SDKRepository, c.SDKHead, SDKDir, req, "the mesh-sdk head of "+c.Group)
-}
-
-// ReaderJob is the compose job that reads the manifests a group changes with the mesh-sdk a reader module pins at
-// commit (ADR 0482 clause 5, issue 1623): no machine is composed, every changed manifest is only read.
-func ReaderJob(c Change, module, repository, commit string) (delivery.ComposeJob, error) {
-	changed := map[string]composer.Manifest{}
-	for name, digest := range c.Digests {
-		changed[name] = composer.Manifest{Digest: digest}
-	}
-	req := composer.Request{V: composer.Version, Cases: []composer.Case{{Name: CaseChange, Manifests: changed}}}
-	return job(repository, commit, delivery.RootPath, req, module+" at "+commit)
-}
-
-func job(repository, commit, dir string, req composer.Request, reader string) (delivery.ComposeJob, error) {
-	raw, err := json.Marshal(req)
-	if err != nil {
-		return delivery.ComposeJob{}, err
-	}
-	return delivery.ComposeJob{Fetch: map[string]any{"repository": repository, "commit": commit}, Dir: dir,
-		Package: composer.Package, Request: raw, Reader: reader}, nil
-}
-
-// plainInput is the composition's input without its catalogue: the nodes by name with what is assigned to them (the
-// composer derives the seats held from the claims, as input does).
-func plainInput(assigned map[string][]string) compose.Input {
-	var in compose.Input
-	nodes := make([]string, 0, len(assigned))
-	for n := range assigned {
-		nodes = append(nodes, n)
-	}
-	sort.Strings(nodes)
-	for _, n := range nodes {
-		in.Nodes = append(in.Nodes, compose.Node{Name: n, Assigned: slices.Clone(assigned[n])})
-	}
-	return in
-}
-
-// Ran is one compose ask's end: its step's state and reason, and the composer's verdict when the step passed.
-type Ran struct {
-	State   string
-	Reason  string
-	Verdict *composer.Verdict
-}
-
-// RanOf reads a compose ask's end from its step value; a step that passed with an answer that cannot be read is a
-// failure, named.
-func RanOf(step delivery.Step) Ran {
-	r := Ran{State: step.State, Reason: step.Reason}
-	if step.State != delivery.StepPassed {
-		return r
-	}
-	var a delivery.ComposeAnswer
-	var v composer.Verdict
-	if err := json.Unmarshal(step.Result, &a); err != nil {
-		return Ran{State: delivery.StepFailed, Reason: "the compose step's answer cannot be read: " + err.Error()}
-	}
-	if err := json.Unmarshal(a.Verdict, &v); err != nil || v.V != composer.Version {
-		return Ran{State: delivery.StepFailed, Reason: fmt.Sprintf("the composer's verdict cannot be read (version %d): %v", v.V, err)}
-	}
-	r.Verdict = &v
-	return r
-}
-
-func caseOf(v *composer.Verdict, name string) (composer.CaseVerdict, bool) {
-	if v == nil {
-		return composer.CaseVerdict{}, false
-	}
-	for _, c := range v.Cases {
-		if c.Name == name {
-			return c, true
-		}
-	}
-	return composer.CaseVerdict{}, false
-}
-
-// Reader is one module whose mesh-sdk reads the group's manifests, at the commit judged: the group's member head when
-// the group holds one in its repository, else a build its node runs.
-type Reader struct {
-	Module, Commit string
-	Member         bool
-	Ran            Ran
-}
-
-// FromComposer is the composition check of a group with a mesh-sdk member, judged from the composer built at its head
-// (ADR 0482 clauses 3 to 5, issues 1622 and 1623): the same failures as Compose, read from the composer's two cases, the
-// verdict naming the mesh-sdk the composer was built with; a trunk manifest the head's mesh-sdk cannot decode fails too
-// (the group would deliver a reader that cannot read it). A reader that cannot read a changed manifest is a warning,
-// never a failure: it decodes leniently and sets a field it does not know aside (novox/hq ADR 0578 §6, which changes
-// ADR 0482 §5).
-func FromComposer(m Mesh, c Change, head Ran, readers []Reader, took time.Duration) delivery.CompositionVerdict {
-	v := delivery.CompositionVerdict{Group: c.Group, Heads: c.Heads, SDK: "mesh-sdk " + c.SDKHead, Took: took.Milliseconds()}
-	machines := Touched(m, c)
-	v.Machines = machines
-	var fails []string
-	if head.State != delivery.StepPassed {
-		v.Words = fmt.Sprintf("the composer at mesh-sdk %s did not run: %s %s", c.SDKHead, head.State, head.Reason)
-		v.State = delivery.CompositionFail
-		return v
-	}
-	if head.Verdict.SDK != "" {
-		v.SDK = head.Verdict.SDK
-	}
-	trunk, okT := caseOf(head.Verdict, CaseTrunk)
-	change, okC := caseOf(head.Verdict, CaseChange)
-	if !okT || !okC {
-		v.State, v.Words = delivery.CompositionFail, "the composer's verdict holds no trunk or no change case"
-		return v
-	}
-	failAt := func(machine, words string) {
-		if v.Machine == "" && machine != "" {
-			v.Machine = machine
-		}
-		fails = append(fails, words)
-	}
-	for _, name := range sortedKeys(c.Digests) {
-		if r := change.Manifests[name]; !r.Accepted {
-			failAt("", fmt.Sprintf("the manifest of %s cannot be read by mesh-sdk %s: %s", name, c.SDKHead, r.Refused))
-		}
-	}
-	for _, name := range sortedKeys(trunk.Manifests) {
-		if _, changed := c.Digests[name]; changed || slices.Contains(c.Removed, name) || trunk.Manifests[name].Accepted {
-			continue
-		}
-		if _, before := m.Unreadable[name]; before {
-			continue // already unreadable on the trunk: not the group's doing
-		}
-		failAt("", fmt.Sprintf("mesh-sdk %s refuses the trunk's manifest of %s, which the group does not change: %s", c.SDKHead, name, trunk.Manifests[name].Refused))
-	}
-	for _, name := range sortedKeys(c.Twice) {
-		failAt("", fmt.Sprintf("%s is defined twice, in %s", name, strings.Join(c.Twice[name], " and ")))
-	}
-	for _, node := range machines {
-		for _, name := range c.Removed {
-			if slices.Contains(m.Assigned[node], name) {
-				failAt(node, fmt.Sprintf("%s runs %s, which the change removes from its source", node, name))
-			}
-		}
-		before, now := trunk.Machines[node], change.Machines[node]
-		switch {
-		case now.Composes:
-		case !before.Composes:
-			v.Warnings = append(v.Warnings, fmt.Sprintf("%s does not compose on the trunk either, so the change is not blamed: %s", node, before.Reason))
-		default:
-			failAt(node, fmt.Sprintf("%s composes on the trunk and not with the change: %s", node, now.Reason))
-		}
-	}
-	readerFails, readerWarnings := judgeReaders(c, change, readers)
-	fails = append(fails, readerFails...)
-	v.Warnings = append(v.Warnings, readerWarnings...)
-	if m.InputUnread != "" {
-		v.Warnings = append(v.Warnings, "composed over the nodes and their assignments alone: the input the nodes compose from "+
-			"cannot be read from the bus ("+m.InputUnread+")")
-	}
-	return finish(v, m, c, machines, fails)
-}
-
-// NoComposer says whether a compose step failed because the mesh-sdk it was built at has no composer command (a mesh-sdk
-// from before issue 1621): Go's words for a package its module does not hold.
-func NoComposer(reason string) bool {
-	for _, words := range []string{"cannot find package", "no required module provides package", "is not in std", "cannot find module providing package", "does not contain package"} {
-		if strings.Contains(reason, words) {
-			return true
-		}
-	}
-	return false
-}
-
-func judgeReaders(c Change, head composer.CaseVerdict, readers []Reader) (fails, warnings []string) {
-	for _, r := range readers {
-		at := r.Module + " at " + r.Commit
-		if r.Member {
-			at = r.Module + "'s member head " + r.Commit
-		}
-		if r.Ran.State != delivery.StepPassed {
-			if NoComposer(r.Ran.Reason) {
-				warnings = append(warnings, fmt.Sprintf("not judged whether %s reads the group's manifests: the mesh-sdk it pins has no "+
-					"composer command (before issue 1621)", at))
-				continue
-			}
-			fails = append(fails, fmt.Sprintf("the composer of the mesh-sdk %s pins did not run: %s %s", at, r.Ran.State, r.Ran.Reason))
-			continue
-		}
-		read, ok := caseOf(r.Ran.Verdict, CaseChange)
-		if !ok {
-			fails = append(fails, fmt.Sprintf("the composer of the mesh-sdk %s pins answered no change case", at))
-			continue
-		}
-		for _, name := range sortedKeys(c.Digests) {
-			if !head.Manifests[name].Accepted || read.Manifests[name].Accepted {
-				continue
-			}
-			// ADR 0578 §6: no longer a failure; the reader sets what it does not know aside, and the part that needs it takes
-			// the newer package (ADR 0573 §2).
-			warnings = append(warnings, fmt.Sprintf("the manifest of %s uses what %s (mesh-sdk %s) cannot read: %s; it reads the rest "+
-				"once it takes mesh-sdk %s", name, at, r.Ran.Verdict.SDK, read.Manifests[name].Refused, c.SDKHead))
-		}
-	}
-	return fails, warnings
-}

modules/mesh-delivery-assigner/internal/assign/composer_test.go

@@ -1,225 +0,0 @@
-package assign
-
-import (
-	"encoding/json"
-	"slices"
-	"strings"
-	"testing"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/catalogue"
-	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/composer"
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-var testTime = time.Date(2026, 10, 24, 3, 0, 0, 0, time.UTC)
-
-const sdkHead = "1111111111111111111111111111111111111111"
-
-// raws are the manifests of meshOf as their repositories hold them, by digest, as the indexer keeps them; `web2` is web
-// with a field `shares` that the assigner's own mesh-sdk does not read (the shape of issue 1593).
-var raws = map[string]string{
-	"d-mail":  `{"module": "mail", "version": "1", "requires": ["postgres-database"]}`,
-	"d-store": `{"module": "store", "version": "1", "provides": [{"name": "postgres-database"}]}`,
-	"d-web":   `{"module": "web", "version": "1"}`,
-	"d-web2":  `{"module": "web", "version": "2", "shares": ["photos"]}`,
-}
-
-// asTheHeadReads is how mesh-sdk at the group's head reads each manifest: as the assigner's own reads it, but for the
-// field it adds, which it accepts. The head's composer is built and run by the Go build module (ADR 0482 clause 4); here
-// its verdict is made by mesh-sdk's composer.Run over the same request, with `web2` read as the head reads it.
-var asTheHeadReads = map[string]string{"d-web2": `{"module": "web", "version": "2"}`}
-
-func digestedMesh() Mesh {
-	m := meshOf()
-	m.Digests = map[string]string{"mail": "d-mail", "store": "d-store", "web": "d-web"}
-	return m
-}
-
-// webShares is a group of mesh-sdk and mesh-catalog whose catalogue member gives web the field only the SDK head reads:
-// the assigner's own reader refuses it (Unreadable), as the indexer's manifest is read in world.change.
-func webShares(members map[string]string) Change {
-	// As an older reader refused it; the field set aside by the lenient decoder is named the same (ADR 0578 §6).
-	m, _ := catalogue.Decode([]byte(raws["d-web2"]))
-	return Change{Group: "g", Heads: "0123456789ab", SDKHead: sdkHead, Manifests: map[string]catalogue.Manifest{},
-		Unreadable: map[string]string{"web": m.SetAside()}, Digests: map[string]string{"web": "d-web2"}, Members: members}
-}
-
-// run is the composer's step for a job, as the build module answers it: the request filled from the indexer's digests
-// (with read standing in for how that mesh-sdk reads a digest), run, and its verdict put in a passed step.
-func run(t *testing.T, job delivery.ComposeJob, read map[string]string) Ran {
-	t.Helper()
-	req, err := composer.Decode(job.Request)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := composer.Fill(&req, func(d string) ([]byte, error) {
-		if r, ok := read[d]; ok {
-			return []byte(r), nil
-		}
-		return []byte(raws[d]), nil
-	}); err != nil {
-		t.Fatal(err)
-	}
-	v, err := composer.Run(req)
-	if err != nil {
-		t.Fatal(err)
-	}
-	v.SDK = "(devel) " + job.Fetch["commit"].(string)
-	vr, _ := json.Marshal(v)
-	ans, _ := json.Marshal(delivery.ComposeAnswer{Built: true, Key: "composer-0", Verdict: vr})
-	return RanOf(delivery.Step{State: delivery.StepPassed, Result: ans})
-}
-
-// 1622/AC1: a group holding a mesh-sdk pull request is composed by the composer built at the member's head: the job
-// fetches mesh-sdk at that head, builds mesh-sdk's composer command in its Go module, and hands it the trunk and the
-// change by digest, never the manifests' bytes, composing the machines the change touches.
-func TestAGroupWithAnSDKMemberAsksTheComposerAtItsHead(t *testing.T) {
-	c := webShares(nil)
-	job, err := HeadJob(digestedMesh(), c)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if job.Fetch["repository"] != SDKRepository || job.Fetch["commit"] != sdkHead || job.Dir != "go" || job.Package != composer.Package {
-		t.Fatalf("job = %+v", job)
-	}
-	ask := delivery.StepAsk{ID: "mh3k2x9qa1b2c5", Kind: delivery.AskCheck, Language: delivery.AskGo, Asker: "mesh-delivery-assigner",
-		At: testTime, Compose: &job}
-	if _, err := delivery.EncodeStepAsk(ask); err != nil {
-		t.Fatalf("the ask is refused by its layout: %v", err)
-	}
-	req, err := composer.Decode(job.Request)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(req.Cases) != 2 || req.Cases[0].Name != CaseTrunk || req.Cases[1].Name != CaseChange {
-		t.Fatalf("cases = %+v", req.Cases)
-	}
-	if req.Cases[0].Manifests["web"].Digest != "d-web" || req.Cases[1].Manifests["web"].Digest != "d-web2" || len(req.Cases[1].Manifests["web"].Raw) != 0 {
-		t.Errorf("the cases do not name web by its trunk and its change digest: %+v", req.Cases)
-	}
-	if !slices.Equal(req.Machines, []string{"g14"}) || req.Depth != composer.DepthResolve || !req.HoldingsFromClaims {
-		t.Errorf("request = machines %v, depth %q, holdings from claims %v", req.Machines, req.Depth, req.HoldingsFromClaims)
-	}
-
-	// 1126 (ADR 0547 §2, ADR 0549 §3): once the catalogue places the nodes, the check composes over the input the nodes
-	// compose from (frombus), its catalogue left to the cases, and the seats held as placement says.
-	m := digestedMesh()
-	m.Input = &compose.Input{Catalogue: map[string]catalogue.Manifest{"web": {Module: "web"}},
-		Nodes:    []compose.Node{{Name: "g14", Assigned: []string{"web"}, Place: compose.Place{Endpoint: "g14.example:51820"}}},
-		Holdings: []catalogue.Held{{Claim: "web-seat", Scope: "mesh", Node: "g14", Module: "web"}}}
-	placedJob, err := HeadJob(m, c)
-	if err != nil {
-		t.Fatal(err)
-	}
-	placed, err := composer.Decode(placedJob.Request)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if placed.Input.Catalogue != nil || len(placed.Input.Nodes) != 1 || placed.Input.Nodes[0].Place.Endpoint != "g14.example:51820" ||
-		len(placed.Input.Holdings) != 1 || placed.HoldingsFromClaims {
-		t.Errorf("the placed check's request = %+v, holdings from claims %v", placed.Input, placed.HoldingsFromClaims)
-	}
-}
-
-// 1622/AC2, AC3: a catalogue member using a field only the SDK head reads passes with the head's composer, and the
-// verdict names the mesh-sdk the composer was built with; with the assigner's own mesh-sdk it fails.
-func TestAFieldTheGroupAddsPassesWithTheHeadsComposer(t *testing.T) {
-	c := webShares(map[string]string{"novox/mesh-controller": "2222222222222222222222222222222222222222"})
-	job, _ := HeadJob(digestedMesh(), c)
-	head := run(t, job, asTheHeadReads)
-	v := FromComposer(digestedMesh(), c, head, nil, 0)
-	if v.State != delivery.CompositionPass || v.SDK != "(devel) "+sdkHead || !slices.Equal(v.Machines, []string{"g14"}) {
-		t.Fatalf("with the head's composer: %+v", v)
-	}
-	if _, err := delivery.EncodeCompositionVerdict(v); err != nil {
-		t.Errorf("the verdict cannot be written: %v", err)
-	}
-	own := Compose(digestedMesh(), c, "v0.1.14-own", 0)
-	if own.State != delivery.CompositionFail || !strings.Contains(own.Words, "shares") {
-		t.Fatalf("with the assigner's own mesh-sdk: %+v, want a fail naming the field", own)
-	}
-}
-
-// 1623/AC1, AC2 as ADR 0578 §6 changes them: the group of mesh-sdk and mesh-catalog adding and using a field, without a
-// controller member, passes with a warning naming the field and mesh-controller, whose running build pins an older
-// mesh-sdk that cannot read it: a reader sets a field it does not know aside, so it fails nothing. With a controller
-// member pinned to the SDK head it passes with no such warning.
-func TestAFieldTheRunningControllerCannotReadIsAWarning(t *testing.T) {
-	c := webShares(nil)
-	job, _ := HeadJob(digestedMesh(), c)
-	head := run(t, job, asTheHeadReads)
-	running := "3333333333333333333333333333333333333333"
-	rjob, err := ReaderJob(c, "mesh-controller", "novox/mesh-controller", running)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if rjob.Fetch["commit"] != running || rjob.Dir != delivery.RootPath {
-		t.Fatalf("reader job = %+v", rjob)
-	}
-	// The running controller's mesh-sdk, older than the lenient decoder, refuses web2 for its field.
-	old := Ran{State: delivery.StepPassed, Verdict: &composer.Verdict{V: composer.Version, SDK: "v0.1.13", Cases: []composer.CaseVerdict{
-		{Name: CaseChange, Manifests: map[string]composer.ManifestRead{"web": {Refused: `json: unknown field "shares"`}}}}}}
-	v := FromComposer(digestedMesh(), c, head, []Reader{{Module: "mesh-controller", Commit: running, Ran: old}}, 0)
-	if v.State != delivery.CompositionPass || !hasWarning(v, "shares") || !hasWarning(v, "mesh-controller at "+running) {
-		t.Fatalf("without a controller member: %+v, want a pass warning of the field and mesh-controller", v)
-	}
-	member := "2222222222222222222222222222222222222222"
-	pinned := run(t, rjob, asTheHeadReads)
-	v = FromComposer(digestedMesh(), c, head, []Reader{{Module: "mesh-controller", Commit: member, Member: true, Ran: pinned}}, 0)
-	if v.State != delivery.CompositionPass {
-		t.Fatalf("with a controller member pinned to the head: %+v, want a pass", v)
-	}
-}
-
-// 1623: a reader whose mesh-sdk has no composer command (before issue 1621) is said, not failed; a reader's composer that
-// failed for another cause fails the group, loud.
-func TestAReaderWithNoComposerIsSaidAndAnotherFailureFails(t *testing.T) {
-	c := webShares(nil)
-	job, _ := HeadJob(digestedMesh(), c)
-	head := run(t, job, asTheHeadReads)
-	none := Ran{State: delivery.StepFailed, Reason: "go build: no required module provides package git.novox.be/novox/mesh-sdk/go/cmd/mesh-compose"}
-	v := FromComposer(digestedMesh(), c, head, []Reader{{Module: "mesh-host", Commit: "abc", Ran: none}}, 0)
-	if v.State != delivery.CompositionPass || !hasWarning(v, "mesh-host at abc") || !hasWarning(v, "before issue 1621") {
-		t.Fatalf("a reader with no composer: %+v", v)
-	}
-	broke := Ran{State: delivery.StepFailed, Reason: "the fetch could not reach the forge"}
-	v = FromComposer(digestedMesh(), c, head, []Reader{{Module: "mesh-host", Commit: "abc", Ran: broke}}, 0)
-	if v.State != delivery.CompositionFail || !strings.Contains(v.Words, "could not reach the forge") {
-		t.Fatalf("a reader whose composer failed: %+v", v)
-	}
-}
-
-// 1622: the head's composer that did not run fails the composition naming why, never passes it; a trunk manifest the
-// head's mesh-sdk refuses fails it too, since the group would deliver a reader that refuses it.
-func TestTheHeadsComposerFailingOrRefusingTheTrunkFails(t *testing.T) {
-	c := webShares(nil)
-	v := FromComposer(digestedMesh(), c, Ran{State: delivery.StepRefused, Reason: "the guard refuses it"}, nil, 0)
-	if v.State != delivery.CompositionFail || !strings.Contains(v.Words, "the guard refuses it") || !strings.Contains(v.Words, sdkHead) {
-		t.Fatalf("a head composer that did not run: %+v", v)
-	}
-	job, _ := HeadJob(digestedMesh(), c)
-	strict := map[string]string{"d-web2": asTheHeadReads["d-web2"], "d-mail": `{"module": "mail", "version": "1", "requires": "x"}`}
-	v = FromComposer(digestedMesh(), c, run(t, job, strict), nil, 0)
-	if v.State != delivery.CompositionFail || !strings.Contains(v.Words, "refuses the trunk's manifest of mail") {
-		t.Fatalf("a head that refuses a trunk manifest: %+v", v)
-	}
-	// ADR 0578 §5: a trunk manifest the indexer refused goes into the composer's input with its verdict, in both cases;
-	// the composer holds and names it, and the group is not blamed for it.
-	m := digestedMesh()
-	m.Verdicts = map[string]delivery.ManifestVerdict{"mail": {Module: "mail", State: delivery.VerdictRefused, Problems: []string{"it is wrong"}}}
-	m.Unreadable = map[string]string{"mail": m.Verdicts["mail"].Why()}
-	job, _ = HeadJob(m, c)
-	var req composer.Request
-	if err := json.Unmarshal(job.Request, &req); err != nil || !req.Cases[0].Verdicts["mail"].Refused() || !req.Cases[1].Verdicts["mail"].Refused() {
-		t.Fatalf("the request carries no verdict: %+v %v", req.Cases, err)
-	}
-	head := run(t, job, asTheHeadReads)
-	if trunk, _ := caseOf(head.Verdict, CaseTrunk); !strings.Contains(trunk.Manifests["mail"].Refused, "refused the manifest of mail: it is wrong") {
-		t.Fatalf("the composer did not name the refusal: %+v", trunk.Manifests["mail"])
-	}
-	if v = FromComposer(m, c, head, nil, 0); v.State != delivery.CompositionPass {
-		t.Fatalf("a refusal on the trunk blamed the group: %+v", v)
-	}
-}

modules/mesh-delivery-assigner/internal/judge/judge.go

@@ -0,0 +1,331 @@
+// Package judge is how the seat mesh-placement's holder judges a proposal (novox/hq ADR 0567 §3, §4, as ADR 0593 §8
+// changes them): what it changes on each node by its placement (Intended), every node answering it, and the verdict of
+// their answers (JudgeAnswers). The assigner's own (ADR 0593 §1), moved back from mesh-sdk's compose/judge: the holder
+// composes nothing, since every composition is its node's engine's, and a node answers through the candidates path
+// with what it composed. It holds no bus client and no timer: the holder gives it what it read.
+package judge
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// AnswerBound is how long the holder waits for a node's answer after its candidate was written: the time to live of the
+// node's pulse key (delivery.PulseAnswerKey), whose expiry names it as giving no answer, never passed. The same answer
+// bound a check gives a node (ADR 0593 §8, §7: 60 seconds, delivery.ComposeAnswerBound). A variable so a test on the bus
+// can shorten it.
+var AnswerBound = delivery.ComposeAnswerBound
+
+// Intended is, by node, the modules whose placed entry the proposal changes there, and the nodes that answer it: every
+// node (ADR 0593 §8, changing ADR 0567 §4's list of the nodes that must answer), sorted. current is the placement as it
+// stands, laid the proposal's placements by node (nil removes the node's key) and nodes every node with a record. A
+// node's set holds the modules the proposal adds, removes or whose placed entry differs on that node; a node with no
+// key now gets an empty set (§7: the seed is answered as the same). What a node's compositions change beyond its own
+// placement it says itself in its answer, marked in the brief as not computed.
+func Intended(current map[string]delivery.Placement, laid map[string]*delivery.Placement, nodes []string) (intended map[string]map[string]bool, must []string) {
+	intended = map[string]map[string]bool{}
+	all := map[string]bool{}
+	for _, n := range nodes {
+		all[n] = true
+	}
+	for n := range laid {
+		all[n] = true
+	}
+	for node := range all {
+		must = append(must, node)
+		set := map[string]bool{}
+		intended[node] = set
+		before, placed := current[node]
+		after, changesKey := laid[node]
+		if !changesKey || !placed {
+			continue // untouched, or new to placement: every answer must be the same
+		}
+		var afterModules []delivery.PlacedModule
+		if after != nil {
+			afterModules = after.Modules
+		}
+		entries := map[string]delivery.PlacedModule{}
+		for _, m := range before.Modules {
+			entries[m.Module] = m
+		}
+		seen := map[string]bool{}
+		for _, m := range afterModules {
+			seen[m.Module] = true
+			if e, ok := entries[m.Module]; !ok || !reflect.DeepEqual(e, m) {
+				set[m.Module] = true
+			}
+		}
+		for name := range entries {
+			if !seen[name] {
+				set[name] = true
+			}
+		}
+	}
+	sort.Strings(must)
+	return intended, must
+}
+
+// JudgeAnswers is the verdict of a proposal's answers (§4). answers is by node its HaveNode.Candidates entry for the
+// proposal (nil when it has none) and revisions by node the revision of its candidate key: an answer counts when it
+// names the proposal and that revision. It fails on a refusal by a node that must answer; a node of Must with no answer
+// that counts is waited for while its pulse key stands, and once it has ended (pulsing false: the bound's expiry, heard
+// on the bus) is named as giving no answer and the proposal decided on the answers it has (ADR 0593 §8).
+// A difference fails nothing: one Intended computed is listed under Intended, one it did not under Unintended, both
+// shown in the ask's brief. The seed alone fails on any difference.
+func JudgeAnswers(p delivery.PlacementProposal, intended map[string]map[string]bool, answers map[string]*delivery.CandidateAnswer,
+	revisions map[string]uint64, online map[string]bool, pulsing map[string]bool, now time.Time) delivery.PlacementVerdict {
+	v := delivery.PlacementVerdict{At: now.UTC(), Intended: map[string][]string{}, Unintended: map[string][]string{}, Carried: map[string][]string{},
+		Answers: map[string]delivery.CandidateAnswer{}}
+	for node, set := range intended {
+		for m := range set {
+			v.Intended[node] = append(v.Intended[node], m)
+		}
+		sort.Strings(v.Intended[node])
+	}
+	must := p.Must
+	if len(must) == 0 {
+		must = p.Nodes()
+	}
+	for _, node := range must {
+		a := answers[node]
+		if a == nil || a.Proposal != p.ID || a.Revision == 0 || a.Revision != revisions[node] {
+			v.Silent = append(v.Silent, node)
+			continue
+		}
+		v.Answers[node] = *a
+		if a.Refused != "" {
+			v.Fails = append(v.Fails, fmt.Sprintf("%s cannot compose the proposal: %s", node, a.Refused))
+			continue
+		}
+		for _, r := range a.Refusals {
+			v.Fails = append(v.Fails, fmt.Sprintf("%s refuses the proposal for %s: %s", node, r.Module, r.Why))
+		}
+		want := intended[node]
+		differs := func(module, words string) {
+			if p.Seed {
+				// The seed carries what its nodes found, each named in the brief for the operator who approves it.
+				v.Carried[node] = append(v.Carried[node], words)
+				return
+			}
+			if !want[module] {
+				v.Unintended[node] = append(v.Unintended[node], module)
+			}
+		}
+		for _, d := range a.Differs {
+			differs(d.Module, differenceWords(d))
+		}
+		for _, d := range a.Added {
+			differs(d.Module, "would run "+d.Module)
+		}
+		for _, m := range a.Removed {
+			differs(m, "would stop running "+m)
+		}
+		sort.Strings(v.Unintended[node])
+	}
+	if len(v.Intended) == 0 {
+		v.Intended = nil
+	}
+	if len(v.Unintended) == 0 {
+		v.Unintended = nil
+	}
+	if len(v.Carried) == 0 {
+		v.Carried = nil
+	}
+	if len(v.Answers) == 0 {
+		v.Answers = nil
+	}
+	var waiting, gone []string
+	for _, node := range v.Silent {
+		named := node
+		if online != nil && !online[node] {
+			named += " (offline)"
+		}
+		if pulsing[node] {
+			waiting = append(waiting, named)
+		} else {
+			gone = append(gone, named)
+		}
+	}
+	if len(waiting) > 0 {
+		v.Notes = append(v.Notes, fmt.Sprintf("waits for the answers of %s, each for %s from its candidate's write",
+			strings.Join(waiting, ", "), AnswerBound))
+	}
+	if len(gone) > 0 {
+		// ADR 0593 §8: decided on the answers it has; that node's own composition judges again when it applies (§9).
+		v.Notes = append(v.Notes, fmt.Sprintf("no answer from %s within %s of its candidate's write: decided on the answers "+
+			"it has, and that node's own composition judges again when it applies", strings.Join(gone, ", "), AnswerBound))
+	}
+	switch {
+	case len(v.Fails) > 0:
+		v.State = delivery.VerdictFail
+	case len(waiting) > 0:
+		v.State = delivery.VerdictWaits
+	default:
+		v.State = delivery.VerdictPass
+	}
+	return v
+}
+
+// Brief is the verdict as the ask's brief shows it, by node (§5): what the proposal changes and what each node answered
+// beside it, marked, and what stays held as the node holds it today, with the proposal's why.
+func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
+	var b strings.Builder
+	fmt.Fprintf(&b, "%s (proposed by %s)", p.Why, p.By)
+	nodes := map[string]bool{}
+	for n := range v.Intended {
+		nodes[n] = true
+	}
+	for n := range v.Unintended {
+		nodes[n] = true
+	}
+	for _, n := range p.Nodes() {
+		nodes[n] = true
+	}
+	for n, a := range v.Answers {
+		if len(a.Held) > 0 {
+			nodes[n] = true
+		}
+	}
+	for n := range v.Carried {
+		nodes[n] = true
+	}
+	names := make([]string, 0, len(nodes))
+	for n := range nodes {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	for _, n := range names {
+		fmt.Fprintf(&b, "; %s:", n)
+		if m := v.Intended[n]; len(m) > 0 {
+			fmt.Fprintf(&b, " changes %s", strings.Join(m, ", "))
+		} else {
+			b.WriteString(" composes the same")
+		}
+		if m := v.Unintended[n]; len(m) > 0 {
+			fmt.Fprintf(&b, "; also differs, not computed: %s", strings.Join(m, ", "))
+		}
+		if m := v.Carried[n]; len(m) > 0 {
+			fmt.Fprintf(&b, "; the seed carries: %s", strings.Join(m, "; "))
+		}
+		if held := v.Answers[n].Held; len(held) > 0 {
+			var names []string
+			for _, h := range held {
+				today := h.Today
+				if today == "" {
+					today = "held"
+				}
+				names = append(names, h.Module+" ("+today+")")
+			}
+			fmt.Fprintf(&b, "; stays as today: %s", strings.Join(names, ", "))
+		}
+	}
+	return b.String()
+}
+
+// differenceWords names one module's difference: the module, the first field that differs in it with its value as it
+// runs and as the seed composes it, each cut to about 60 characters ("(value cut)" where a body shown is cut before the
+// field), and how many fields more; or the resource and why when no body is shown.
+func differenceWords(d delivery.ModuleDiffers) string {
+	for _, b := range d.Bodies {
+		if len(b.Paths) == 0 {
+			continue
+		}
+		path := b.Paths[0]
+		words := fmt.Sprintf("%s: %s %s → %s", d.Module, fieldName(b.Running, b.Composed, path),
+			valueAt(b.Running, path), valueAt(b.Composed, path))
+		if n := len(b.Paths) - 1; n > 0 {
+			words += fmt.Sprintf(" (and %d more fields)", n)
+		}
+		return words
+	}
+	if d.Resource != "" {
+		return fmt.Sprintf("%s: %s (%s)", d.Module, d.Resource, d.Why)
+	}
+	return fmt.Sprintf("%s: %s", d.Module, d.Why)
+}
+
+// shownValue bounds a value named in a brief.
+const shownValue = 60
+
+// walk follows a differing path (delivery.DifferingPaths: keys joined by dots, a key may hold dots, and a JSON value
+// written in a string is read as JSON) through a body, answering the keys it passed and the value at its end.
+func walk(body, path string) (keys []string, value any, ok bool) {
+	var v any
+	if json.Unmarshal([]byte(body), &v) != nil {
+		return nil, nil, false
+	}
+	rest := path
+	for rest != "" {
+		if s, isString := v.(string); isString {
+			var inner any
+			if json.Unmarshal([]byte(s), &inner) != nil {
+				return nil, nil, false
+			}
+			v = inner
+		}
+		switch t := v.(type) {
+		case map[string]any:
+			best := ""
+			for k := range t {
+				if (rest == k || strings.HasPrefix(rest, k+".")) && len(k) > len(best) {
+					best = k
+				}
+			}
+			if best == "" {
+				return nil, nil, false
+			}
+			keys, v, rest = append(keys, best), t[best], strings.TrimPrefix(strings.TrimPrefix(rest, best), ".")
+		case []any:
+			seg, after, _ := strings.Cut(rest, ".")
+			n, err := strconv.Atoi(seg)
+			if err != nil || n < 0 || n >= len(t) {
+				return nil, nil, false
+			}
+			keys, v, rest = append(keys, seg), t[n], after
+		default:
+			return nil, nil, false
+		}
+	}
+	return keys, v, true
+}
+
+// valueAt is the value at path in a shown body, cut to shownValue, or why it is not shown.
+func valueAt(body, path string) string {
+	if body == "" {
+		return "(none)"
+	}
+	_, v, ok := walk(body, path)
+	if !ok {
+		return "(value cut)"
+	}
+	s, isString := v.(string)
+	if !isString {
+		raw, _ := json.Marshal(v)
+		s = string(raw)
+	}
+	if r := []rune(s); len(r) > shownValue {
+		s = string(r[:shownValue-1]) + "…"
+	}
+	return s
+}
+
+// fieldName is the differing field as a person reads it: its parent's name and its own, `PARENT[key]`, from whichever
+// body reaches it; the path's end when neither does.
+func fieldName(running, composed, path string) string {
+	for _, body := range []string{running, composed} {
+		if keys, _, ok := walk(body, path); ok && len(keys) > 0 {
+			if len(keys) == 1 {
+				return keys[0]
+			}
+			return keys[len(keys)-2] + "[" + keys[len(keys)-1] + "]"
+		}
+	}
+	return path
+}

modules/mesh-delivery-assigner/internal/judge/judge_test.go

@@ -0,0 +1,91 @@
+package judge
+
+import (
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// ADR 0567 §3, §4 (rows moved from the assigner's check of a pull request's placement, ADR 0559 §5): what a proposal
+// changes by node, and the verdict of the answers: differences shown and failing nothing, a refusal and a silent node
+// failing, a later answer judging again, the seed failing on any difference.
+func TestJudge(t *testing.T) {
+	current := map[string]delivery.Placement{"anchor": {Node: "anchor", Modules: []delivery.PlacedModule{{Module: "mail"}}}, "server": {Node: "server"}}
+	laid := map[string]*delivery.Placement{
+		"anchor": {Node: "anchor", Modules: []delivery.PlacedModule{{Module: "mail", Ports: map[string]int{"25": 2525}}, {Module: "web"}}},
+		"laptop": {Node: "laptop", Modules: []delivery.PlacedModule{{Module: "web"}}}}
+	// ADR 0593 §8: every node answers; what the placement changes is read from the placement alone.
+	got, must := Intended(current, laid, []string{"anchor", "laptop", "server"})
+	if !got["anchor"]["mail"] || !got["anchor"]["web"] || len(got["laptop"]) != 0 || len(got["server"]) != 0 ||
+		!slices.Equal(must, []string{"anchor", "laptop", "server"}) {
+		t.Errorf("intended = %v, must %v: want anchor's mail and web, nothing elsewhere, every node answering", got, must)
+	}
+
+	at := time.Date(2026, 10, 27, 2, 0, 0, 0, time.UTC)
+	p := delivery.PlacementProposal{ID: "p-one", By: "op", Why: "move web", Written: at, Base: map[string]uint64{"anchor": 3, "laptop": 0},
+		Must: []string{"anchor", "laptop"}}
+	revisions := map[string]uint64{"anchor": 7, "laptop": 8}
+	intended := map[string]map[string]bool{"anchor": {"web": true}}
+	same := func(rev uint64) *delivery.CandidateAnswer {
+		return &delivery.CandidateAnswer{Proposal: "p-one", Revision: rev, Verdict: delivery.CandidateSame, Same: []string{"mail"}}
+	}
+	differs := func(rev uint64, module string) *delivery.CandidateAnswer {
+		return &delivery.CandidateAnswer{Proposal: "p-one", Revision: rev, Verdict: delivery.CandidateDiffers,
+			Differs: []delivery.ModuleDiffers{{Module: module, Why: "the port differs"}}}
+	}
+	for _, row := range []struct {
+		name    string
+		seed    bool
+		answers map[string]*delivery.CandidateAnswer
+		pulsing map[string]bool
+		state   string
+		words   string
+		marked  string
+	}{
+		{"all the same", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": same(8)}, nil, delivery.VerdictPass, "", ""},
+		{"a module added where intended", false, map[string]*delivery.CandidateAnswer{"anchor": {Proposal: "p-one", Revision: 7, Verdict: delivery.CandidateDiffers,
+			Added: []delivery.ModuleAdded{{Module: "web", Unissued: []string{"its own secret"}}}}, "laptop": same(8)}, nil, delivery.VerdictPass, "", ""},
+		{"a difference not computed passes, marked", false, map[string]*delivery.CandidateAnswer{"anchor": differs(7, "mail"), "laptop": same(8)}, nil, delivery.VerdictPass, "", "mail"},
+		{"the seed carries a difference, named", true, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": {Proposal: "p-one", Revision: 8,
+			Verdict: delivery.CandidateDiffers, Differs: []delivery.ModuleDiffers{{Module: "node-tools", Resource: "node-tools.runtime", Why: "the resource differs",
+				Bodies: []delivery.ResourceBodies{{ID: "node-tools.runtime", Paths: []string{"env.MESH_OWNED_PATHS./etc/resolv.conf", "env.MESH_TOOL_MODULES"},
+					Running:  `{"env":{"MESH_OWNED_PATHS":"{\"/etc/hosts\":\"hostname\",\"/etc/resolv.conf\":\"networkmanager (node-uplink)\"}"}}`,
+					Composed: `{"env":{"MESH_OWNED_PATHS":"{\"/etc/hosts\":\"hostname\",\"/etc/resolv.conf\":\"systemd-resolved (node-resolver)\"}","MESH_TOOL_MODULES":"… (cut at 8192 bytes)`}}}}}}, nil, delivery.VerdictPass, "", ""},
+		{"a refusal", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": {Proposal: "p-one", Revision: 8, Verdict: delivery.CandidateRefused,
+			Refusals: []delivery.ModuleRefused{{Module: "web", Why: "no own secret"}}}}, nil, delivery.VerdictFail, "laptop refuses", ""},
+		{"a node not answering, within its bound", false, map[string]*delivery.CandidateAnswer{"anchor": same(7)}, map[string]bool{"laptop": true}, delivery.VerdictWaits, "laptop (offline)", ""},
+		{"an answer of an earlier revision, past its bound, is no answer and decided without it", false, map[string]*delivery.CandidateAnswer{"anchor": same(6), "laptop": same(8)}, nil, delivery.VerdictPass, "no answer from anchor", ""},
+		{"a module held as today passes, shown in the brief", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": {Proposal: "p-one", Revision: 8,
+			Verdict: delivery.CandidateSame, Held: []delivery.ModuleRefused{{Module: "spiegel", Why: "a required value is unset"}}}}, nil, delivery.VerdictPass, "", ""},
+		{"its later answer", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": same(8)}, nil, delivery.VerdictPass, "", ""},
+	} {
+		q := p
+		q.Seed = row.seed
+		v := JudgeAnswers(q, intended, row.answers, revisions, map[string]bool{"anchor": true}, row.pulsing, at)
+		all := strings.Join(append(append([]string{}, v.Fails...), v.Notes...), "; ")
+		if v.State != row.state || !strings.Contains(all, row.words) {
+			t.Errorf("%s: %s, %q", row.name, v.State, all)
+		}
+		if row.seed && row.state == delivery.VerdictPass && !strings.Contains(Brief(q, v), "the seed carries: node-tools: MESH_OWNED_PATHS[/etc/resolv.conf] networkmanager (node-uplink) → (value cut) (and 1 more fields)") {
+			t.Errorf("%s: the brief does not name it: %s", row.name, Brief(q, v))
+		}
+		if row.seed && row.state == delivery.VerdictPass {
+			whole := row.answers["laptop"].Differs[0]
+			whole.Bodies = []delivery.ResourceBodies{{ID: "r", Paths: []string{"env.MESH_OWNED_PATHS./etc/resolv.conf"},
+				Running:  `{"env":{"MESH_OWNED_PATHS":"{\"/etc/resolv.conf\":\"networkmanager (node-uplink)\"}"}}`,
+				Composed: `{"env":{"MESH_OWNED_PATHS":"{\"/etc/resolv.conf\":\"systemd-resolved (node-resolver)\"}"}}`}}
+			if got := differenceWords(whole); got != "node-tools: MESH_OWNED_PATHS[/etc/resolv.conf] networkmanager (node-uplink) → systemd-resolved (node-resolver)" {
+				t.Errorf("the difference is named %q", got)
+			}
+		}
+		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays as today: spiegel (held)") {
+			t.Errorf("%s: the brief does not show it: %s", row.name, Brief(q, v))
+		}
+		if row.marked != "" && (!slices.Contains(v.Unintended["anchor"], row.marked) || !strings.Contains(Brief(q, v), "not computed: "+row.marked)) {
+			t.Errorf("%s: the difference is not marked: %+v, %s", row.name, v.Unintended, Brief(q, v))
+		}
+	}
+}

modules/mesh-delivery-assigner/manifest_test.go

@@ -33,9 +33,11 @@ func TestManifest(t *testing.T) {
 	}
 	reads := slices.Clone(m.Reads)
 	slices.Sort(reads)
-	want := []string{"mesh-build-go.steps", "mesh-config.kept", "mesh-config.resolved",
-		"mesh-delivery-builder.build-log", "mesh-delivery-builder.builds", "mesh-delivery-indexer.candidates", "mesh-delivery-indexer.manifests",
-		"mesh-delivery-indexer.modules", "mesh-delivery-teller.answers", "mesh-delivery-watchman.presence", "mesh-grants.grants", "mesh-provisioner.provisions", "node-engine.have"}
+	// ADR 0593 §8: it composes nothing, so it reads no candidate, held or resolved value, compose step or build log; it reads
+	// every node's published compositions to compare them.
+	want := []string{"mesh-delivery-builder.builds", "mesh-delivery-indexer.manifests", "mesh-delivery-indexer.modules",
+		"mesh-delivery-teller.answers", "mesh-delivery-watchman.presence", "mesh-grants.grants", "mesh-host.composed",
+		"mesh-provisioner.provisions", "node-engine.have"}
 	if !reflect.DeepEqual(reads, want) {
 		t.Errorf("reads = %v, want exactly %v", reads, want)
 	}
@@ -43,7 +45,7 @@ func TestManifest(t *testing.T) {
 	for _, s := range m.State {
 		states[s.Name] = s.History
 	}
-	if want := map[string]int{"asks": 5, "compositions": 5, "differences": 64, "puts": 20, "wants": 20,
+	if want := map[string]int{"asks": 5, "differences": 64, "puts": 20, "wants": 20,
 		"placement": 64, "proposals": 5, "candidates": 5, "pulses": 0, "findings": 5, "policies": 20, "seat-holders": 5}; !reflect.DeepEqual(states, want) {
 		t.Errorf("state = %v, want %v", states, want)
 	}
@@ -53,10 +55,10 @@ func TestManifest(t *testing.T) {
 	if m.SecretsOwner != "mesh-delivery-assigner" {
 		t.Errorf("secrets-owner = %q", m.SecretsOwner)
 	}
-	// 1906/D3: it says its conditions on the operator channel; 1622: it puts its compose asks on the Go build seat, as the
-	// checker puts its checks.
-	if !slices.Equal(m.Uses, []string{"node-build-go", "operator-channel"}) {
-		t.Errorf("uses = %v, want exactly node-build-go and operator-channel", m.Uses)
+	// 1906/D3: it says its conditions on the operator channel; it asks the Go build seat nothing since the composition is
+	// the node-engine's (ADR 0593 §7).
+	if !slices.Equal(m.Uses, []string{"operator-channel"}) {
+		t.Errorf("uses = %v, want exactly operator-channel", m.Uses)
 	}
 	// ADR 0546: it serves its own tools (put, release, puts) from its bundle through the tool runner (the artifact loads the
 	// module), says each put's step as the event put, and calls the hand-act seat and the bus node's backup holder.

modules/mesh-delivery-assigner/module.json

@@ -24,22 +24,17 @@
     }
   ],
   "reads": [
-    "mesh-build-go.steps",
-    "mesh-config.kept",
-    "mesh-config.resolved",
-    "mesh-delivery-builder.build-log",
     "mesh-delivery-builder.builds",
-    "mesh-delivery-indexer.candidates",
     "mesh-delivery-indexer.manifests",
     "mesh-delivery-indexer.modules",
     "mesh-delivery-teller.answers",
     "mesh-delivery-watchman.presence",
     "mesh-grants.grants",
+    "mesh-host.composed",
     "mesh-provisioner.provisions",
     "node-engine.have"
   ],
   "uses": [
-    "node-build-go",
     "operator-channel"
   ],
   "invokes": [
@@ -63,7 +58,6 @@
     { "name": "candidates", "history": 5 },
     { "name": "pulses", "key-ttl": true },
     { "name": "asks", "history": 5 },
-    { "name": "compositions", "history": 5 },
     { "name": "differences", "history": 64 },
     { "name": "puts", "history": 20 },
     { "name": "wants", "history": 20 },

modules/mesh-delivery-builder/buildrun/asks.go

@@ -0,0 +1,316 @@
+package buildrun
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **An asker puts an ask on its build seat's stream and waits for its step** (novox/hq ADR 0525 §1, §6; issue 1887 A4,
+// A5). It chooses no node: whichever build node pulls the ask writes `<node>.<ask id>` in its build module's steps state,
+// and the asker reads the first such key that is not running. The builder and the checker share it.
+
+// AskPublisher puts an encoded ask on subject, de-duplicated by its id.
+type AskPublisher interface {
+	PublishAsk(ctx context.Context, subject, id string, data []byte) error
+}
+
+// AskWaiter watches an ask's steps: every value a key `*.<ask id>` of the build module's steps state takes, running or
+// ended, on the channel it answers, until ctx ends. A watch, not a poll.
+type AskWaiter interface {
+	WatchAsk(ctx context.Context, module, askID string) (<-chan delivery.Step, error)
+}
+
+// Asker puts asks and waits for their steps.
+type Asker struct {
+	Publisher AskPublisher
+	Waiter    AskWaiter
+	// Bound is how long a running step (a build node took the ask, its key written running) may stand still, with no new phase,
+	// before the asker stops waiting; a step that keeps moving is waited for up to 3 Bounds from its start (issue 1930); zero waits as long as ctx. An ask waiting in its stream is not bounded: the stream's backlog is no fault
+	// (ADR 0525 §6, §9), and the bound starts again when another node takes the ask.
+	Bound time.Duration
+}
+
+// Put puts a on its stream: the seat's accept subject of its language and kind.
+func (k Asker) Put(ctx context.Context, a delivery.StepAsk) error {
+	raw, err := delivery.EncodeStepAsk(a)
+	if err != nil {
+		return err
+	}
+	subject, err := delivery.AskSubject(a.Language, a.Kind)
+	if err != nil {
+		return err
+	}
+	if err := k.Publisher.PublishAsk(ctx, subject, a.ID, raw); err != nil {
+		return fmt.Errorf("putting the %s ask %s: %w", a.Kind, a.ID, err)
+	}
+	return nil
+}
+
+// Wait waits for the step of an ask already put (a builder that started again takes over its own asks with it, never
+// putting them twice) and answers it when it ended, whatever its state. The bound runs from the step's start on the node
+// that took the ask, read from its running key, so an ask that waits in the stream for a free slot waits as long as ctx.
+func (k Asker) Wait(ctx context.Context, a delivery.StepAsk) (delivery.Step, error) {
+	module, err := delivery.BuildModuleOf(a.Language)
+	if err != nil {
+		return delivery.Step{}, err
+	}
+	watch, cancel := context.WithCancel(ctx)
+	defer cancel()
+	steps, err := k.Waiter.WatchAsk(watch, module, a.ID)
+	if err != nil {
+		return delivery.Step{}, err
+	}
+	var bound, outerCap <-chan time.Time
+	var timer, capTimer *time.Timer
+	defer func() {
+		if timer != nil {
+			timer.Stop()
+		}
+		if capTimer != nil {
+			capTimer.Stop()
+		}
+	}()
+	running, since, phase, phaseAt := "", time.Time{}, "", time.Time{}
+	standStill := func() error {
+		if phase == "" {
+			return fmt.Errorf("the ask %s's step on %s did not end within %s of its start: it stood still, saying no phase", a.ID, running, k.Bound)
+		}
+		return fmt.Errorf("the ask %s's step on %s did not end within %s: it stood still in %q since %s",
+			a.ID, running, k.Bound, phase, phaseAt.UTC().Format(time.RFC3339))
+	}
+	for {
+		select {
+		case <-ctx.Done():
+			return delivery.Step{}, ctx.Err()
+		case <-bound:
+			return delivery.Step{}, standStill()
+		case <-outerCap:
+			return delivery.Step{}, fmt.Errorf("the ask %s's step on %s did not end within %s of its start: it kept moving (last phase %q at %s) but never ended",
+				a.ID, running, 3*k.Bound, phase, phaseAt.UTC().Format(time.RFC3339))
+		case step, ok := <-steps:
+			if !ok {
+				return delivery.Step{}, errors.New("the watch of the ask's step ended")
+			}
+			if seen := stepSeenOf(ctx); seen != nil {
+				seen(step)
+			}
+			if step.State != delivery.StepRunning {
+				return step, nil
+			}
+			if k.Bound <= 0 {
+				continue
+			}
+			newRun := step.Node != running || !step.Started.Equal(since)
+			if !newRun && step.Phase == phase && step.PhaseAt.Equal(phaseAt) {
+				continue
+			}
+			// A node took the ask, or took it again after its run stopped (another node, or the same node's build module
+			// replaced mid-run: a new start), or its step entered a phase. The bound is on standing still: it runs from the
+			// step's last movement (its phase's start, else its start), so a step that keeps moving is waited for, up to
+			// three bounds from its start (issue 1930).
+			running, since, phase, phaseAt = step.Node, step.Started, step.Phase, step.PhaseAt
+			last := step.Started
+			if step.PhaseAt.After(last) {
+				last = step.PhaseAt
+			}
+			left := k.Bound
+			if !last.IsZero() {
+				left = time.Until(last.Add(k.Bound))
+			}
+			if timer != nil {
+				timer.Stop()
+			}
+			timer = time.NewTimer(max(left, 0))
+			bound = timer.C
+			if newRun {
+				if capTimer != nil {
+					capTimer.Stop()
+				}
+				outer := 3 * k.Bound
+				if !step.Started.IsZero() {
+					outer = time.Until(step.Started.Add(3 * k.Bound))
+				}
+				capTimer = time.NewTimer(max(outer, 0))
+				outerCap = capTimer.C
+			}
+		}
+	}
+}
+
+type stepSeenKey struct{}
+
+// WithStepSeen is ctx carrying seen, which Asker.Wait hands every value the ask's step key takes while it waits: the node
+// that took it, each phase it says while running (delivery.Step.Phase), and its end. A try names its asks' progress so
+// (issue 1890). seen runs in the waiting goroutine and must not block.
+func WithStepSeen(ctx context.Context, seen func(delivery.Step)) context.Context {
+	return context.WithValue(ctx, stepSeenKey{}, seen)
+}
+
+func stepSeenOf(ctx context.Context) func(delivery.Step) {
+	seen, _ := ctx.Value(stepSeenKey{}).(func(delivery.Step))
+	return seen
+}
+
+// Ask puts a and waits for its step; a step that did not pass is an error naming its node, its state and its reason.
+func (k Asker) Ask(ctx context.Context, a delivery.StepAsk) (delivery.Step, error) {
+	if err := k.Put(ctx, a); err != nil {
+		return delivery.Step{}, err
+	}
+	return k.Passed(k.Wait(ctx, a))
+}
+
+// Passed is step when it passed, else an error naming where it ended and why.
+func (k Asker) Passed(step delivery.Step, err error) (delivery.Step, error) {
+	if err != nil {
+		return step, err
+	}
+	if step.State != delivery.StepPassed {
+		return step, fmt.Errorf("the ask %s on %s %s: %s", step.ID, step.Node, step.State, step.Reason)
+	}
+	return step, nil
+}
+
+// JetStreamAsks is the bus side of an Asker: a JetStream publish de-duplicated by the ask's id (Nats-Msg-Id), and a watch
+// of `*.<ask id>` in the build module's steps bucket.
+type JetStreamAsks struct {
+	JS jetstream.JetStream
+}
+
+// PublishAsk is AskPublisher's.
+func (s JetStreamAsks) PublishAsk(ctx context.Context, subject, id string, data []byte) error {
+	msg := &nats.Msg{Subject: subject, Data: data, Header: nats.Header{}}
+	msg.Header.Set(jetstream.MsgIDHeader, id)
+	_, err := s.JS.PublishMsg(ctx, msg)
+	return err
+}
+
+// WatchAsk is AskWaiter's: the watch hands over what the keys hold now, so a step that ended before it began is read at
+// once, and every change after.
+func (s JetStreamAsks) WatchAsk(ctx context.Context, module, askID string) (<-chan delivery.Step, error) {
+	pattern, err := delivery.AskStepWatch(askID)
+	if err != nil {
+		return nil, err
+	}
+	kv, err := s.JS.KeyValue(ctx, delivery.StepsBucket(module))
+	if err != nil {
+		return nil, fmt.Errorf("the bucket %s: %w", delivery.StepsBucket(module), err)
+	}
+	w, err := kv.Watch(ctx, pattern)
+	if err != nil {
+		return nil, err
+	}
+	out := make(chan delivery.Step)
+	go func() {
+		defer close(out)
+		defer w.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case e, ok := <-w.Updates():
+				if !ok {
+					return
+				}
+				if e == nil || e.Operation() != jetstream.KeyValuePut {
+					continue
+				}
+				step, err := delivery.DecodeStep(e.Value())
+				if err != nil {
+					continue // not a step (a node's pause key never matches an ask id; anything else is not this ask's)
+				}
+				select {
+				case out <- step:
+				case <-ctx.Done():
+					return
+				}
+			}
+		}
+	}()
+	return out, nil
+}
+
+// FakeAsks is a test double of the bus for an asker's tests: each ask put is kept and, when Answer is set, its step is
+// written at once with what Answer says a build node wrote (running or ended). Write writes a step later. Safe for
+// concurrent use.
+type FakeAsks struct {
+	Answer func(a delivery.StepAsk) delivery.Step
+
+	mu       sync.Mutex
+	asks     []delivery.StepAsk
+	steps    map[string][]delivery.Step
+	watchers map[string][]chan delivery.Step
+}
+
+// PublishAsk is AskPublisher's.
+func (f *FakeAsks) PublishAsk(_ context.Context, _, id string, data []byte) error {
+	a, err := delivery.DecodeStepAsk(data)
+	if err != nil {
+		return err
+	}
+	f.mu.Lock()
+	f.asks = append(f.asks, a)
+	f.mu.Unlock()
+	if f.Answer != nil {
+		f.Write(f.Answer(a))
+	}
+	return nil
+}
+
+// Write writes an ask's step, as a build node does.
+func (f *FakeAsks) Write(step delivery.Step) {
+	f.mu.Lock()
+	if f.steps == nil {
+		f.steps, f.watchers = map[string][]delivery.Step{}, map[string][]chan delivery.Step{}
+	}
+	f.steps[step.ID] = append(f.steps[step.ID], step)
+	ws := append([]chan delivery.Step(nil), f.watchers[step.ID]...)
+	f.mu.Unlock()
+	for _, w := range ws {
+		w <- step
+	}
+}
+
+// End is Write: kept for the tests that end a step.
+func (f *FakeAsks) End(step delivery.Step) { f.Write(step) }
+
+// WatchAsk is AskWaiter's: what was written so far, then every write.
+func (f *FakeAsks) WatchAsk(ctx context.Context, _ string, askID string) (<-chan delivery.Step, error) {
+	out := make(chan delivery.Step, 64)
+	f.mu.Lock()
+	if f.steps == nil {
+		f.steps, f.watchers = map[string][]delivery.Step{}, map[string][]chan delivery.Step{}
+	}
+	for _, s := range f.steps[askID] {
+		out <- s
+	}
+	f.watchers[askID] = append(f.watchers[askID], out)
+	f.mu.Unlock()
+	go func() {
+		<-ctx.Done()
+		f.mu.Lock()
+		ws := f.watchers[askID]
+		for i, w := range ws {
+			if w == out {
+				f.watchers[askID] = append(ws[:i], ws[i+1:]...)
+				break
+			}
+		}
+		f.mu.Unlock()
+	}()
+	return out, nil
+}
+
+// Asks are the asks put so far.
+func (f *FakeAsks) Asks() []delivery.StepAsk {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return append([]delivery.StepAsk(nil), f.asks...)
+}

modules/mesh-delivery-builder/buildrun/asks_integration_test.go

@@ -0,0 +1,61 @@
+//go:build integration
+
+package buildrun
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/testbus"
+)
+
+// 1887/A4a, 1887/AC3 on the real bus: an ask put twice under one id is one message, and the asker reads the step a node
+// wrote under `<node>.<ask id>`.
+func TestAnAskIsPutOnceAndItsStepIsRead(t *testing.T) {
+	nc, err := nats.Connect(testbus.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	js, _ := jetstream.New(nc)
+	ctx := context.Background()
+	if _, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "SEAT_NODE_BUILD_GO", Subjects: []string{"mesh.seat.node-build-go.accept.>"},
+		Retention: jetstream.WorkQueuePolicy}); err != nil {
+		t.Fatal(err)
+	}
+	kv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: delivery.StepsBucket("mesh-build-go")})
+	if err != nil {
+		t.Fatal(err)
+	}
+	bus := JetStreamAsks{JS: js}
+	k := Asker{Publisher: bus, Waiter: bus, Bound: 5 * time.Second}
+	a := goAsk("mvl0frv18d1960")
+	for i := 0; i < 2; i++ {
+		if err := k.Put(ctx, a); err != nil {
+			t.Fatal(err)
+		}
+	}
+	s, _ := js.Stream(ctx, "SEAT_NODE_BUILD_GO")
+	if info, _ := s.Info(ctx); info.State.Msgs != 1 {
+		t.Fatalf("%d messages for one ask put twice", info.State.Msgs)
+	}
+	go func() {
+		time.Sleep(100 * time.Millisecond)
+		key, _ := delivery.AskStepKey("ace", a.ID)
+		running, _ := delivery.EncodeStep(delivery.Step{ID: a.ID, Tool: "delivery ask", Node: "ace", State: delivery.StepRunning, Started: time.Now()})
+		_, _ = kv.Put(ctx, key, running)
+		passed, _ := delivery.EncodeStep(delivery.Step{ID: a.ID, Tool: "delivery ask", Node: "ace", State: delivery.StepPassed, Started: time.Now(),
+			Result: json.RawMessage(`{"artifacts":[]}`)})
+		_, _ = kv.Put(ctx, key, passed)
+	}()
+	step, err := k.Passed(k.Wait(ctx, a))
+	if err != nil || step.Node != "ace" {
+		t.Fatalf("step %+v, %v", step, err)
+	}
+}

modules/mesh-delivery-builder/buildrun/asks_test.go

@@ -0,0 +1,250 @@
+package buildrun
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/health"
+)
+
+func goAsk(id string) delivery.StepAsk {
+	return delivery.StepAsk{ID: id, Kind: delivery.AskDelivery, Language: delivery.AskGo, Asker: "mesh-delivery-builder", At: time.Now(),
+		Build: &delivery.BuildJob{Module: "m", Path: ".", Fetch: map[string]any{"repository": "novox/x", "commit": strings.Repeat("a", 40)},
+			Artifacts: []delivery.AskArtifact{{Artifact: "program"}}}}
+}
+
+// 1887/A4a: an asker puts the ask once and answers the step a build node wrote for it, naming the node; one that did not
+// pass is an error naming the node and why; a wait of an ask already put puts nothing.
+func TestAnAskerPutsOnceAndReadsTheStep(t *testing.T) {
+	f := &FakeAsks{Answer: func(a delivery.StepAsk) delivery.Step {
+		return delivery.Step{ID: a.ID, Node: "ace", State: delivery.StepPassed, Result: []byte(`{"artifacts":[]}`)}
+	}}
+	k := Asker{Publisher: f, Waiter: f}
+	var seen []delivery.Step // issue 1890: a waiter that asks to see each value of the step sees it
+	step, err := k.Ask(WithStepSeen(context.Background(), func(s delivery.Step) { seen = append(seen, s) }), goAsk("mvl0frv18d1957"))
+	if err != nil || step.Node != "ace" || len(f.Asks()) != 1 || len(seen) != 1 || seen[0].Node != "ace" {
+		t.Fatalf("step %+v, %v, asks %d, seen %+v", step, err, len(f.Asks()), seen)
+	}
+	f.Answer = func(a delivery.StepAsk) delivery.Step {
+		return delivery.Step{ID: a.ID, Node: "shanks", State: delivery.StepRefused, Reason: "go 1.27 installed"}
+	}
+	if _, err := k.Ask(context.Background(), goAsk("mvl0frv18d1958")); err == nil || !strings.Contains(err.Error(), "shanks refused: go 1.27 installed") {
+		t.Fatalf("a refused step: %v", err)
+	}
+	// review round 2 item 1: an ask that waits in its stream for a free slot is not bounded; once a node writes its step
+	// running, the step is bounded from its start, and the error names the node.
+	g := &FakeAsks{}
+	k = Asker{Publisher: g, Waiter: g, Bound: 20 * time.Millisecond}
+	waiting, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+	if _, err := k.Wait(waiting, goAsk("mvl0frv18d1959")); err != context.DeadlineExceeded {
+		t.Fatalf("an ask no node took: %v, want it still waiting when ctx ended", err)
+	}
+	g.Write(delivery.Step{ID: "mvl0frv18d1961", Node: "ace", State: delivery.StepRunning, Started: time.Now()})
+	if _, err := k.Wait(context.Background(), goAsk("mvl0frv18d1961")); err == nil || !strings.Contains(err.Error(), "on ace did not end within") {
+		t.Fatalf("a step that never ends: %v", err)
+	}
+	if len(g.Asks()) != 0 {
+		t.Fatal("a wait put an ask")
+	}
+	// Issue 1930: the bound is on a step that stands still, not on its age. A step that enters a new phase inside the bound is
+	// waited for until it ends; one that stays in a phase the bound fails at once, naming the phase; one that never stops moving
+	// ends at three bounds, said as such.
+	k = Asker{Publisher: g, Waiter: g, Bound: 60 * time.Millisecond}
+	started := time.Now()
+	go func() {
+		for i := range 8 {
+			g.Write(delivery.Step{ID: "mvl0frv18d1980", Node: "ace", State: delivery.StepRunning, Started: started, Phase: "p" + string(rune('a'+i)), PhaseAt: time.Now()})
+			time.Sleep(15 * time.Millisecond)
+		}
+		g.Write(delivery.Step{ID: "mvl0frv18d1980", Node: "ace", State: delivery.StepPassed})
+	}()
+	if step, err := k.Wait(context.Background(), goAsk("mvl0frv18d1980")); err != nil || step.State != delivery.StepPassed {
+		t.Fatalf("a step that kept moving past its bound: %+v, %v", step, err)
+	}
+	g.Write(delivery.Step{ID: "mvl0frv18d1981", Node: "ace", State: delivery.StepRunning, Started: time.Now(), Phase: "integration: tests", PhaseAt: time.Now()})
+	if _, err := k.Wait(context.Background(), goAsk("mvl0frv18d1981")); err == nil || !strings.Contains(err.Error(), `stood still in "integration: tests"`) {
+		t.Fatalf("a step that stood still in a phase: %v", err)
+	}
+	loop := make(chan struct{})
+	defer close(loop)
+	started = time.Now()
+	go func() {
+		for i := 0; ; i++ {
+			select {
+			case <-loop:
+				return
+			case <-time.After(20 * time.Millisecond):
+				g.Write(delivery.Step{ID: "mvl0frv18d1982", Node: "ace", State: delivery.StepRunning, Started: started, Phase: "q" + string(rune('a'+i%26)), PhaseAt: time.Now()})
+			}
+		}
+	}()
+	if _, err := k.Wait(context.Background(), goAsk("mvl0frv18d1982")); err == nil || !strings.Contains(err.Error(), "kept moving") {
+		t.Fatalf("a step that never stops moving: %v", err)
+	}
+	// Issue 734: an ask the build seat gave up on (DEAD_LETTERS keeps its copy with the ask's id) ends its wait as failed
+	// with the words, though a node had taken it; under NotTakenBound one no node takes ends at the bound; a step written
+	// first is answered as the node wrote it.
+	dead := &DeadLetters{}
+	lw := LostAskWaiter{Inner: g, Dead: dead}
+	k = Asker{Publisher: g, Waiter: lw, Bound: time.Minute}
+	g.Write(delivery.Step{ID: "mvl0frv18d1970", Node: "ace", State: delivery.StepRunning, Started: time.Now()})
+	given, ok := GivenUpOf(map[string][]string{"Mesh-Dead-Msg-Id": {"mvl0frv18d1970"}, "Mesh-Dead-Deliveries": {"5"},
+		"Mesh-Dead-Stream": {"SEAT_NODE_BUILD_GO"}, "Mesh-Dead-Gave-Up": {"2026-10-26T12:26:40Z"}})
+	if !ok {
+		t.Fatal("a dead letter's headers were not read")
+	}
+	go dead.Heard(given)
+	step, err = k.Wait(context.Background(), goAsk("mvl0frv18d1970"))
+	if err != nil || step.State != delivery.StepFailed || !IsLost(step) ||
+		!strings.Contains(step.Reason, LostWords+" after 5 deliveries at 2026-10-26T12:26:40Z") {
+		t.Fatalf("a given-up ask: %+v, %v", step, err)
+	}
+	if _, err := k.Passed(step, nil); err == nil || !strings.Contains(err.Error(), "on "+LostNode+" failed: "+LostWords) {
+		t.Fatalf("a given-up ask's error: %v", err)
+	}
+	step, err = k.Wait(NotTakenBound(context.Background(), 20*time.Millisecond), goAsk("mvl0frv18d1971"))
+	if err != nil || !IsNotTaken(step) || IsLost(step) {
+		t.Fatalf("an ask no node took: %+v, %v", step, err)
+	}
+	g.Write(delivery.Step{ID: "mvl0frv18d1972", Node: "g14", State: delivery.StepPassed})
+	if step, err = k.Wait(NotTakenBound(context.Background(), time.Minute), goAsk("mvl0frv18d1972")); err != nil || step.Node != "g14" {
+		t.Fatalf("a step written: %+v, %v", step, err)
+	}
+	// Review round 1 of issue 734: a hearing the bus refuses at start is deaf and says so, never holds the start up, and
+	// tries again on the next ask waited for; heard, it says so and hands the given-up asks on.
+	fol := &refusingFollower{refuse: 1}
+	var mu sync.Mutex
+	var told []Hearing
+	hearing := NewDeadLetterHearing(context.Background(), fol, []string{delivery.AskGo}, dead, nil,
+		func(h Hearing) { mu.Lock(); told = append(told, h); mu.Unlock() })
+	hearing.Wait()
+	if why := hearing.Deaf(); !strings.Contains(why, "SEAT_NODE_BUILD_GO: permissions violation") {
+		t.Fatalf("a refused hearing says %q", why)
+	}
+	k = Asker{Publisher: g, Waiter: LostAskWaiter{Inner: g, Dead: dead, Hearing: hearing}, Bound: time.Minute}
+	g.Write(delivery.Step{ID: "mvl0frv18d1973", Node: "g14", State: delivery.StepPassed})
+	if _, err := k.Wait(context.Background(), goAsk("mvl0frv18d1973")); err != nil {
+		t.Fatal(err)
+	}
+	hearing.Wait()
+	mu.Lock()
+	if hearing.Deaf() != "" || len(told) != 2 || told[0].Heard || !told[1].Heard || fol.calls() != 2 {
+		t.Fatalf("after an ask: deaf %q, told %+v, followed %d times", hearing.Deaf(), told, fol.calls())
+	}
+	mu.Unlock()
+	fol.heard(GivenUp{AskID: "mvl0frv18d1974", Deliveries: 5})
+	step, err = k.Wait(context.Background(), goAsk("mvl0frv18d1974"))
+	if err != nil || !IsLost(step) {
+		t.Fatalf("an ask heard given up after the hearing came back: %+v, %v", step, err)
+	}
+	// The lost check of 2026-10-28: a step whose own watch went deaf is read at the next nudge (a step of its build module
+	// ended) and answered; a nudge of another build module reads nothing; a watch that closes is opened again.
+	d := &FakeAsks{}
+	heard := &HeardEnds{Inner: deafWatch{}, Read: d}
+	k = Asker{Publisher: d, Waiter: heard, Bound: time.Minute}
+	d.Write(delivery.Step{ID: "mvl0frv18d1980", Node: "shanks", State: delivery.StepPassed})
+	got := make(chan delivery.Step, 1)
+	go func() { s, _ := k.Wait(context.Background(), goAsk("mvl0frv18d1980")); got <- s }()
+	for heard.Waiting() == 0 {
+		time.Sleep(time.Millisecond)
+	}
+	heard.Nudge(NodeBuildModule)
+	select {
+	case s := <-got:
+		t.Fatalf("a nudge of another build module answered %+v", s)
+	case <-time.After(20 * time.Millisecond):
+	}
+	heard.Nudge(GoBuildModule)
+	if s := <-got; s.State != delivery.StepPassed || s.Node != "shanks" {
+		t.Fatalf("a step its watch never handed over: %+v", s)
+	}
+	closing := &HeardEnds{Inner: &closingWatch{inner: d}, Read: d}
+	if s, err := (Asker{Publisher: d, Waiter: closing}).Wait(context.Background(), goAsk("mvl0frv18d1980")); err != nil || s.State != delivery.StepPassed {
+		t.Fatalf("a watch that closed once: %+v, %v", s, err)
+	}
+	for _, row := range []struct {
+		h    *Hearing
+		want string
+	}{{nil, health.StateUnhealthy}, {&told[0], health.StateUnhealthy}, {&told[1], health.StateHealthy}} {
+		var raw []byte
+		if row.h != nil {
+			raw, _ = json.Marshal(row.h)
+		}
+		if a := HearingHealth(raw); a.State != row.want || a.Why == "" {
+			t.Errorf("health of %+v = %+v, want %s", row.h, a, row.want)
+		}
+	}
+}
+
+// Review (issue 734 path): an ask taken again by the same node (its build module replaced mid-run) is bounded from the
+// new run's start, so its pass is answered after the first run's bound would have ended the wait.
+func TestARedeliveryToTheSameNodeRestartsTheBound(t *testing.T) {
+	f := &FakeAsks{}
+	k := Asker{Publisher: f, Waiter: f, Bound: 60 * time.Millisecond}
+	const id = "mvl0frv18d1962"
+	first := time.Now()
+	f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepRunning, Started: first})
+	go func() {
+		time.Sleep(15 * time.Millisecond)
+		f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepRunning, Started: time.Now()})
+		time.Sleep(50 * time.Millisecond) // past the first run's bound, inside the second's
+		f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepPassed, Started: time.Now()})
+	}()
+	step, err := k.Wait(context.Background(), goAsk(id))
+	if err != nil || step.State != delivery.StepPassed {
+		t.Fatalf("step %+v, %v, want the redelivered run's pass", step, err)
+	}
+}
+
+// refusingFollower refuses the first `refuse` follows, as the bus does before the asker's grant is composed.
+type refusingFollower struct {
+	mu     sync.Mutex
+	refuse int
+	n      int
+	hand   func(GivenUp)
+}
+
+func (f *refusingFollower) Follow(_ context.Context, _ string, _ time.Time, heard func(GivenUp)) (func(), error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.n++
+	if f.n <= f.refuse {
+		return nil, errors.New("permissions violation")
+	}
+	f.hand = heard
+	return func() {}, nil
+}
+
+func (f *refusingFollower) calls() int { f.mu.Lock(); defer f.mu.Unlock(); return f.n }
+
+func (f *refusingFollower) heard(g GivenUp) { f.mu.Lock(); h := f.hand; f.mu.Unlock(); h(g) }
+
+// deafWatch is a watch of an ask's step that stays open and hears nothing.
+type deafWatch struct{}
+
+func (deafWatch) WatchAsk(context.Context, string, string) (<-chan delivery.Step, error) {
+	return make(chan delivery.Step), nil
+}
+
+// closingWatch closes its first watch at once, and hands the later ones to inner.
+type closingWatch struct {
+	inner  AskWaiter
+	closed bool
+}
+
+func (c *closingWatch) WatchAsk(ctx context.Context, module, askID string) (<-chan delivery.Step, error) {
+	if !c.closed {
+		c.closed = true
+		ch := make(chan delivery.Step)
+		close(ch)
+		return ch, nil
+	}
+	return c.inner.WatchAsk(ctx, module, askID)
+}

modules/mesh-delivery-builder/buildrun/choose.go

@@ -0,0 +1,88 @@
+package buildrun
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// ChooseNodes picks up to want build nodes for a language (ADR 0478 clause 3): the nodes whose toolchains key reports the
+// version the nodes agree on, the ones with room under their build capacity first (places), then the fewest lanes the
+// part has running or chosen there, a tie broken by the node's name. A place is reserved on each node chosen, in the
+// same step as the choice, so builds choosing at once do not choose the same full node while another has room; the
+// caller takes the place (Places.Acquire) or gives it up (Places.Cancel). A node at its capacity is still chosen when
+// the others are too (fewer than want have room): its lane waits for a place. A node qualifies only when qualifies is true
+// of it (online and its build module healthy; nil means every node does). It answers the toolchain all the reporting nodes
+// agree on, qualifying or not, as the indexer computes it. When nothing is reported, or the nodes report different
+// versions (so the indexer agreed none), it fails naming the language and why; when no reporting node qualifies it fails
+// naming the nodes. A node whose build module refuses on its toolchain refuses the step, and the build fails naming it.
+func ChooseNodes(language string, entries []delivery.NodeToolchain, places *Places, qualifies func(node string) bool, want int) ([]string, delivery.Toolchain2, error) {
+	tc, none := delivery.AgreedToolchain(entries)
+	if none != "" {
+		return nil, delivery.Toolchain2{}, fmt.Errorf("no %s build node qualifies: %s", language, none)
+	}
+	nodes, err := choose(language, entries, places, qualifies, want)
+	return nodes, tc, err
+}
+
+// ChooseAnyNodes is ChooseNodes for artifacts that need no toolchain, such as an archive (ADR 0478 clause 1): the
+// build module's nodes agree on nothing, so any node of the build module that qualifies is chosen, by capacity and load only.
+func ChooseAnyNodes(language string, entries []delivery.NodeToolchain, places *Places, qualifies func(node string) bool, want int) ([]string, error) {
+	return choose(language, entries, places, qualifies, want)
+}
+
+func choose(language string, entries []delivery.NodeToolchain, places *Places, qualifies func(node string) bool, want int) ([]string, error) {
+	if places == nil {
+		places = &Places{}
+	}
+	nodes := make([]string, 0, len(entries))
+	var reporting []string
+	seen := map[string]bool{}
+	for _, e := range entries {
+		if seen[e.Node] {
+			continue
+		}
+		seen[e.Node] = true
+		reporting = append(reporting, e.Node)
+		if places.CapacityOf(e.Node) > 0 && (qualifies == nil || qualifies(e.Node)) { // a capacity of 0 keeps the part off a node
+			nodes = append(nodes, e.Node)
+		}
+	}
+	if len(nodes) == 0 {
+		sort.Strings(reporting)
+		return nil, fmt.Errorf("no %s build node qualifies: %s report the toolchain, and none is online with a healthy build module and a build capacity", language, strings.Join(reporting, ", "))
+	}
+	return places.choose(nodes, want), nil
+}
+
+// DigestsDifferPrefix opens the error of a build whose nodes built an artifact to different digests (ADR 0478 clause 4):
+// such a key is not built again as a new revision, since the same source on the same toolchains gave two answers and
+// building again settles nothing; it waits for another fingerprint.
+const DigestsDifferPrefix = "digests differ:"
+
+// Agree is the one digest every node built an artifact to (ADR 0478 clause 4), or an error naming each node and its
+// digest when they differ. One node's digest agrees with itself.
+func Agree(artifact string, byNode map[string]string) (string, error) {
+	nodes := make([]string, 0, len(byNode))
+	for n := range byNode {
+		nodes = append(nodes, n)
+	}
+	sort.Strings(nodes)
+	var first string
+	for i, n := range nodes {
+		if i == 0 {
+			first = byNode[n]
+			continue
+		}
+		if byNode[n] != first {
+			msg := fmt.Sprintf("%s the nodes built %s to different digests:", DigestsDifferPrefix, artifact)
+			for _, n := range nodes {
+				msg += fmt.Sprintf(" %s %s;", n, byNode[n])
+			}
+			return "", fmt.Errorf("%s", msg[:len(msg)-1])
+		}
+	}
+	return first, nil
+}

modules/mesh-delivery-builder/buildrun/choose_test.go

@@ -0,0 +1,109 @@
+package buildrun
+
+import (
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+const digest = "sha256:2222222222222222222222222222222222222222222222222222222222222222"
+
+func hex64(c byte) string { return strings.Repeat(string(c), 64) }
+
+func tcs(language, version string, nodes ...string) []delivery.NodeToolchain {
+	var out []delivery.NodeToolchain
+	for _, n := range nodes {
+		out = append(out, delivery.NodeToolchain{Node: n, Toolchain: delivery.Toolchain{Language: language, Version: version, Recipe: "1"}})
+	}
+	return out
+}
+
+func chooseTakesTheAgreedNodesWithFewestRunningStepsTiesByName(t *testing.T) { // 1607/AC4, ADR 0478 clause 3
+	entries := tcs("go", "go1.27.1", "novox", "ace", "g14", "shanks")
+	nodes, tc, err := ChooseNodes("go", entries, placesRunning(map[string]int{"novox": 3, "ace": 1, "g14": 1, "shanks": 0}), nil, 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(nodes) != 2 || nodes[0] != "shanks" || nodes[1] != "ace" {
+		t.Errorf("nodes = %v, want [shanks ace]: fewest steps first, a tie by name", nodes)
+	}
+	if tc.Version != "go1.27.1" || tc.Recipe != "1" || tc.Language != "go" {
+		t.Errorf("toolchain = %+v", tc)
+	}
+}
+
+func chooseWithOneNodeAnswersOneNode(t *testing.T) { // 1607/AC4
+	nodes, _, err := ChooseNodes("go", tcs("go", "go1.27.1", "novox"), nil, nil, 2)
+	if err != nil || len(nodes) != 1 || nodes[0] != "novox" {
+		t.Errorf("nodes = %v, err %v, want [novox]", nodes, err)
+	}
+}
+
+func chooseFailsNamingTheLanguageAndTheVersionsWhenNoNodeQualifies(t *testing.T) { // 1607/AC4
+	_, _, err := ChooseNodes("typescript", nil, nil, nil, 2)
+	if err == nil || !strings.Contains(err.Error(), "typescript") || !strings.Contains(err.Error(), delivery.ToolchainNoReport) {
+		t.Errorf("no report: error = %v, want it to name typescript and %q", err, delivery.ToolchainNoReport)
+	}
+	entries := append(tcs("go", "go1.27.1", "novox"), tcs("go", "go1.26.0", "ace")...)
+	_, _, err = ChooseNodes("go", entries, nil, nil, 2)
+	if err == nil || !strings.Contains(err.Error(), "go1.27.1") || !strings.Contains(err.Error(), "go1.26.0") || !strings.Contains(err.Error(), "go") {
+		t.Errorf("disagreeing nodes: error = %v, want both versions named", err)
+	}
+}
+
+func agreeNeedsEqualDigestsAndNamesBothNodesWhenTheyDiffer(t *testing.T) { // 1607/AC4, ADR 0478 clause 4
+	d, err := Agree("tool", map[string]string{"ace": digest, "novox": digest})
+	if err != nil || d != digest {
+		t.Errorf("Agree = %q, %v, want %q", d, err, digest)
+	}
+	_, err = Agree("tool", map[string]string{"ace": digest, "novox": "sha256:" + hex64('9')})
+	if err == nil || !strings.Contains(err.Error(), "ace") || !strings.Contains(err.Error(), "novox") || !strings.Contains(err.Error(), digest) || !strings.Contains(err.Error(), hex64('9')) || !strings.Contains(err.Error(), "tool") {
+		t.Errorf("differing digests: error = %v, want the artifact, both nodes and both digests", err)
+	}
+	if d, err := Agree("tool", map[string]string{"ace": digest}); err != nil || d != digest {
+		t.Errorf("one node: %q, %v", d, err)
+	}
+}
+
+func chooseSkipsNodesThatAreNotOnlineAndFailsNamingThemWhenNoneIs(t *testing.T) { // 1607 review 3, ADR 0478 clause 3
+	entries := tcs("go", "go1.27.1", "ace", "g14", "novox")
+	online := func(n string) bool { return n != "g14" } // a sleeping laptop
+	nodes, tc, err := ChooseNodes("go", entries, placesRunning(map[string]int{"novox": 5}), online, 2)
+	if err != nil || len(nodes) != 2 || nodes[0] != "ace" || nodes[1] != "novox" || tc.Version != "go1.27.1" {
+		t.Errorf("nodes = %v, toolchain %+v, err %v, want [ace novox] with g14 left out although it runs nothing", nodes, tc, err)
+	}
+	_, tc, err = ChooseNodes("go", entries, nil, func(string) bool { return false }, 2)
+	if err == nil || !strings.Contains(err.Error(), "online") || !strings.Contains(err.Error(), "g14") || !strings.Contains(err.Error(), "go") {
+		t.Errorf("none online: error = %v, want it to name the nodes that report and that none is online", err)
+	}
+	if tc.Version != "go1.27.1" {
+		t.Errorf("none online: the agreed toolchain %+v is still answered", tc)
+	}
+}
+
+// placesRunning is Places with these steps counted as running, for a test of the choice.
+func placesRunning(running map[string]int) *Places {
+	return &Places{running: running, changed: make(chan struct{})}
+}
+
+func choosePrefersNodesBelowTheirCapacity(t *testing.T) { // round 3
+	entries := tcs("go", "go1.27.1", "ace", "novox", "shanks")
+	// shanks has capacity 3 with 2 running: room; ace has the default 1 with 1 running: none; novox has none running.
+	p := placesRunning(map[string]int{"shanks": 2, "ace": 1})
+	p.Capacity = map[string]int{"shanks": 3}
+	nodes, _, err := ChooseNodes("go", entries, p, nil, 2)
+	if err != nil || len(nodes) != 2 || nodes[0] != "novox" || nodes[1] != "shanks" {
+		t.Errorf("nodes = %v, err %v, want [novox shanks]: the nodes with room, ace at capacity left out", nodes, err)
+	}
+}
+
+// The choice of the nodes a step runs on and the agreement of their answers, one table of cases (the test budget).
+func TestChoosingTheNodesOfAStep(t *testing.T) {
+	t.Run("choose takes the agreed nodes with fewest running steps ties by name", chooseTakesTheAgreedNodesWithFewestRunningStepsTiesByName)
+	t.Run("choose with one node answers one node", chooseWithOneNodeAnswersOneNode)
+	t.Run("choose fails naming the language and the versions when no node qualifies", chooseFailsNamingTheLanguageAndTheVersionsWhenNoNodeQualifies)
+	t.Run("agree needs equal digests and names both nodes when they differ", agreeNeedsEqualDigestsAndNamesBothNodesWhenTheyDiffer)
+	t.Run("choose skips nodes that are not online and fails naming them when none is", chooseSkipsNodesThatAreNotOnlineAndFailsNamingThemWhenNoneIs)
+	t.Run("choose prefers nodes below their capacity", choosePrefersNodesBelowTheirCapacity)
+}

modules/mesh-delivery-builder/buildrun/doc.go

@@ -0,0 +1,5 @@
+// Package buildrun holds the parts every module that runs steps on the build modules shares: the caller, the steps
+// watch and the runner of a long step (ADR 0469), the sets of presence, toolchains and healthy build modules, the
+// places a node offers by capacity, and the choice of build nodes (ADR 0478). The builder and the checker of the
+// delivery use them; they moved here from the builder's own package so neither keeps a copy (issue 1671, ADR 0484).
+package buildrun

modules/mesh-delivery-builder/buildrun/go.mod

@@ -0,0 +1,22 @@
+module git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun
+
+go 1.26.0
+
+require (
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128
+	github.com/nats-io/nats.go v1.54.0
+)
+
+require (
+	github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op // indirect
+	github.com/google/go-tpm v0.9.8 // indirect
+	github.com/klauspost/compress v1.20.0 // indirect
+	github.com/minio/highwayhash v1.0.4 // indirect
+	github.com/nats-io/jwt/v2 v2.8.1 // indirect
+	github.com/nats-io/nats-server/v2 v2.11.17 // indirect
+	github.com/nats-io/nkeys v0.4.16 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
+	golang.org/x/crypto v0.57.0 // indirect
+	golang.org/x/sys v0.48.0 // indirect
+	golang.org/x/time v0.15.0 // indirect
+)

modules/mesh-delivery-builder/buildrun/go.sum

@@ -0,0 +1,27 @@
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128 h1:aI1DhZAuqVBXbybSqhLNOGX5rUOrn9T0cHNCDUQF7IQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
+github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
+github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=
+github.com/google/go-tpm v0.9.8/go.mod h1:h9jEsEECg7gtLis0upRBQU+GhYVH6jMjrFxI8u6bVUY=
+github.com/klauspost/compress v1.20.0 h1:a3C1ke2ohxFymNlb2HWAHjDeKCI90scRskErZkR0ezA=
+github.com/klauspost/compress v1.20.0/go.mod h1:LUdAzn7YLVvxLpc7y3V1m40wESHTgc1422pwwBSKYuI=
+github.com/minio/highwayhash v1.0.4 h1:asJizugGgchQod2ja9NJlGOWq4s7KsAWr5XUc9Clgl4=
+github.com/minio/highwayhash v1.0.4/go.mod h1:GGYsuwP/fPD6Y9hMiXuapVvlIUEhFhMTh0rxU3ik1LQ=
+github.com/nats-io/jwt/v2 v2.8.1 h1:V0xpGuD/N8Mi+fQNDynXohVvp7ZztevW5io8CUWlPmU=
+github.com/nats-io/jwt/v2 v2.8.1/go.mod h1:nWnOEEiVMiKHQpnAy4eXlizVEtSfzacZ1Q43LIRavZg=
+github.com/nats-io/nats-server/v2 v2.11.17 h1:GKEghcFK6A+aFx11Yf1LjgLC3txAwvyhnYzhBIQZA8I=
+github.com/nats-io/nats-server/v2 v2.11.17/go.mod h1:B1sFVz4StNosQ903ak4N1G01Fl/9f8e06mXpFIE2K24=
+github.com/nats-io/nats.go v1.54.0 h1:vsXoOxjHp/GmPUN+EcI7uOf/uB+iAP+kEsAFNQN0yzA=
+github.com/nats-io/nats.go v1.54.0/go.mod h1:y+DZoD1oBOYfZTU681eTUiUjI0vbqYGixNVFHcjHJ0k=
+github.com/nats-io/nkeys v0.4.16 h1:rd5oAuLOb8mnAycB0xleuEBNS1pVVnN0fv/FF34Eypg=
+github.com/nats-io/nkeys v0.4.16/go.mod h1:llLgWoI0o4z/Q57q2R1kHfmocyhGV6VG/U18Glg1Afs=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+golang.org/x/crypto v0.57.0 h1:3ZVCjf8Ggz7zneR/EHRVx68Ctf+2pmIMP2UFhh9cC6M=
+golang.org/x/crypto v0.57.0/go.mod h1:Fdz0i5U6CoizGwLda9DttjSk6qlZo25zYNtR+ycvuZA=
+golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
+golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
+golang.org/x/time v0.15.0 h1:bbrp8t3bGUeFOx08pvsMYRTCVSMk89u4tKbNOZbp88U=
+golang.org/x/time v0.15.0/go.mod h1:Y4YMaQmXwGQZoFaVFk4YpCt4FLQMYKZe9oeV/f4MSno=

modules/mesh-delivery-builder/buildrun/have.go

@@ -0,0 +1,56 @@
+package buildrun
+
+import (
+	"sync"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// HaveSet holds what each node's node-engine says of each module on it (node-engine_have, key `<node>.<module>`): the
+// builder reads it to know whether a node's build module is running and healthy, since a build module whose installed
+// toolchain is not the one its recipe builds with is unhealthy (mesh-build-go build_go_health) and its steps would
+// refuse (ADR 0478 clause 3). A module the node-engine has written no key of is not healthy. Safe for use from the watch
+// and from a build at once.
+type HaveSet struct {
+	mu      sync.Mutex
+	healthy map[string]bool // by `<node>.<module>`
+}
+
+// Put takes a change of the have bucket in and answers whether a module's healthy state changed. A node's own key
+// (`<node>.node`) and a value that is not a have are left out.
+func (s *HaveSet) Put(key string, value []byte, deleted bool) bool {
+	node, module, isNode, err := delivery.ParseHaveKey(key)
+	if err != nil || isNode {
+		return false
+	}
+	ok := false
+	if !deleted {
+		h, err := delivery.DecodeHave(value)
+		if err != nil {
+			return false
+		}
+		ok = h.Phase == delivery.PhaseRunning && h.Health == delivery.HealthOK
+	}
+	k := node + "." + module
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.healthy[k] == ok {
+		return false
+	}
+	if s.healthy == nil {
+		s.healthy = map[string]bool{}
+	}
+	if ok {
+		s.healthy[k] = true
+	} else {
+		delete(s.healthy, k)
+	}
+	return true
+}
+
+// Healthy is whether the module on the node was last seen running and healthy.
+func (s *HaveSet) Healthy(node, module string) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.healthy[node+"."+module]
+}

modules/mesh-delivery-builder/buildrun/heardends.go

@@ -0,0 +1,236 @@
+package buildrun
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **A step's end is never only its own watch's to hear** (the lost check of 2026-10-28: mesh-catalog #553's verdict
+// stayed running after its step mvsgthyjed5786 had passed on shanks at 19:09:31Z; the watch of that one key, opened at
+// 18:46:05Z, heard neither the step's start nor its end and never closed, while a watch opened at 18:58:48Z heard its own
+// step end). HeardEnds stands between the asker (Asker) and the watch of each ask's step key: when it is
+// nudged, every ask it waits on reads its step keys now (a read, not the watch) and hands what it reads to its wait, so a
+// step that ended is judged even when its own watch went deaf. A watch that closes under a wait is opened again, at most
+// reopenTries times. It is nudged on an event (Nudge): any step of the same build module ending (one watch of each steps
+// state, HearEnds), a reconnect to the bus, and whatever else the asker hears (the checker: checker_ask_again).
+// It holds no timer. Every asker of the build seats waits through it (the checker and the builder, HearEnds).
+
+// StepReader reads, now, every step a build module's steps state holds for an ask: its keys `*.<ask id>`.
+type StepReader interface {
+	AskSteps(ctx context.Context, module, askID string) ([]delivery.Step, error)
+}
+
+// reopenTries is how often a wait opens its ask's watch again after it closed, before the wait ends failed.
+const reopenTries = 3
+
+// HeardEnds is an AskWaiter over Inner that also reads an ask's steps when nudged. Safe for concurrent use.
+type HeardEnds struct {
+	Inner AskWaiter
+	Read  StepReader
+	Logf  func(format string, args ...any)
+
+	mu      sync.Mutex
+	waiting map[string]*waitedAsk // by ask id
+}
+
+type waitedAsk struct {
+	module string
+	nudge  chan struct{}
+}
+
+func (h *HeardEnds) logf(format string, args ...any) {
+	if h.Logf != nil {
+		h.Logf(format, args...)
+	}
+}
+
+// WatchAsk is AskWaiter's: what Inner's watch hands, and, at each nudge, what the ask's keys hold now.
+func (h *HeardEnds) WatchAsk(ctx context.Context, module, askID string) (<-chan delivery.Step, error) {
+	in, err := h.Inner.WatchAsk(ctx, module, askID)
+	if err != nil {
+		return nil, err
+	}
+	w := &waitedAsk{module: module, nudge: make(chan struct{}, 1)}
+	h.mu.Lock()
+	if h.waiting == nil {
+		h.waiting = map[string]*waitedAsk{}
+	}
+	h.waiting[askID] = w
+	h.mu.Unlock()
+	out := make(chan delivery.Step)
+	go func() {
+		defer close(out)
+		defer func() {
+			h.mu.Lock()
+			if h.waiting[askID] == w {
+				delete(h.waiting, askID)
+			}
+			h.mu.Unlock()
+		}()
+		send := func(s delivery.Step) bool {
+			select {
+			case out <- s:
+				return true
+			case <-ctx.Done():
+				return false
+			}
+		}
+		reopened := 0
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case s, ok := <-in:
+				if !ok {
+					if ctx.Err() != nil || reopened >= reopenTries {
+						h.logf("the watch of the ask %s's step on %s closed %d times; its wait ends", askID, module, reopened+1)
+						return
+					}
+					reopened++
+					if in, err = h.Inner.WatchAsk(ctx, module, askID); err != nil {
+						h.logf("the watch of the ask %s's step on %s closed and cannot be opened again, so its wait ends: %v", askID, module, err)
+						return
+					}
+					h.logf("the watch of the ask %s's step on %s closed; opened again (%d of %d)", askID, module, reopened, reopenTries)
+					continue
+				}
+				if !send(s) {
+					return
+				}
+			case <-w.nudge:
+				if h.Read == nil {
+					continue
+				}
+				steps, err := h.Read.AskSteps(ctx, module, askID)
+				if err != nil {
+					h.logf("the steps of the ask %s on %s cannot be read: %v", askID, module, err)
+					continue
+				}
+				for _, s := range steps {
+					if s.State != delivery.StepRunning {
+						h.logf("the ask %s's step on %s ended %s, read at a nudge: its watch had not handed it over", askID, s.Node, s.State)
+					}
+					if !send(s) {
+						return
+					}
+				}
+			}
+		}
+	}()
+	return out, nil
+}
+
+// Nudge has every ask waited on of module read its steps now; module "" nudges every ask.
+func (h *HeardEnds) Nudge(module string) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	for _, w := range h.waiting {
+		if module == "" || w.module == module {
+			select {
+			case w.nudge <- struct{}{}:
+			default: // a nudge is pending already
+			}
+		}
+	}
+}
+
+// Waiting is how many asks are waited on now.
+func (h *HeardEnds) Waiting() int {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return len(h.waiting)
+}
+
+// AskSteps is StepReader's: the keys `*.<ask id>` of the build module's steps state, read now.
+func (s JetStreamAsks) AskSteps(ctx context.Context, module, askID string) ([]delivery.Step, error) {
+	pattern, err := delivery.AskStepWatch(askID)
+	if err != nil {
+		return nil, err
+	}
+	kv, err := s.JS.KeyValue(ctx, delivery.StepsBucket(module))
+	if err != nil {
+		return nil, fmt.Errorf("the bucket %s: %w", delivery.StepsBucket(module), err)
+	}
+	lister, err := kv.ListKeysFiltered(ctx, pattern)
+	if err != nil {
+		return nil, err
+	}
+	var out []delivery.Step
+	for key := range lister.Keys() {
+		e, err := kv.Get(ctx, key)
+		if err != nil {
+			continue // deleted between the list and the read
+		}
+		if step, err := delivery.DecodeStep(e.Value()); err == nil {
+			out = append(out, step)
+		}
+	}
+	return out, nil
+}
+
+// HearEnds is the HeardEnds every asker of the build seats waits through: over inner (the asks' own watches, or a
+// LostAskWaiter's inner), reading with asks, and nudged at each step end of each of modules (one watch of each steps state,
+// updates only; one that closes is opened again, and said and left after reopenTries closes in a row that heard nothing). The asker nudges it at a reconnect too (Nudge("")).
+func HearEnds(ctx context.Context, asks JetStreamAsks, inner AskWaiter, modules []string, logf func(string, ...any)) *HeardEnds {
+	if logf == nil {
+		logf = func(string, ...any) {}
+	}
+	h := &HeardEnds{Inner: inner, Read: asks, Logf: logf}
+	for _, module := range modules {
+		kv, err := asks.JS.KeyValue(ctx, delivery.StepsBucket(module))
+		if err != nil {
+			logf("the steps of %s cannot be read (%v): an ask whose own watch goes deaf is read only at a reconnect", module, err)
+			continue
+		}
+		go h.follow(ctx, kv, module)
+	}
+	return h
+}
+
+func (h *HeardEnds) follow(ctx context.Context, kv jetstream.KeyValue, module string) {
+	silent := 0 // closes in a row having heard nothing
+	for ctx.Err() == nil {
+		w, err := kv.WatchAll(ctx, jetstream.UpdatesOnly())
+		if err != nil {
+			h.logf("the steps of %s cannot be watched, so an ask whose own watch goes deaf is read only at a reconnect: %v", module, err)
+			return
+		}
+		heard := false
+		for e := range w.Updates() {
+			if e == nil || e.Operation() != jetstream.KeyValuePut {
+				continue
+			}
+			heard = true
+			if step, err := delivery.DecodeStep(e.Value()); err == nil && step.State != delivery.StepRunning {
+				h.Nudge(module)
+			}
+		}
+		_ = w.Stop()
+		if ctx.Err() != nil {
+			return
+		}
+		h.Nudge(module) // a step may have ended while the watch was closing
+		if heard {
+			silent = 0
+		} else if silent++; silent >= reopenTries {
+			h.logf("the watch of the steps of %s closed %d times in a row having heard nothing, so it is left: an ask whose own watch goes deaf is read only at a reconnect", module, silent)
+			return
+		}
+		h.logf("the watch of the steps of %s closed; opened again", module)
+	}
+}
+
+// AskSteps is StepReader's: the last step written for the ask, if any.
+func (f *FakeAsks) AskSteps(_ context.Context, _ string, askID string) ([]delivery.Step, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if s := f.steps[askID]; len(s) > 0 {
+		return []delivery.Step{s[len(s)-1]}, nil
+	}
+	return nil, nil
+}

modules/mesh-delivery-builder/buildrun/lostask.go

@@ -0,0 +1,503 @@
+package buildrun
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/health"
+	"git.novox.be/novox/mesh-sdk/go/process"
+)
+
+// **An ask the build seat gave up on ends its step** (novox/hq issue 734). A build seat's worker offers an ask
+// delivery.AskMaxDeliver times; one handed out that often without an answer (a bus reload that drops every hand-out, a node
+// that dies taking it each time) is given up by the server, and the controller keeps a copy of it in DEAD_LETTERS under
+// mesh.events.dead.<seat stream>.<worker>, with the ask's message id (its ask id), how often it was handed out and when it
+// was given up. No build node writes a step for it, so an asker that waits for the step waits for ever: a try stays
+// running and holds a try place, a check's verdict stays running and its pull request waits.
+//
+// An asker of the build seats (the checker, the builder) hears those copies (DeadLetterHearing: an ordered consumer on
+// DEAD_LETTERS filtered to the build seats' streams, granted to a user of a seat pulled by kind, buscompose
+// DeadLetterReads) into DeadLetters, and LostAskWaiter ends the waiting step at once as failed on the node LostNode, its
+// reason saying LostWords; the asker decides what follows (the checker ends a try as error and asks a check again, the
+// builder asks its part of a build again).
+//
+// Belt and braces, where the asker says so in the context (NotTakenBound; the checker's tries): an ask no build node took
+// within a bound ends the same way, saying NotTakenWords. An ask waits in the stream as long as the backlog is otherwise
+// (ADR 0525 §9): a backlog is no fault.
+
+// LostNode is the node a step ended for a lost ask names: no build node wrote it.
+const LostNode = "bus"
+
+// The words of a step ended for its ask.
+const (
+	LostWords     = "its ask was given up by the build seat"
+	NotTakenWords = "no build node took its ask"
+)
+
+// The headers the controller keeps a given-up message's copy with in DEAD_LETTERS (mesh-controller internal/link
+// deadletters.go): the original message id (an ask's is its ask id), how often it was handed out, when it was given up.
+const (
+	DeadHeaderMsgID      = "Mesh-Dead-Msg-Id"
+	DeadHeaderDeliveries = "Mesh-Dead-Deliveries"
+	DeadHeaderGaveUp     = "Mesh-Dead-Gave-Up"
+	DeadHeaderStream     = "Mesh-Dead-Stream"
+)
+
+// DeadLettersStream is the stream the controller keeps given-up messages in, and DeadLetterFilter the subjects of one seat
+// stream's copies there (buscompose DeadLetterSubject).
+const DeadLettersStream = "DEAD_LETTERS"
+
+// DeadLetterFilter is the subjects DEAD_LETTERS keeps a seat stream's given-up messages under.
+func DeadLetterFilter(stream string) string { return "mesh.events.dead." + stream + ".>" }
+
+// SeatStream is the stream of a build seat's language (buscompose seatStreamName of node-build-<language>).
+func SeatStream(language string) string { return "SEAT_NODE_BUILD_" + strings.ToUpper(language) }
+
+// GivenUp is one ask a build seat gave up on, as DEAD_LETTERS keeps it.
+type GivenUp struct {
+	AskID      string
+	Stream     string
+	Deliveries int
+	At         time.Time
+}
+
+// GivenUpOf reads a DEAD_LETTERS copy's headers; false when it names no message id.
+func GivenUpOf(header map[string][]string) (GivenUp, bool) {
+	get := func(k string) string {
+		if v := header[k]; len(v) > 0 {
+			return strings.TrimSpace(v[0])
+		}
+		return ""
+	}
+	g := GivenUp{AskID: get(DeadHeaderMsgID), Stream: get(DeadHeaderStream)}
+	if g.AskID == "" {
+		return GivenUp{}, false
+	}
+	g.Deliveries, _ = strconv.Atoi(get(DeadHeaderDeliveries))
+	g.At, _ = time.Parse(time.RFC3339Nano, get(DeadHeaderGaveUp))
+	return g, true
+}
+
+// Words are what a step ended for the given-up ask says.
+func (g GivenUp) Words() string {
+	at := "at an unknown time"
+	if !g.At.IsZero() {
+		at = "at " + g.At.UTC().Format(time.RFC3339)
+	}
+	return fmt.Sprintf("%s after %d deliveries %s (kept in %s); ask again", LostWords, g.Deliveries, at, DeadLettersStream)
+}
+
+// keptGivenUp is how many given-up asks DeadLetters remembers for a waiter that starts after the copy was heard.
+const keptGivenUp = 1024
+
+// DeadLetters holds the given-up asks heard, and hands each to the waiter of its ask. Safe for concurrent use.
+type DeadLetters struct {
+	mu       sync.Mutex
+	heard    map[string]GivenUp
+	order    []string
+	watchers map[string][]chan GivenUp
+}
+
+// Heard takes one given-up ask in.
+func (d *DeadLetters) Heard(g GivenUp) {
+	d.mu.Lock()
+	if d.heard == nil {
+		d.heard, d.watchers = map[string]GivenUp{}, map[string][]chan GivenUp{}
+	}
+	if _, ok := d.heard[g.AskID]; !ok {
+		d.order = append(d.order, g.AskID)
+		if len(d.order) > keptGivenUp {
+			delete(d.heard, d.order[0])
+			d.order = d.order[1:]
+		}
+	}
+	d.heard[g.AskID] = g
+	ws := d.watchers[g.AskID]
+	delete(d.watchers, g.AskID)
+	d.mu.Unlock()
+	for _, w := range ws {
+		w <- g // buffered, one each
+	}
+}
+
+// watch answers a channel that gets the ask's given-up copy once (at once when it was heard already), and its cancel.
+func (d *DeadLetters) watch(askID string) (<-chan GivenUp, func()) {
+	ch := make(chan GivenUp, 1)
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.heard == nil {
+		d.heard, d.watchers = map[string]GivenUp{}, map[string][]chan GivenUp{}
+	}
+	if g, ok := d.heard[askID]; ok {
+		ch <- g
+		return ch, func() {}
+	}
+	d.watchers[askID] = append(d.watchers[askID], ch)
+	return ch, func() {
+		d.mu.Lock()
+		defer d.mu.Unlock()
+		ws := d.watchers[askID]
+		for i, w := range ws {
+			if w == ch {
+				d.watchers[askID] = append(ws[:i], ws[i+1:]...)
+				break
+			}
+		}
+		if len(d.watchers[askID]) == 0 {
+			delete(d.watchers, askID)
+		}
+	}
+}
+
+type notTakenKey struct{}
+
+// NotTakenBound says, in ctx, that an ask no build node took within bound ends its step (a try's, never a check's).
+func NotTakenBound(ctx context.Context, bound time.Duration) context.Context {
+	return context.WithValue(ctx, notTakenKey{}, bound)
+}
+
+func notTakenBoundOf(ctx context.Context) time.Duration {
+	d, _ := ctx.Value(notTakenKey{}).(time.Duration)
+	return d
+}
+
+// LostAskWaiter is an AskWaiter that ends an ask's step when the build seat gave the ask up (DeadLetters), or, under
+// NotTakenBound, when no build node took it within the bound: it hands the asker a failed step whose reason says why, on
+// the node "bus". Every step the build module writes is handed on as it is.
+type LostAskWaiter struct {
+	Inner AskWaiter
+	Dead  *DeadLetters
+	// Hearing, when set, is asked to hear DEAD_LETTERS again each time an ask is waited for while it cannot: an ask put is
+	// the event that makes hearing matter.
+	Hearing interface {
+		Deaf() string
+		Again()
+	}
+	Now func() time.Time
+}
+
+func (w LostAskWaiter) now() time.Time {
+	if w.Now != nil {
+		return w.Now()
+	}
+	return time.Now()
+}
+
+// WatchAsk is AskWaiter's.
+func (w LostAskWaiter) WatchAsk(ctx context.Context, module, askID string) (<-chan delivery.Step, error) {
+	if w.Hearing != nil && w.Hearing.Deaf() != "" {
+		w.Hearing.Again()
+	}
+	inner, err := w.Inner.WatchAsk(ctx, module, askID)
+	if err != nil {
+		return nil, err
+	}
+	var dead <-chan GivenUp
+	cancel := func() {}
+	if w.Dead != nil {
+		dead, cancel = w.Dead.watch(askID)
+	}
+	// The not-taken bound is a context's (ADR 0437 §8: no timer), ended when a node takes the ask.
+	var notTaken <-chan struct{}
+	bound := notTakenBoundOf(ctx)
+	stopBound := func() {}
+	if bound > 0 {
+		var nt context.Context
+		nt, stopBound = context.WithTimeout(context.Background(), bound)
+		notTaken = nt.Done()
+	}
+	out := make(chan delivery.Step)
+	go func() {
+		defer close(out)
+		defer cancel()
+		defer func() { stopBound() }()
+		send := func(s delivery.Step) bool {
+			select {
+			case out <- s:
+				return true
+			case <-ctx.Done():
+				return false
+			}
+		}
+		ended := func(reason string) delivery.Step {
+			at := w.now().UTC()
+			return delivery.Step{ID: askID, Node: LostNode, State: delivery.StepFailed, Reason: reason, Ended: at}
+		}
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case s, ok := <-inner:
+				if !ok {
+					return
+				}
+				if notTaken != nil {
+					stopBound() // a node took it: its step is bounded by the asker from its start
+					notTaken = nil
+				}
+				if !send(s) {
+					return
+				}
+			case g := <-dead:
+				dead = nil
+				send(ended(g.Words()))
+				return
+			case <-notTaken:
+				send(ended(fmt.Sprintf("%s within %s of its put; it was lost or waits behind a backlog; ask again", NotTakenWords, bound)))
+				return
+			}
+		}
+	}()
+	return out, nil
+}
+
+// IsLost says whether a step was ended by LostAskWaiter because the build seat gave its ask up (LostWords).
+func IsLost(s delivery.Step) bool { return s.Node == LostNode && strings.Contains(s.Reason, LostWords) }
+
+// IsNotTaken says whether a step was ended by LostAskWaiter because no build node took its ask within the bound.
+func IsNotTaken(s delivery.Step) bool {
+	return s.Node == LostNode && strings.Contains(s.Reason, NotTakenWords)
+}
+
+// **The asker hears DEAD_LETTERS, tries again when it cannot, and says whether it hears** (issue 734). The read is
+// granted with the asker's seat traffic (buscompose DeadLetterReads); an asker started before its grant was composed is
+// refused, and an asker that only tried once would stay deaf until it starts again, silently. DeadLetterHearing tries in
+// the background, never holding the start up, and again on an event (Again): the asker's reconnect to the bus, and every
+// ask waited for while it is deaf (LostAskWaiter.Hearing); no timer. Each change of whether it hears is said (Said), so
+// the module's health tool says it: a deaf asker is not healthy.
+
+// Hearing is what a DeadLetterHearing says: whether it hears every build seat stream it follows, and why not.
+type Hearing struct {
+	Heard   bool      `json:"heard"`
+	Streams []string  `json:"streams"`
+	Why     string    `json:"why,omitempty"`
+	At      time.Time `json:"at"`
+}
+
+// HearingKey is the key a module keeps its Hearing under, in its own state (the checker's and the builder's hearing).
+const HearingKey = "dead-letters"
+
+// DeadLetterFollower starts following one seat stream's copies in DEAD_LETTERS from since, handing each given-up ask to
+// heard; it answers the stop, or why it cannot.
+type DeadLetterFollower interface {
+	Follow(ctx context.Context, stream string, since time.Time, heard func(GivenUp)) (func(), error)
+}
+
+// JetStreamDeadLetters is the bus side of a DeadLetterFollower: an ordered consumer on DEAD_LETTERS filtered to the
+// stream's copies, which resumes where it was after a reconnect and, reset before it heard any, starts at since again.
+type JetStreamDeadLetters struct{ JS jetstream.JetStream }
+
+// Follow is DeadLetterFollower's.
+func (j JetStreamDeadLetters) Follow(ctx context.Context, stream string, since time.Time, heard func(GivenUp)) (func(), error) {
+	cons, err := j.JS.OrderedConsumer(ctx, DeadLettersStream, jetstream.OrderedConsumerConfig{
+		FilterSubjects: []string{DeadLetterFilter(stream)}, DeliverPolicy: jetstream.DeliverByStartTimePolicy, OptStartTime: &since})
+	if err != nil {
+		return nil, err
+	}
+	cc, err := cons.Consume(func(m jetstream.Msg) {
+		if g, ok := GivenUpOf(m.Headers()); ok {
+			heard(g)
+		}
+	})
+	if err != nil {
+		return nil, err
+	}
+	return cc.Stop, nil
+}
+
+// DeadLetterHearing follows the build seats' given-up asks into Dead. Make it with NewDeadLetterHearing.
+type DeadLetterHearing struct {
+	follower DeadLetterFollower
+	streams  []string
+	dead     *DeadLetters
+	logf     func(string, ...any)
+	said     func(Hearing)
+	ctx      context.Context
+	since    time.Time
+
+	mu     sync.Mutex
+	stops  map[string]func()
+	why    map[string]string
+	trying bool
+	again  bool
+	told   *Hearing
+	wg     sync.WaitGroup
+}
+
+// NewDeadLetterHearing starts hearing the given-up asks of each language's build seat stream, in the background. said
+// is told each change of whether it hears (nil tells nothing); ctx ends it.
+func NewDeadLetterHearing(ctx context.Context, follower DeadLetterFollower, languages []string, dead *DeadLetters,
+	logf func(string, ...any), said func(Hearing)) *DeadLetterHearing {
+	h := &DeadLetterHearing{follower: follower, dead: dead, logf: logf, said: said, ctx: ctx, since: time.Now(),
+		stops: map[string]func(){}, why: map[string]string{}}
+	for _, l := range languages {
+		s := SeatStream(l)
+		h.streams = append(h.streams, s)
+		h.why[s] = "not tried yet"
+	}
+	if h.logf == nil {
+		h.logf = func(string, ...any) {}
+	}
+	h.Again()
+	return h
+}
+
+// Deaf says why a stream is not heard, or "" when every one is.
+func (h *DeadLetterHearing) Deaf() string {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return h.deafLocked()
+}
+
+func (h *DeadLetterHearing) deafLocked() string {
+	var out []string
+	for _, s := range h.streams {
+		if why, deaf := h.why[s]; deaf {
+			out = append(out, s+": "+why)
+		}
+	}
+	if len(out) == 0 {
+		return ""
+	}
+	return DeadLettersStream + " is not heard, so an ask a build seat gives up on is waited for until its bound: " +
+		strings.Join(out, "; ")
+}
+
+// Again tries, in the background, every stream not heard yet; a call while it tries makes it try once more after.
+func (h *DeadLetterHearing) Again() {
+	h.mu.Lock()
+	if h.trying {
+		h.again = true
+		h.mu.Unlock()
+		return
+	}
+	h.trying = true
+	h.mu.Unlock()
+	h.wg.Add(1)
+	go func() {
+		defer h.wg.Done()
+		for {
+			h.try()
+			h.mu.Lock()
+			if !h.again || h.ctx.Err() != nil {
+				h.trying = false
+				h.mu.Unlock()
+				return
+			}
+			h.again = false
+			h.mu.Unlock()
+		}
+	}()
+}
+
+// Wait returns when no try runs.
+func (h *DeadLetterHearing) Wait() { h.wg.Wait() }
+
+// Stop ends every stream's following.
+func (h *DeadLetterHearing) Stop() {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	for s, stop := range h.stops {
+		stop()
+		delete(h.stops, s)
+	}
+}
+
+func (h *DeadLetterHearing) try() {
+	for _, s := range h.streams {
+		h.mu.Lock()
+		_, deaf := h.why[s]
+		h.mu.Unlock()
+		if !deaf || h.ctx.Err() != nil {
+			continue
+		}
+		stream := s
+		stop, err := h.follower.Follow(h.ctx, stream, h.since, func(g GivenUp) {
+			h.logf("the ask %s on %s was given up after %d deliveries at %s: the wait for its step ends", g.AskID, g.Stream,
+				g.Deliveries, g.At.Format(time.RFC3339))
+			h.dead.Heard(g)
+		})
+		h.mu.Lock()
+		if err != nil {
+			h.why[stream] = err.Error()
+			h.logf("the asks %s gives up on are not heard (%s of %s); tried again at the next reconnect or ask: %v",
+				stream, DeadLetterFilter(stream), DeadLettersStream, err)
+		} else {
+			delete(h.why, stream)
+			h.stops[stream] = stop
+			h.logf("the asks %s gives up on are heard from %s", stream, DeadLettersStream)
+		}
+		h.mu.Unlock()
+	}
+	h.tell()
+}
+
+// tell says the hearing when it changed.
+func (h *DeadLetterHearing) tell() {
+	h.mu.Lock()
+	why := h.deafLocked()
+	now := Hearing{Heard: why == "", Streams: append([]string(nil), h.streams...), Why: why, At: time.Now().UTC()}
+	same := h.told != nil && h.told.Heard == now.Heard && h.told.Why == now.Why
+	if !same {
+		h.told = &now
+	}
+	h.mu.Unlock()
+	if !same && h.said != nil {
+		h.said(now)
+	}
+}
+
+// HearingState is the name of the state an asker keeps its Hearing in (`<module>_hearing`, key HearingKey), which its
+// health tool reads.
+const HearingState = "hearing"
+
+// HearingKeeper is where a Hearing is kept: a jetstream.KeyValue, or a process.AwaitedBucket for a state that may not be
+// on the bus at the part's start (issue 1790), which keeps the latest until it appears and answers process.ErrNotYet.
+type HearingKeeper interface {
+	Put(ctx context.Context, key string, value []byte) (uint64, error)
+}
+
+// SayHearing is a DeadLetterHearing's said that keeps each Hearing in kv under HearingKey; nil kv keeps nothing and
+// says so once. A write kv keeps for later (process.ErrNotYet) is not an error: the awaited bucket said it waits.
+func SayHearing(ctx context.Context, kv HearingKeeper, logf func(string, ...any)) func(Hearing) {
+	if kv == nil {
+		if logf != nil {
+			logf("whether %s is heard is not kept: the state %s is not there, so the health tool cannot say it", DeadLettersStream, HearingState)
+		}
+		return nil
+	}
+	return func(h Hearing) {
+		data, err := json.Marshal(h)
+		if err == nil {
+			_, err = kv.Put(ctx, HearingKey, data)
+		}
+		if err != nil && !errors.Is(err, process.ErrNotYet) && logf != nil {
+			logf("whether %s is heard could not be kept: %v", DeadLettersStream, err)
+		}
+	}
+}
+
+// HearingHealth is the health answer of an asker's kept Hearing (raw, empty when none is kept): healthy while it hears
+// DEAD_LETTERS, unhealthy saying why while it does not or has not said.
+func HearingHealth(raw []byte) health.Answer {
+	if len(raw) == 0 {
+		return health.Unhealthy("it has not said whether it hears " + DeadLettersStream + " (issue 734): it is starting, or its state " + HearingState + " is not there")
+	}
+	var h Hearing
+	if err := json.Unmarshal(raw, &h); err != nil {
+		return health.Unhealthy("what it keeps of hearing " + DeadLettersStream + " is not a hearing: " + err.Error())
+	}
+	if !h.Heard {
+		return health.Unhealthy(h.Why + " (since " + h.At.Format(time.RFC3339) + "; tried again at its next reconnect or ask)")
+	}
+	return health.Healthy("it hears " + DeadLettersStream + " for " + strings.Join(h.Streams, ", "))
+}

modules/mesh-delivery-builder/buildrun/modules.go

@@ -0,0 +1,7 @@
+package buildrun
+
+// The build modules the mesh runs, by the language each builds (ADR 0469).
+const (
+	GoBuildModule   = "mesh-build-go"
+	NodeBuildModule = "mesh-build-node"
+)

modules/mesh-delivery-builder/buildrun/places.go

@@ -0,0 +1,145 @@
+package buildrun
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"sync"
+)
+
+// DefaultCapacity is the build capacity of a node that has no setting: one build step at a time.
+const DefaultCapacity = 1
+
+// Places counts the build steps a part runs on each node and holds a lane back while its node is at its
+// capacity (the operator's decision of 2026-10-21; ADR 0478 clause 3). A lane is the fetch and the builds of one build
+// module on one node, run one step at a time, so a lane holds one place while it runs. A node is chosen for a lane by
+// reserving a place on it at the moment of the choice (ChooseNodes), so that builds choosing at once see each other's
+// choices and none waits on a full node while another has room. A lane waits for its place by watching the ends of the
+// other lanes, not by a timer: ending a lane wakes the waiting ones.
+type Places struct {
+	// Capacity is the number of steps at once by node; a node not in it has DefaultCapacity.
+	Capacity map[string]int
+
+	mu       sync.Mutex
+	running  map[string]int // lanes holding a place
+	reserved map[string]int // lanes chosen for the node that do not hold a place yet
+	changed  chan struct{}  // closed, and replaced, each time a lane ends
+}
+
+// CapacityOf is how many steps the part runs on the node at once: DefaultCapacity for a node the setting does not
+// name, and 0 for one it names so, where the part never builds.
+func (p *Places) CapacityOf(node string) int {
+	if n, ok := p.Capacity[node]; ok && n >= 0 {
+		return n
+	}
+	return DefaultCapacity
+}
+
+// Running is the steps in flight now, by node.
+func (p *Places) Running() map[string]int {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	out := make(map[string]int, len(p.running))
+	for n, c := range p.running {
+		if c > 0 {
+			out[n] = c
+		}
+	}
+	return out
+}
+
+// Reserved is the lanes chosen for a node that hold no place yet, by node.
+func (p *Places) Reserved() map[string]int {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	out := make(map[string]int, len(p.reserved))
+	for n, c := range p.reserved {
+		if c > 0 {
+			out[n] = c
+		}
+	}
+	return out
+}
+
+func (p *Places) init() {
+	if p.running == nil {
+		p.running = map[string]int{}
+	}
+	if p.reserved == nil {
+		p.reserved = map[string]int{}
+	}
+	if p.changed == nil {
+		p.changed = make(chan struct{})
+	}
+}
+
+// Acquire takes a place on the node, waiting while the node is at its capacity, and answers the function that gives it
+// back. A place reserved for the node by a choice is the one taken. It returns an error when ctx ends first, and then
+// gives up the reservation too.
+func (p *Places) Acquire(ctx context.Context, node string) (release func(), err error) {
+	for {
+		p.mu.Lock()
+		p.init()
+		if p.running[node] < p.CapacityOf(node) {
+			p.running[node]++
+			if p.reserved[node] > 0 {
+				p.reserved[node]--
+			}
+			p.mu.Unlock()
+			var once sync.Once
+			return func() {
+				once.Do(func() {
+					p.mu.Lock()
+					p.running[node]--
+					close(p.changed)
+					p.changed = make(chan struct{})
+					p.mu.Unlock()
+				})
+			}, nil
+		}
+		wait := p.changed
+		p.mu.Unlock()
+		select {
+		case <-wait:
+		case <-ctx.Done():
+			p.Cancel(node)
+			return nil, fmt.Errorf("waiting for a place on %s: %w", node, ctx.Err())
+		}
+	}
+}
+
+// Cancel gives up a place reserved for the node that will not be taken.
+func (p *Places) Cancel(node string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.init()
+	if p.reserved[node] > 0 {
+		p.reserved[node]--
+	}
+}
+
+// choose orders the nodes (those with room first, counting the lanes running and the lanes reserved, then the fewest of
+// them, then by name), keeps the first want and reserves a place on each, all at once.
+func (p *Places) choose(nodes []string, want int) []string {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.init()
+	load := func(n string) int { return p.running[n] + p.reserved[n] }
+	sort.SliceStable(nodes, func(i, j int) bool {
+		ri, rj := load(nodes[i]) < p.CapacityOf(nodes[i]), load(nodes[j]) < p.CapacityOf(nodes[j])
+		if ri != rj {
+			return ri
+		}
+		if load(nodes[i]) != load(nodes[j]) {
+			return load(nodes[i]) < load(nodes[j])
+		}
+		return nodes[i] < nodes[j]
+	})
+	if len(nodes) > want {
+		nodes = nodes[:want]
+	}
+	for _, n := range nodes {
+		p.reserved[n]++
+	}
+	return nodes
+}

modules/mesh-delivery-builder/buildrun/places_test.go

@@ -0,0 +1,104 @@
+package buildrun
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+)
+
+func acquireAsync(p *Places, node string) chan func() {
+	got := make(chan func(), 1)
+	go func() {
+		release, err := p.Acquire(context.Background(), node)
+		if err != nil {
+			close(got)
+			return
+		}
+		got <- release
+	}()
+	return got
+}
+
+func TestThreeStepsOnANodeOfCapacityTwoRunTwoAtOnceAndTheThirdStartsWhenOneEnds(t *testing.T) { // round 3
+	p := &Places{Capacity: map[string]int{"ace": 2}}
+	a, b := acquireAsync(p, "ace"), acquireAsync(p, "ace")
+	ra, rb := <-a, <-b
+	third := acquireAsync(p, "ace")
+	select {
+	case <-third:
+		t.Fatal("a third step started on a node of capacity 2 with two running")
+	case <-time.After(10 * time.Millisecond):
+	}
+	if p.Running()["ace"] != 2 {
+		t.Errorf("running = %v, want 2 on ace", p.Running())
+	}
+	ra()
+	select {
+	case r := <-third:
+		r()
+	case <-time.After(2 * time.Second):
+		t.Fatal("the third step did not start when one ended")
+	}
+	rb()
+}
+
+func TestANodeWithNoSettingRunsOneStepAtATime(t *testing.T) { // round 3
+	p := &Places{Capacity: map[string]int{"shanks": 3}}
+	first := <-acquireAsync(p, "g14")
+	second := acquireAsync(p, "g14")
+	select {
+	case <-second:
+		t.Fatal("two steps on a node without a setting")
+	case <-time.After(10 * time.Millisecond):
+	}
+	first()
+	r := <-second
+	r()
+	if p.CapacityOf("g14") != 1 || p.CapacityOf("shanks") != 3 {
+		t.Errorf("capacities = %d, %d", p.CapacityOf("g14"), p.CapacityOf("shanks"))
+	}
+}
+
+func TestAWaitingStepStopsWhenItsContextEnds(t *testing.T) { // round 3
+	p := &Places{}
+	r := <-acquireAsync(p, "ace")
+	defer r()
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() { _, err := p.Acquire(ctx, "ace"); done <- err }()
+	cancel()
+	select {
+	case err := <-done:
+		if err == nil {
+			t.Error("Acquire returned no error for a cancelled wait")
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("a cancelled wait did not return")
+	}
+}
+
+// The operator's decision of 2026-10-21 13:40: the builder builds on shanks and ace only; a capacity of 0 keeps it off a node.
+func TestACapacityOfZeroKeepsThePartOffTheNodeAndANodeNotNamedKeepsOne(t *testing.T) { // issue 1661
+	p := &Places{Capacity: map[string]int{"shanks": 3, "ace": 2, "g14": 0, "novox": 0}}
+	if p.CapacityOf("g14") != 0 || p.CapacityOf("novox") != 0 || p.CapacityOf("ace") != 2 || p.CapacityOf("other") != DefaultCapacity {
+		t.Errorf("capacities = %d %d %d %d, want 0 0 2 and the default for a node not named", p.CapacityOf("g14"), p.CapacityOf("novox"), p.CapacityOf("ace"), p.CapacityOf("other"))
+	}
+	entries := tcs("go", "go1.27.1", "ace", "g14", "novox", "shanks", "other")
+	for i := 0; i < 6; i++ {
+		nodes, _, err := ChooseNodes("go", entries, p, nil, 2)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, n := range nodes {
+			if n == "g14" || n == "novox" {
+				t.Fatalf("choice %d: %v includes a node of capacity 0", i, nodes)
+			}
+		}
+	}
+	// Only nodes of capacity 0 report: nothing qualifies, and the build says why.
+	_, _, err := ChooseNodes("go", tcs("go", "go1.27.1", "g14", "novox"), p, nil, 2)
+	if err == nil || !strings.Contains(err.Error(), "capacity") {
+		t.Errorf("only capacity-0 nodes: error = %v, want it to name the capacity", err)
+	}
+}

modules/mesh-delivery-builder/buildrun/presence.go

@@ -0,0 +1,53 @@
+package buildrun
+
+import (
+	"sync"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// PresenceSet holds which nodes are online, as the watchman writes it (mesh-delivery-watchman_presence, key `<node>`, the
+// node-engine's connection): a node asleep or off the bus is offline and its build module cannot answer. A node the
+// watchman has no key of is not online. Safe for use from the watch and from a build at once.
+type PresenceSet struct {
+	mu     sync.Mutex
+	online map[string]bool
+}
+
+// Put takes a change of the presence bucket in and answers whether a node's online state changed. A part's key and a
+// value that is not a presence are left out.
+func (s *PresenceSet) Put(key string, value []byte, deleted bool) bool {
+	node, part, _, err := delivery.ParsePresenceKey(key)
+	if err != nil || part != "" {
+		return false
+	}
+	on := false
+	if !deleted {
+		p, err := delivery.DecodePresence(value)
+		if err != nil {
+			return false
+		}
+		on = p.Online
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.online[node] == on {
+		return false
+	}
+	if s.online == nil {
+		s.online = map[string]bool{}
+	}
+	if on {
+		s.online[node] = true
+	} else {
+		delete(s.online, node)
+	}
+	return true
+}
+
+// Online is whether the watchman last saw the node online.
+func (s *PresenceSet) Online(node string) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.online[node]
+}

modules/mesh-delivery-builder/buildrun/presence_test.go

@@ -0,0 +1,43 @@
+package buildrun
+
+import (
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func presenceValue(t *testing.T, online bool) []byte {
+	t.Helper()
+	b, err := delivery.EncodePresence(delivery.Presence{Online: online})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return b
+}
+
+func TestPresenceSetKnowsOnlyNodesTheWatchmanSawOnline(t *testing.T) { // 1607 review 3
+	var s PresenceSet
+	if s.Online("ace") {
+		t.Error("a node the watchman never wrote is online")
+	}
+	if !s.Put("ace", presenceValue(t, true), false) || !s.Online("ace") {
+		t.Error("ace online was not taken in")
+	}
+	if s.Put("ace", presenceValue(t, true), false) {
+		t.Error("the same presence again counted as a change")
+	}
+	if !s.Put("ace", presenceValue(t, false), false) || s.Online("ace") {
+		t.Error("ace going offline was not taken in")
+	}
+	s.Put("g14", presenceValue(t, true), false)
+	if !s.Put("g14", nil, true) || s.Online("g14") {
+		t.Error("a deleted key is still online")
+	}
+	// A part's instance (part.<part>.<instance>) is not a node.
+	if s.Put("part.mesh-delivery-builder.novox", presenceValue(t, true), false) || s.Online("part") {
+		t.Error("a part's key was taken for a node")
+	}
+	if s.Put("novox", []byte("junk"), false) {
+		t.Error("junk counted")
+	}
+}

modules/mesh-delivery-builder/buildrun/standing.go

@@ -0,0 +1,225 @@
+package buildrun
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"maps"
+	"slices"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/process"
+)
+
+// A build module writes <node>.<language> of its toolchains state on every node it runs on, and nothing deletes the key
+// when the module leaves a node: no part writes another module's state, and the module is gone. A report of a node the
+// build module no longer runs on is therefore no builder's (issue 1940: mesh-build-node taken off ace on 2026-10-23 left
+// ace.typescript at v26.12.0, and every Node fingerprint said "builders disagree").
+//
+// ToolchainGate stands between the toolchains buckets and what takes their entries in (the indexer's PutToolchain, a
+// ToolchainSet): an entry is passed on only while the placement (the seat mesh-placement's state `placement`, held by
+// the assigner, delivery.PlacementBucket, read by delivery.Placed; ADR 0567, ADR 0549 §3) places its build module on
+// its node, and only once it was written since that placement; it is passed on as deleted otherwise, said once, and
+// passed on when its node writes it again. A report written before the placement is one an earlier run of the module
+// left (issue 1940, 2026-10-25 20:56: mesh-build-node put on ace again brought ace.typescript v26.12.0 of 2026-10-23
+// back into the agreement before the module ran there). Until the placement is settled, and while no node's placement
+// is held (before the assigner's adopt writes the first one, or where the state cannot be read), every entry is passed
+// on. Builders that run and report different versions still disagree: that refusal is the guard of novox/hq ADR 0465,
+// and it stays.
+//
+// This replaces the copies of the gate the indexer, the builder and the checker each kept over the controller's
+// assignments (issue 1940's subtask, issue 774: those go with the controller's lease, ADR 0549 §6).
+type ToolchainGate struct {
+	mu      sync.Mutex
+	modules map[string]bool                                           // the build modules whose toolchains pass the gate
+	forward func(module, key string, value []byte, deleted bool) bool // answers whether it changed what it holds
+	logf    func(format string, a ...any)
+	placed  *delivery.Placed
+	known   bool                         // the placement is settled
+	raw     map[string]map[string][]byte // module -> toolchains key -> value, as the bucket holds it
+	left    map[string]string            // <module>/<key> -> why it was said left out, so each reason is said once
+}
+
+// NewToolchainGate is a gate over the toolchains of modules, passing what stands on to forward and saying with logf what
+// it leaves out.
+func NewToolchainGate(modules []string, forward func(module, key string, value []byte, deleted bool) bool, logf func(string, ...any)) *ToolchainGate {
+	g := &ToolchainGate{modules: map[string]bool{}, forward: forward, logf: logf, placed: delivery.NewPlaced(),
+		raw: map[string]map[string][]byte{}, left: map[string]string{}}
+	for _, m := range modules {
+		g.modules[m] = true
+	}
+	return g
+}
+
+// Toolchain takes one change of a build module's toolchains bucket in and answers whether what it passed on changed.
+func (g *ToolchainGate) Toolchain(module, key string, value []byte, deleted bool) bool {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	if g.raw[module] == nil {
+		g.raw[module] = map[string][]byte{}
+	}
+	if deleted {
+		delete(g.raw[module], key)
+	} else {
+		g.raw[module][key] = value
+	}
+	return g.pass(module, key)
+}
+
+// Placement takes one revision of the seat mesh-placement's placement in (at is when the bus wrote it) and answers whether what it
+// passed on changed. A value that does not read is said, and places nothing on its node.
+func (g *ToolchainGate) Placement(key string, value []byte, deleted bool, at time.Time) bool {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	was := g.placed.Seeded()
+	node, changed, err := g.placed.Put(key, value, deleted, at)
+	if err != nil {
+		g.logf("%s: %v (issue 1940)", delivery.PlacementBucket, err)
+	}
+	if !g.known {
+		return false
+	}
+	if was != g.placed.Seeded() {
+		// The first placement came, or the last went: every report's standing changed.
+		return g.all()
+	}
+	return g.again(node, changed)
+}
+
+// Settled says the placement's history is read: from now on only the reports of placed nodes pass, once a node's
+// placement is held. It answers whether what it passed on changed.
+func (g *ToolchainGate) Settled() bool {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	g.known = true
+	return g.all()
+}
+
+// all passes on every report again. The caller holds mu.
+func (g *ToolchainGate) all() bool {
+	changed := false
+	for _, module := range slices.Sorted(maps.Keys(g.raw)) {
+		for _, k := range slices.Sorted(maps.Keys(g.raw[module])) {
+			changed = g.pass(module, k) || changed
+		}
+	}
+	return changed
+}
+
+// again passes on every report of node by a build module among modules. The caller holds mu.
+func (g *ToolchainGate) again(node string, modules []string) bool {
+	changed := false
+	for _, module := range modules {
+		if !g.modules[module] {
+			continue
+		}
+		for _, k := range slices.Sorted(maps.Keys(g.raw[module])) {
+			if n, _, err := delivery.ParseToolchainKey(k); err == nil && n == node {
+				changed = g.pass(module, k) || changed
+			}
+		}
+	}
+	return changed
+}
+
+// pass hands one key on as it stands: its value when its node is placed and wrote it since (or the placement is not
+// known), deleted otherwise. The caller holds mu.
+func (g *ToolchainGate) pass(module, key string) bool {
+	value, held := g.raw[module][key]
+	if !held {
+		return g.forward(module, key, nil, true)
+	}
+	node, _, err := delivery.ParseToolchainKey(key)
+	why := ""
+	if err == nil && g.known && g.placed.Seeded() {
+		why = g.leftOut(module, node, value)
+	}
+	if why == "" {
+		delete(g.left, module+"/"+key)
+		return g.forward(module, key, value, false)
+	}
+	if g.left[module+"/"+key] != why {
+		g.left[module+"/"+key] = why
+		g.logf("%s.%s is left out of the agreed toolchain: %s (issue 1940)", delivery.ToolchainsBucket(module), key, why)
+	}
+	return g.forward(module, key, nil, true)
+}
+
+// leftOut is why a node's report is no builder's, or empty when it counts: the catalogue does not place the module on its
+// node, or the report was written before it did. A value that is no toolchain is passed on for its reader to refuse.
+// The caller holds mu.
+func (g *ToolchainGate) leftOut(module, node string, value []byte) string {
+	since, placed := g.placed.Since(node, module)
+	if !placed {
+		return fmt.Sprintf("the catalogue does not place %s on %s, so it is no builder", module, node)
+	}
+	tc, err := delivery.DecodeToolchain(value)
+	if err == nil && tc.At.Before(since) {
+		return fmt.Sprintf("it was written at %s, before %s was placed on %s at %s: it counts once %s writes it again",
+			tc.At.UTC().Format(time.RFC3339), module, node, since.UTC().Format(time.RFC3339), node)
+	}
+	return ""
+}
+
+// FollowPlacement reads the seat mesh-placement's placement with its history into gate, says it settled, and follows it; changed
+// is told whenever what the gate passes on changed. Where the state cannot be read or watched (not there, or this part
+// may not read it) it says so and the gate passes every report on: not fatal, since an indexer, builder or checker that
+// stops for it stops every delivery (issue 1945). An error of the watch after that ends on the channel.
+func FollowPlacement(ctx context.Context, js process.BucketOpener, gate *ToolchainGate, changed func(context.Context), logf func(string, ...any)) (<-chan error, error) {
+	errs := make(chan error, 1)
+	kv, err := js.KeyValue(ctx, delivery.PlacementBucket)
+	if err != nil {
+		logf("the state %s cannot be read, so every node's toolchain report counts, a build node's the catalogue does not place too (issue 1940): %v", delivery.PlacementBucket, err)
+		return errs, nil
+	}
+	w, err := kv.WatchAll(ctx, jetstream.IncludeHistory())
+	if err != nil {
+		logf("the state %s cannot be watched, so every node's toolchain report counts, a build node's the catalogue does not place too (issue 1940): %v", delivery.PlacementBucket, err)
+		return errs, nil
+	}
+	put := func(e jetstream.KeyValueEntry) bool {
+		return gate.Placement(e.Key(), e.Value(), e.Operation() != jetstream.KeyValuePut, e.Created())
+	}
+	for settled := false; !settled; {
+		select {
+		case <-ctx.Done():
+			_ = w.Stop()
+			return errs, ctx.Err()
+		case e, ok := <-w.Updates():
+			if !ok {
+				return errs, errors.New("the watch of " + delivery.PlacementBucket + " ended before it settled")
+			}
+			if e == nil {
+				settled = true
+				continue
+			}
+			put(e)
+		}
+	}
+	if gate.Settled() {
+		changed(ctx)
+	}
+	go func() {
+		defer func() { _ = w.Stop() }()
+		for {
+			select {
+			case <-ctx.Done():
+				errs <- ctx.Err()
+				return
+			case e, ok := <-w.Updates():
+				if !ok {
+					errs <- errors.New("the watch of " + delivery.PlacementBucket + " ended")
+					return
+				}
+				if e != nil && put(e) {
+					changed(ctx)
+				}
+			}
+		}
+	}()
+	return errs, nil
+}

modules/mesh-delivery-builder/buildrun/standing_test.go

@@ -0,0 +1,263 @@
+package buildrun
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func gateReport(t *testing.T, node, version string, at time.Time) (string, []byte) {
+	t.Helper()
+	key, err := delivery.ToolchainKey(node, "typescript")
+	if err != nil {
+		t.Fatal(err)
+	}
+	value, err := delivery.EncodeToolchain(delivery.Toolchain{Language: "typescript", Version: version, Recipe: "f59571cf4be75adf", At: at})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return key, value
+}
+
+// placing is a value of the state `placement` placing modules on node.
+func placing(t *testing.T, node string, modules ...string) (string, []byte) {
+	t.Helper()
+	p := delivery.Placement{Node: node}
+	for _, m := range modules {
+		p.Modules = append(p.Modules, delivery.PlacedModule{Module: m})
+	}
+	values, err := delivery.PlacementValues(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	key, _ := delivery.PlacementNodeKey(node)
+	return key, values[key]
+}
+
+// placingLegacy is placing in the form before, `placement.<node>` (research 072 row 37).
+func placingLegacy(t *testing.T, node string, modules ...string) (string, []byte) {
+	t.Helper()
+	p := delivery.Placement{Node: node}
+	for _, m := range modules {
+		p.Modules = append(p.Modules, delivery.PlacedModule{Module: m})
+	}
+	key, _ := delivery.LegacyPlacementKey(node)
+	value, err := delivery.EncodePlacement(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return key, value
+}
+
+func agreedOf(set *ToolchainSet) (string, string) {
+	tc, none := delivery.AgreedToolchain(set.Entries("typescript"))
+	return tc.Version, none
+}
+
+// Issue 1940, the gate over the catalogue's placement (issue 774, ADR 0549 §3): a build node's report counts only while
+// the placement places its build module on its node, and only once written since; before the placement is settled, and
+// while no node's placement is held, every report counts. The live cases: mesh-build-node taken off ace left
+// ace.typescript at v26.12.0 against v26.12.1 on the three others; put on ace again, its report of 2026-10-23 06:29 came
+// back before the module ran there.
+func TestToolchainGate(t *testing.T) {
+	old := time.Date(2026, 10, 23, 6, 29, 18, 0, time.UTC)     // ace's report from its earlier run
+	placed := time.Date(2026, 10, 25, 19, 56, 45, 0, time.UTC) // mesh-build-node placed on ace again
+	three := []string{"g14", "novox", "shanks"}
+	start := func(t *testing.T, seeded bool) (*ToolchainGate, *ToolchainSet, *[]string) {
+		set := &ToolchainSet{}
+		said := &[]string{}
+		gate := NewToolchainGate([]string{GoBuildModule, NodeBuildModule}, set.Put, func(f string, a ...any) { *said = append(*said, fmt.Sprintf(f, a...)) })
+		for _, node := range three {
+			if seeded {
+				key, value := placing(t, node, NodeBuildModule)
+				gate.Placement(key, value, false, old.Add(-time.Hour))
+			}
+			key, value := gateReport(t, node, "v26.12.1", placed.Add(time.Minute))
+			gate.Toolchain(NodeBuildModule, key, value, false)
+		}
+		return gate, set, said
+	}
+
+	t.Run("not placed on ace: its report is no builder's", func(t *testing.T) {
+		gate, set, said := start(t, true)
+		key, value := gateReport(t, "ace", "v26.12.0", old)
+		gate.Toolchain(NodeBuildModule, key, value, false)
+		if a := delivery.ToolchainAgreement(set.Entries("typescript")); len(a.SittingOut) != 1 || a.SittingOut[0].Node != "ace" { // ADR 0584: the majority is agreed, ace's report counts as the one that sits out
+			t.Fatalf("before the placement is settled every report counts; got %+v", a)
+		}
+		k, v := placing(t, "ace", GoBuildModule) // another build module on ace: no matter
+		gate.Placement(k, v, false, old)
+		if !gate.Settled() {
+			t.Fatal("settling left ace's report out, so what was passed on changed")
+		}
+		if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+			t.Fatalf("the placed nodes agree on v26.12.1; got %q, %q", v, none)
+		}
+		if len(*said) != 1 || !strings.Contains((*said)[0], "does not place mesh-build-node on ace") {
+			t.Fatalf("ace's report is said left out once; said %q", *said)
+		}
+		if gate.Toolchain(NodeBuildModule, key, value, false) {
+			t.Fatal("a report of a node not placed changed what was passed on")
+		}
+		// Placed on ace with a report written since: it counts, and the builders really disagree.
+		k, v = placing(t, "ace", GoBuildModule, NodeBuildModule)
+		gate.Placement(k, v, false, old.Add(-time.Minute))
+		if a := delivery.ToolchainAgreement(set.Entries("typescript")); a.Toolchain.Version != "v26.12.1" || len(a.SittingOut) != 1 || a.SittingOut[0].Version != "v26.12.0" {
+			t.Fatalf("builders that run different versions: the majority is agreed and ace sits out; got %+v", a)
+		}
+		// Taken off ace again (its key deleted): its report goes again.
+		if !gate.Placement(k, nil, true, placed) {
+			t.Fatal("taking ace's placement away passed nothing on")
+		}
+		if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+			t.Fatalf("got %q, %q", v, none)
+		}
+		// A report deleted from the bucket goes whether its node is placed or not.
+		key, _ = gateReport(t, "g14", "v26.12.1", placed)
+		if !gate.Toolchain(NodeBuildModule, key, nil, true) || len(set.Entries("typescript")) != 2 {
+			t.Fatalf("deleting g14's report: %d entries left, want novox and shanks", len(set.Entries("typescript")))
+		}
+	})
+
+	for _, c := range []struct {
+		name   string
+		at     time.Time // when ace wrote its report
+		counts bool
+	}{
+		{"a report left before the placement", old, false},
+		{"a report written since the placement", placed.Add(30 * time.Second), true},
+	} {
+		t.Run(c.name, func(t *testing.T) {
+			gate, set, said := start(t, true)
+			k, v := placing(t, "ace") // ace's key, first heard placing nothing
+			gate.Placement(k, v, false, old.Add(-time.Hour))
+			gate.Settled()
+			k, v = placing(t, "ace", NodeBuildModule)
+			if gate.Placement(k, v, false, placed) {
+				t.Fatal("a placement with no report passed something on")
+			}
+			key, value := gateReport(t, "ace", "v26.12.0", c.at)
+			if got := gate.Toolchain(NodeBuildModule, key, value, false); got != c.counts {
+				t.Fatalf("ace's report passed on: %v, want %v", got, c.counts)
+			}
+			// ace's placement written again with another module beside: its standing does not move, nothing is said again.
+			k, v = placing(t, "ace", GoBuildModule, NodeBuildModule)
+			if gate.Placement(k, v, false, placed.Add(time.Minute)) {
+				t.Fatal("the same placement of mesh-build-node changed what was passed on")
+			}
+			if c.counts {
+				return
+			}
+			if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+				t.Fatalf("ace's left report is no builder's; got %q, %q", v, none)
+			}
+			if len(*said) != 1 || !strings.Contains((*said)[0], "before mesh-build-node was placed on ace at 2026-10-25T19:56:45Z") {
+				t.Fatalf("said %q, want once why ace's report is left out", *said)
+			}
+			key, value = gateReport(t, "ace", "v26.12.1", placed.Add(time.Minute))
+			if !gate.Toolchain(NodeBuildModule, key, value, false) || len(set.Entries("typescript")) != 4 {
+				t.Fatal("ace's new report was not passed on")
+			}
+		})
+	}
+
+	t.Run("no placement held: every report counts", func(t *testing.T) {
+		gate, set, _ := start(t, false)
+		key, value := gateReport(t, "ace", "v26.12.0", old)
+		gate.Toolchain(NodeBuildModule, key, value, false)
+		gate.Settled()
+		if n := len(set.Entries("typescript")); n != 4 {
+			t.Fatalf("before the first placement file every report counts; got %d", n)
+		}
+		k, v := placing(t, "g14", NodeBuildModule)
+		if !gate.Placement(k, v, false, old.Add(-time.Hour)) || len(set.Entries("typescript")) != 1 {
+			t.Fatalf("the first placement leaves every node it does not place out; got %d", len(set.Entries("typescript")))
+		}
+		if !gate.Placement(k, nil, true, placed) || len(set.Entries("typescript")) != 4 {
+			t.Fatal("the last placement gone: every report counts again")
+		}
+	})
+
+	t.Run("the history: a module in the first revision heard of a key stands since before it", func(t *testing.T) {
+		p := delivery.NewPlaced()
+		// ace in the form before, then converted: its module stands since before, the legacy key read no more.
+		k, v := placingLegacy(t, "ace", NodeBuildModule)
+		p.Put(k, v, false, old)
+		k, v = placing(t, "ace", NodeBuildModule)
+		if _, changed, err := p.Put(k, v, false, placed); len(changed) != 0 || err != nil {
+			t.Errorf("the conversion of ace's key changed %v, %v", changed, err)
+		}
+		if _, changed, _ := p.Put("ace."+NodeBuildModule, []byte("{}"), false, placed); len(changed) != 0 {
+			t.Errorf("a module key says which modules stand: %v", changed)
+		}
+		if k, v := placingLegacy(t, "ace"); true {
+			if _, changed, _ := p.Put(k, v, false, placed); len(changed) != 0 {
+				t.Errorf("the legacy key is read after the node key: %v", changed)
+			}
+		}
+		k2, v2 := placing(t, "g14")
+		p.Put(k2, v2, false, old)
+		k2, v2 = placing(t, "g14", NodeBuildModule)
+		if _, changed, _ := p.Put(k2, v2, false, placed); strings.Join(changed, ",") != NodeBuildModule {
+			t.Errorf("a module placed says changed %v", changed)
+		}
+		if _, _, err := p.Put("placement.novox", []byte("not json"), false, old); err == nil {
+			t.Error("a value that does not read was not said")
+		}
+		if s, ok := p.Since("ace", NodeBuildModule); !ok || !s.IsZero() {
+			t.Errorf("ace's module stands since %v, %v; want the zero time", s, ok)
+		}
+		if s, ok := p.Since("g14", NodeBuildModule); !ok || !s.Equal(placed) {
+			t.Errorf("g14's module stands since %v, %v; want the revision that placed it", s, ok)
+		}
+		if got := p.PlacedNodes(NodeBuildModule); strings.Join(got, ",") != "ace,g14" || len(p.ByNode()) != 2 || !p.Seeded() {
+			t.Errorf("PlacedNodes = %v, ByNode = %v", got, p.ByNode())
+		}
+	})
+
+	t.Run("a placement the bus refuses is said, and the part goes on", func(t *testing.T) {
+		var logs bytes.Buffer
+		logger := log.New(&logs, "", 0)
+		refused := errors.New("nats: permissions violation for publish to $JS.API.CONSUMER.CREATE.KV_mesh-delivery-assigner_placement")
+		gate, _, _ := start(t, false)
+		for _, bus := range []refusingBus{{err: refused}, {refuseOpen: true, err: refused}} {
+			if _, err := FollowPlacement(context.Background(), bus, gate, func(context.Context) {}, logger.Printf); err != nil {
+				t.Errorf("a refused placement stopped the start: %v", err)
+			}
+		}
+		if !strings.Contains(logs.String(), "cannot be watched") || !strings.Contains(logs.String(), "cannot be read") {
+			t.Errorf("the refusals were not said: %q", logs.String())
+		}
+	})
+}
+
+// refusingBus is a bus that refuses: every open (refuseOpen), or every watch of a bucket it opens, with err.
+type refusingBus struct {
+	refuseOpen bool
+	err        error
+}
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) {
+	if r.refuseOpen {
+		return nil, r.err
+	}
+	return refusedWatch{err: r.err}, nil
+}
+
+type refusedWatch struct {
+	jetstream.KeyValue
+	err error
+}
+
+func (r refusedWatch) WatchAll(context.Context, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
+}

modules/mesh-delivery-builder/buildrun/steps.go

@@ -0,0 +1,67 @@
+package buildrun
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// Caller calls a tool of a module on one named machine (mesh-sdk process.Conn.CallOn; ADR 0469 clause 3).
+type Caller interface {
+	CallOn(node, key string, body any) (json.RawMessage, error)
+}
+
+// Steps waits for the end of a build module's long step: the value of its key `<node>.<id>` in the module's steps state
+// (ADR 0469 clause 2) once its state is not running. It is a watch of that key, not a poll; it returns when the step
+// ends or ctx does.
+type Steps interface {
+	Wait(ctx context.Context, module, key string) (delivery.Step, error)
+}
+
+// Runner runs a build module's long steps: the call answers at once with the step's key, and the result is read from that
+// key when the step ends (ADR 0469 clause 2).
+type Runner struct {
+	Caller Caller
+	Steps  Steps
+	// Bound is how long a step may run before the builder stops waiting for it.
+	Bound time.Duration
+}
+
+// Run calls tool of the build module on node with args, waits for the step's end and answers its result. A step that
+// failed or was refused is an error naming the node, the state and the reason.
+func (r Runner) Run(ctx context.Context, module, node, tool string, args map[string]any) (json.RawMessage, error) {
+	raw, err := r.Caller.CallOn(node, module+"."+tool, args)
+	if err != nil {
+		return nil, fmt.Errorf("%s on %s: %w", tool, node, err)
+	}
+	var answer struct {
+		Step  string `json:"step"`
+		Key   string `json:"key"`
+		State string `json:"state"`
+	}
+	if err := json.Unmarshal(raw, &answer); err != nil {
+		return nil, fmt.Errorf("%s on %s answered what is not a step: %w", tool, node, err)
+	}
+	if answer.Key == "" {
+		return nil, fmt.Errorf("%s on %s answered no step key: %s", tool, node, raw)
+	}
+	if n, _, err := delivery.ParseStepKey(answer.Key); err != nil || n != node {
+		return nil, fmt.Errorf("%s on %s answered the step key %q, which is not a key of that node", tool, node, answer.Key)
+	}
+	wait, cancel := context.WithTimeoutCause(ctx, r.Bound, fmt.Errorf("the step %s did not end within %s", answer.Key, r.Bound))
+	defer cancel()
+	step, err := r.Steps.Wait(wait, module, answer.Key)
+	if err != nil {
+		if cause := context.Cause(wait); cause != nil && ctx.Err() == nil {
+			err = cause
+		}
+		return nil, fmt.Errorf("%s on %s: %w", tool, node, err)
+	}
+	if step.State != delivery.StepPassed {
+		return nil, fmt.Errorf("%s on %s: the step %s %s: %s", tool, node, answer.Key, step.State, step.Reason)
+	}
+	return step.Result, nil
+}

modules/mesh-delivery-builder/buildrun/steps_test.go

@@ -0,0 +1,125 @@
+package buildrun
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+type call struct {
+	node, key string
+	body      any
+}
+
+// fakeCaller answers a long tool as the build modules do: at once, with the step and its key.
+type fakeCaller struct {
+	calls  []call
+	answer string
+	err    error
+}
+
+func (f *fakeCaller) CallOn(node, key string, body any) (json.RawMessage, error) {
+	f.calls = append(f.calls, call{node, key, body})
+	if f.err != nil {
+		return nil, f.err
+	}
+	return json.RawMessage(f.answer), nil
+}
+
+// fakeSteps holds the steps values by `<module>/<key>`; Wait on a key it does not hold blocks until the context ends.
+type fakeSteps struct {
+	mu    sync.Mutex
+	steps map[string]delivery.Step
+	// during, when set, is called as a wait starts and the function it answers as the wait ends.
+	during func(key string) func()
+}
+
+func (f *fakeSteps) Wait(ctx context.Context, module, key string) (delivery.Step, error) {
+	f.mu.Lock()
+	s, ok := f.steps[module+"/"+key]
+	during := f.during
+	f.mu.Unlock()
+	if ok {
+		if during != nil {
+			defer during(key)()
+		}
+		return s, nil
+	}
+	<-ctx.Done()
+	return delivery.Step{}, context.Cause(ctx)
+}
+
+func stepAt(node, id, state, reason string, result string) delivery.Step {
+	s := delivery.Step{ID: id, Tool: "build_go_fetch", Node: node, State: state, Reason: reason}
+	if result != "" {
+		s.Result = json.RawMessage(result)
+	}
+	return s
+}
+
+func runCallsTheToolOnTheNodeAndReadsTheStepsKey(t *testing.T) { // 1607/AC5
+	caller := &fakeCaller{answer: `{"step":"abc1","key":"ace.abc1","state":"running"}`}
+	steps := &fakeSteps{steps: map[string]delivery.Step{"mesh-build-go/ace.abc1": stepAt("ace", "abc1", delivery.StepPassed, "", `{"workspace":"w1","commit":"c"}`)}}
+	res, err := Runner{Caller: caller, Steps: steps, Bound: time.Second}.Run(context.Background(), "mesh-build-go", "ace", "build_go_fetch", map[string]any{"repository": "novox/r", "commit": "c"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(caller.calls) != 1 || caller.calls[0].node != "ace" || caller.calls[0].key != "mesh-build-go.build_go_fetch" {
+		t.Errorf("calls = %+v, want one on ace for mesh-build-go.build_go_fetch", caller.calls)
+	}
+	var fr struct{ Workspace string }
+	if err := json.Unmarshal(res, &fr); err != nil || fr.Workspace != "w1" {
+		t.Errorf("result = %s (%v), want the step's result", res, err)
+	}
+}
+
+func runFailsOnAFailedOrRefusedStepNamingItsReason(t *testing.T) { // 1607/AC5
+	for _, state := range []string{delivery.StepFailed, delivery.StepRefused} {
+		caller := &fakeCaller{answer: `{"step":"abc1","key":"ace.abc1","state":"running"}`}
+		steps := &fakeSteps{steps: map[string]delivery.Step{"mesh-build-go/ace.abc1": stepAt("ace", "abc1", state, "go is go1.26.0, the recipe builds with go1.27.1", "")}}
+		_, err := Runner{Caller: caller, Steps: steps, Bound: time.Second}.Run(context.Background(), "mesh-build-go", "ace", "build_go_build", nil)
+		if err == nil || !strings.Contains(err.Error(), "go1.27.1") || !strings.Contains(err.Error(), state) || !strings.Contains(err.Error(), "ace") {
+			t.Errorf("%s: error = %v, want the node, the state and the reason", state, err)
+		}
+	}
+}
+
+func runStopsWaitingAtTheBound(t *testing.T) { // 1607/AC5
+	caller := &fakeCaller{answer: `{"step":"abc1","key":"ace.abc1","state":"running"}`}
+	_, err := Runner{Caller: caller, Steps: &fakeSteps{}, Bound: 20 * time.Millisecond}.Run(context.Background(), "mesh-build-go", "ace", "build_go_build", nil)
+	if err == nil || !strings.Contains(err.Error(), "ace.abc1") || !strings.Contains(err.Error(), "did not end") {
+		t.Errorf("error = %v, want the step key and that it did not end within its bound", err)
+	}
+}
+
+func runRefusesAnAnswerWithNoKeyAndAKeyOfAnotherNode(t *testing.T) { // 1607/AC5
+	for _, answer := range []string{`{"state":"running"}`, `{"step":"abc1","key":"novox.abc1","state":"running"}`, `not json`} {
+		_, err := Runner{Caller: &fakeCaller{answer: answer}, Steps: &fakeSteps{}, Bound: time.Second}.Run(context.Background(), "mesh-build-go", "ace", "build_go_fetch", nil)
+		if err == nil {
+			t.Errorf("answer %s: no error", answer)
+		}
+	}
+}
+
+func runReturnsTheCallsOwnError(t *testing.T) { // 1607/AC5
+	boom := errors.New("no responders")
+	_, err := Runner{Caller: &fakeCaller{err: boom}, Steps: &fakeSteps{}, Bound: time.Second}.Run(context.Background(), "mesh-build-go", "ace", "build_go_fetch", nil)
+	if !errors.Is(err, boom) || !strings.Contains(err.Error(), "ace") {
+		t.Errorf("error = %v, want the call's error naming the node", err)
+	}
+}
+
+// A step run on its node and read from its steps key, one table of cases (the test budget).
+func TestRunningAStepOnANode(t *testing.T) {
+	t.Run("run calls the tool on the node and reads the steps key", runCallsTheToolOnTheNodeAndReadsTheStepsKey)
+	t.Run("run fails on a failed or refused step naming its reason", runFailsOnAFailedOrRefusedStepNamingItsReason)
+	t.Run("run stops waiting at the bound", runStopsWaitingAtTheBound)
+	t.Run("run refuses an answer with no key and a key of another node", runRefusesAnAnswerWithNoKeyAndAKeyOfAnotherNode)
+	t.Run("run returns the calls own error", runReturnsTheCallsOwnError)
+}

modules/mesh-delivery-builder/buildrun/toolchains.go

@@ -0,0 +1,64 @@
+package buildrun
+
+import (
+	"sync"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// LanguageOf is the language each build module's toolchains state holds (the indexer's ToolchainModules, reversed).
+var LanguageOf = map[string]string{GoBuildModule: "go", NodeBuildModule: "typescript"}
+
+// ToolchainSet holds what the build modules' toolchains buckets hold: each node's entry of a language, as the watches
+// put them in. Safe for use from the watches and from a build at once.
+type ToolchainSet struct {
+	mu sync.Mutex
+	by map[string]map[string]delivery.Toolchain // language -> node -> entry
+}
+
+// Put takes a change of a build module's toolchains bucket in: a put of a node's entry (key <node>.<language>) or its
+// delete. It answers whether the language's entries changed (a node's version or recipe, or a node appearing or going).
+// A key or a value that is not an entry of the module's language is left out.
+func (s *ToolchainSet) Put(module, key string, value []byte, deleted bool) bool {
+	language, ok := LanguageOf[module]
+	if !ok {
+		return false
+	}
+	node, keyLanguage, err := delivery.ParseToolchainKey(key)
+	if err != nil || keyLanguage != language {
+		return false
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if deleted {
+		if _, had := s.by[language][node]; !had {
+			return false
+		}
+		delete(s.by[language], node)
+		return true
+	}
+	tc, err := delivery.DecodeToolchain(value)
+	if err != nil || tc.Language != language {
+		return false
+	}
+	if s.by == nil {
+		s.by = map[string]map[string]delivery.Toolchain{}
+	}
+	if s.by[language] == nil {
+		s.by[language] = map[string]delivery.Toolchain{}
+	}
+	cur, had := s.by[language][node]
+	s.by[language][node] = tc
+	return !had || cur.Version != tc.Version || cur.Recipe != tc.Recipe
+}
+
+// Entries are the nodes' entries of a language, in no particular order.
+func (s *ToolchainSet) Entries(language string) []delivery.NodeToolchain {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	var out []delivery.NodeToolchain
+	for node, tc := range s.by[language] {
+		out = append(out, delivery.NodeToolchain{Node: node, Toolchain: tc})
+	}
+	return out
+}

modules/mesh-delivery-builder/buildrun/toolchains_test.go

@@ -0,0 +1,49 @@
+package buildrun
+
+import (
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func tcValue(t *testing.T, language, version string) []byte {
+	t.Helper()
+	b, err := delivery.EncodeToolchain(delivery.Toolchain{Language: language, Version: version, Recipe: "1", At: time.Now()})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return b
+}
+
+func TestToolchainSetKeepsEachNodesEntryByLanguageAndSaysWhenOneChanged(t *testing.T) { // 1607/AC6
+	var s ToolchainSet
+	if !s.Put(GoBuildModule, "novox.go", tcValue(t, "go", "go1.27.1"), false) {
+		t.Error("a first entry did not count as a change")
+	}
+	if s.Put(GoBuildModule, "novox.go", tcValue(t, "go", "go1.27.1"), false) {
+		t.Error("the same entry again counted as a change")
+	}
+	s.Put(GoBuildModule, "ace.go", tcValue(t, "go", "go1.27.1"), false)
+	s.Put(NodeBuildModule, "ace.typescript", tcValue(t, "typescript", "tsc5"), false)
+	if got := s.Entries("go"); len(got) != 2 {
+		t.Errorf("go entries = %+v, want two", got)
+	}
+	if got := s.Entries("typescript"); len(got) != 1 || got[0].Node != "ace" || got[0].Version != "tsc5" {
+		t.Errorf("typescript entries = %+v", got)
+	}
+	if !s.Put(GoBuildModule, "ace.go", nil, true) || len(s.Entries("go")) != 1 {
+		t.Error("a delete did not remove the node's entry")
+	}
+	// What is not a toolchain of the module's language is left out.
+	s = ToolchainSet{}
+	if s.Put(GoBuildModule, "novox.typescript", tcValue(t, "typescript", "x"), false) {
+		t.Error("a typescript toolchain in the go build module's bucket counted")
+	}
+	if s.Put(GoBuildModule, "novox.go", []byte("not json"), false) || s.Put("other-module", "novox.go", tcValue(t, "go", "x"), false) {
+		t.Error("garbage or an unknown module counted")
+	}
+	if len(s.Entries("go")) != 0 {
+		t.Error("an entry was kept")
+	}
+}

modules/mesh-delivery-builder/cmd/mesh-delivery-builder-tools/main.go

@@ -14,9 +14,9 @@ import (
 	"sync"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	stdio "git.novox.be/novox/mesh-sdk/go"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 
 	"mesh-delivery-builder/internal/build"
 )

modules/mesh-delivery-builder/cmd/mesh-delivery-builder/integration_test.go

@@ -22,6 +22,9 @@ import (
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
+	// The build runner the build modules pull and run asks with: mesh-build-go's own package (novox/hq ADR 0593 §1),
+	// another repository's, by its published version, so the builder is tested against the real pulling code.
+	runner "git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
@@ -53,7 +56,7 @@ const (
 )
 
 // fakeBuildModules are the build modules on the nodes as the real ones run since R4g (ADR 0525; issue 1887 A4): each pulls
-// its build seat's asks on its nodes (buildstep.Puller over the seat's workers) and runs an ask's job with step bodies that
+// its build seat's asks on its nodes (runner.Puller over the seat's workers) and runs an ask's job with step bodies that
 // answer as the real tools do, ending the step on <node>.<ask id> of its steps bucket.
 type fakeBuildModules struct {
 	js        jetstream.JetStream
@@ -68,14 +71,14 @@ type fakeBuildModules struct {
 	// closed, while set, keeps every node's capacity at 0: no ask is pulled until open is called (a test of the asks
 	// waiting in their streams).
 	closed  atomic.Bool
-	pullers []*buildstep.Puller
+	pullers []*runner.Puller
 }
 
 // open lets the nodes pull again and wakes their pullers.
 func (f *fakeBuildModules) open() {
 	f.closed.Store(false)
 	f.mu.Lock()
-	ps := append([]*buildstep.Puller(nil), f.pullers...)
+	ps := append([]*runner.Puller(nil), f.pullers...)
 	f.mu.Unlock()
 	for _, p := range ps {
 		p.Wake()
@@ -139,26 +142,26 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, nodes ...string) {
 		t.Fatal(err)
 	}
 	language := strings.TrimPrefix(module, "mesh-build-")
-	if err := buildstep.DeclareAskWorkers(f.ctx, f.js, language, 30*time.Second); err != nil {
+	if err := runner.DeclareAskWorkers(f.ctx, f.js, language, 30*time.Second); err != nil {
 		t.Fatal(err)
 	}
 	put := func(key string, value any) (uint64, error) {
 		raw, _ := value.(json.RawMessage)
 		return kv.Put(f.ctx, key, raw)
 	}
-	call := func(name string) buildstep.StepFunc {
+	call := func(name string) runner.StepFunc {
 		return func(ctx context.Context, args map[string]any) (any, error) { return f.step(module, name, args) }
 	}
-	steps := buildstep.AskSteps{Fetch: call("fetch"), Build: call("build"), Copy: call("copy")}
+	steps := runner.AskSteps{Fetch: call("fetch"), Build: call("build"), Copy: call("copy")}
 	for _, node := range nodes {
-		p := &buildstep.Puller{Source: &buildstep.JetStreamAsks{JS: f.js, Language: language}, Language: language, Node: node, Put: put,
+		p := &runner.Puller{Source: &runner.JetStreamAsks{JS: f.js, Language: language}, Language: language, Node: node, Put: put,
 			Capacity: func() int {
 				if f.closed.Load() {
 					return 0
 				}
 				return 2
 			}, PullWait: 200 * time.Millisecond,
-			Run: func(ctx context.Context, a delivery.StepAsk) (any, error) { return buildstep.RunAsk(ctx, steps, a) }}
+			Run: func(ctx context.Context, a delivery.StepAsk) (any, error) { return runner.RunAsk(ctx, steps, a) }}
 		f.mu.Lock()
 		f.pullers = append(f.pullers, p)
 		f.mu.Unlock()

modules/mesh-delivery-builder/cmd/mesh-delivery-builder/main.go

@@ -18,7 +18,7 @@ import (
 	"syscall"
 	"time"
 
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"

modules/mesh-delivery-builder/cmd/mesh-delivery-builder/refused_test.go

@@ -12,8 +12,8 @@ import (
 
 	"github.com/nats-io/nats.go/jetstream"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // 1945 (a part exits at start for a bucket it works without): a bus that refuses every toolchains bucket leaves the

modules/mesh-delivery-builder/cmd/mesh-delivery-builder/toolchains.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 	"sync"
 
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/process"
 
 	"github.com/nats-io/nats.go/jetstream"

modules/mesh-delivery-builder/go.mod

@@ -3,12 +3,15 @@ module mesh-delivery-builder
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )
 
+require git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9
+
 require (
+	git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun v0.0.0-00010101000000-000000000000
 	github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op // indirect
 	github.com/google/go-tpm v0.9.8 // indirect
 	github.com/klauspost/compress v1.20.0 // indirect
@@ -20,3 +23,5 @@ require (
 	golang.org/x/sys v0.48.0 // indirect
 	golang.org/x/time v0.15.0 // indirect
 )
+
+replace git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun => ./buildrun

modules/mesh-delivery-builder/go.sum

@@ -1,5 +1,7 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791 h1:7SYIDPMxbPBr8dMB6k9fYsgVt4ZyWVL41q4LMFsfAvs=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102112556-abf5eace7791/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9 h1:DrwGUXwv3A4KTiUjepbZMNumoillbMfYrKBEl9EZiOc=
+git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9/go.mod h1:kpsX4Pgss5EeuBvel1zWa2ogj7MkR3jZso6oa/J0YUQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128 h1:aI1DhZAuqVBXbybSqhLNOGX5rUOrn9T0cHNCDUQF7IQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=

modules/mesh-delivery-builder/internal/build/askagain.go

@@ -11,9 +11,9 @@ import (
 	"strings"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // **An ask that can no longer be answered is asked again** (novox/hq issue 1945). A build seat's stream gives an ask up

modules/mesh-delivery-builder/internal/build/askfake_test.go

@@ -0,0 +1,94 @@
+package build
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"maps"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// The build runner a build node runs an ask with is mesh-build-go's (novox/hq ADR 0593 §1), another repository's,
+// which the builder does not import. These tests run an ask as the builder needs it run: fetch once at the job's
+// fetch arguments with its package versions, build or copy each artifact, answer each one's digest and reference. They
+// test the builder, not the runner.
+
+// stepFunc is one step of a build module, as its tool answers it.
+type stepFunc func(ctx context.Context, args map[string]any) (any, error)
+
+// askSteps are a build module's steps an ask is run with.
+type askSteps struct{ Fetch, Build, Copy stepFunc }
+
+// runAsk runs a build ask with steps and answers its delivery.BuildAnswer, or the error that fails the step.
+func runAsk(ctx context.Context, steps askSteps, ask delivery.StepAsk) (any, error) {
+	if ask.Build == nil {
+		return nil, fmt.Errorf("the ask %s holds no build job", ask.ID)
+	}
+	job := *ask.Build
+	fetch := job.Fetch
+	if len(ask.Packages) > 0 && fetch != nil {
+		fetch = maps.Clone(fetch)
+		fetch["packages"] = maps.Clone(ask.Packages)
+	}
+	answer := delivery.BuildAnswer{}
+	workspace := ""
+	for _, a := range job.Artifacts {
+		var out any
+		var err error
+		if a.From != "" {
+			if steps.Copy == nil {
+				return nil, fmt.Errorf("this build module copies no artifact (%s)", a.Artifact)
+			}
+			out, err = steps.Copy(ctx, map[string]any{"module": job.Module, "artifact": a.Artifact, "from": a.From})
+		} else {
+			if workspace == "" {
+				raw, err := asRaw(steps.Fetch(ctx, fetch))
+				if err != nil {
+					return nil, err
+				}
+				var f struct {
+					Workspace string   `json:"workspace"`
+					Merge     string   `json:"merge"`
+					Conflicts []string `json:"conflicts"`
+				}
+				if err := json.Unmarshal(raw, &f); err != nil || f.Workspace == "" {
+					return nil, fmt.Errorf("the fetch answered no workspace: %s", raw)
+				}
+				if _, candidate := fetch["base"]; candidate && (len(f.Conflicts) > 0 || f.Merge == "") {
+					return nil, fmt.Errorf("the head does not merge into the trunk: %s", strings.Join(f.Conflicts, ", "))
+				}
+				workspace = f.Workspace
+			}
+			args := map[string]any{"workspace": workspace, "module": job.Path, "artifact": a.Artifact}
+			if job.Publish {
+				args["publish"] = true
+			}
+			out, err = steps.Build(ctx, args)
+		}
+		raw, err := asRaw(out, err)
+		if err != nil {
+			return nil, fmt.Errorf("%s: %w", a.Artifact, err)
+		}
+		var built struct {
+			Digest    string `json:"digest"`
+			Reference string `json:"reference"`
+		}
+		if err := json.Unmarshal(raw, &built); err != nil || built.Digest == "" {
+			return nil, fmt.Errorf("the build of %s answered no digest: %s", a.Artifact, raw)
+		}
+		answer.Artifacts = append(answer.Artifacts, delivery.AskBuilt{Artifact: a.Artifact, Digest: built.Digest, Reference: built.Reference})
+	}
+	return answer, nil
+}
+
+func asRaw(v any, err error) (json.RawMessage, error) {
+	if err != nil {
+		return nil, err
+	}
+	if r, ok := v.(json.RawMessage); ok {
+		return r, nil
+	}
+	return json.Marshal(v)
+}

modules/mesh-delivery-builder/internal/build/buildagain.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // **A failed key is built again by hand** (novox/hq issue 1126 note 72; ADR 0429 clause 18: "a fingerprint is built again

modules/mesh-delivery-builder/internal/build/candidates.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"sort"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // How a candidate's fingerprint is built (novox/hq ADR 0484 clause 3, issue 1684): the indexer writes, for each module a

modules/mesh-delivery-builder/internal/build/claim.go

@@ -8,9 +8,9 @@ import (
 	"sort"
 	"strings"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // ErrConflict is what a Store answers when a Create finds the key or an Update finds another revision than the one given.

modules/mesh-delivery-builder/internal/build/fixtures_test.go

@@ -29,7 +29,7 @@ func captured(t *testing.T, name string) json.RawMessage {
 	return step.Result
 }
 
-// The captured image steps, run as a pulled ask runs them (buildstep.RunAsk), answer what the builder reads: the trunk's
+// The captured image steps, run as a pulled ask runs them (runAsk), answer what the builder reads: the trunk's
 // build its digest and reference, a candidate's its digest and no reference (issue 1887 A4a).
 func TestCapturedImageStepsDecodeWithTheBuildersOwnTypes(t *testing.T) { // review r2, mesh-catalog 2; ADR 0487 clause 1
 	for _, tc := range []struct {
@@ -37,7 +37,7 @@ func TestCapturedImageStepsDecodeWithTheBuildersOwnTypes(t *testing.T) { // revi
 		publish bool
 		ref     bool
 	}{{"build-trunk.json", true, true}, {"build-candidate.json", false, false}} {
-		steps := buildstep.AskSteps{
+		steps := askSteps{
 			Fetch: func(context.Context, map[string]any) (any, error) {
 				return json.RawMessage(captured(t, "fetch.json")), nil
 			},
@@ -47,7 +47,7 @@ func TestCapturedImageStepsDecodeWithTheBuildersOwnTypes(t *testing.T) { // revi
 			At: time.Now(), Build: &delivery.BuildJob{Module: "m", Path: "modules/m", Publish: tc.publish,
 				Fetch:     map[string]any{"repository": "novox/mesh-catalog", "commit": strings.Repeat("a", 40)},
 				Artifacts: []delivery.AskArtifact{{Artifact: "server"}}}}
-		out, err := buildstep.RunAsk(context.Background(), steps, ask)
+		out, err := runAsk(context.Background(), steps, ask)
 		if err != nil {
 			t.Fatalf("%s: %v", tc.build, err)
 		}

modules/mesh-delivery-builder/internal/build/imports_test.go

@@ -0,0 +1,36 @@
+package build
+
+import (
+	"encoding/json"
+	"strings"
+	"sync"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// ADR 0593 §2 (F3): the imports a Go build module answers at a build's end reach the done key and the log's end entry,
+// where the indexer keeps them on the module.
+func importsABuildAnswersReachTheDoneKeyAndTheLog(t *testing.T) {
+	r := newRig(t, goBundle)
+	imports := []string{"git.novox.be/novox/mesh-sdk/go", "git.novox.be/novox/mesh-sdk/go/announce"}
+	r.asks.Answer = func(a delivery.StepAsk) delivery.Step {
+		step := r.answer(a)
+		var answer map[string]any
+		if err := json.Unmarshal(step.Result, &answer); err == nil && a.Language == "go" {
+			answer["imports"] = imports
+			step.Result, _ = json.Marshal(answer)
+		}
+		return step
+	}
+	var logged []delivery.BuildLogEntry
+	var mu sync.Mutex
+	r.b.Node, r.b.Log = "novox", func(e delivery.BuildLogEntry) { mu.Lock(); logged = append(logged, e); mu.Unlock() }
+	v := r.consider(t, "modules/m")
+	if v.State != delivery.BuildDone || strings.Join(v.Imports, ",") != strings.Join(imports, ",") {
+		t.Fatalf("done key %+v, want the imports", v)
+	}
+	if len(logged) != 2 || strings.Join(logged[1].Imports, ",") != strings.Join(imports, ",") || len(logged[0].Imports) != 0 {
+		t.Fatalf("log %+v, want the imports on the end alone", logged)
+	}
+}

modules/mesh-delivery-builder/internal/build/plan.go

@@ -8,9 +8,9 @@ import (
 	"sort"
 	"strings"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // ImageBuildModule is the build module that builds an image artifact (novox/hq ADR 0487): buildah, rootless, on the nodes that

modules/mesh-delivery-builder/internal/build/plan_test.go

@@ -3,8 +3,8 @@ package build
 import (
 	"errors"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"strings"
 	"testing"
 

modules/mesh-delivery-builder/internal/build/r4e_test.go

@@ -305,10 +305,9 @@ func TestTheFetchOfAModuleNamingItsPathsCarriesItsDirectoryAndThosePaths(t *test
 	r := newRig(t, tsPackage)
 	r.bm.packages["lib"] = "@novox/mesh-sdk@0.1.15"
 	paths := map[string]string{"src": hex40('1'), "package.json": hex40('2')}
-	tree, err := delivery.NamedTree(manifestD, paths)
-	if err != nil {
-		t.Fatal(err)
-	}
+	// The named tree the indexer computes from those paths (its own, ADR 0593 §2), given as data: the builder reads it,
+	// never computes it.
+	const tree = delivery.NamedTreePrefix + "5b5e0f3b6f3c1f2a9d8e7c6b5a4938271605f4e3d2c1b0a9f8e7d6c5b4a39281"
 	data, err := delivery.EncodeModule(delivery.Module{Repository: "novox/mesh-sdk", Commit: "7a74cee83f88e6585a5511c3cc53bdf0f5303d20", FP2: fp1, Manifest: manifestD, Path: ".",
 		Toolchains: agreedToolchains, Inputs2: &delivery.KeptInputs2{Tree: tree, Paths: paths}})
 	if err != nil {

modules/mesh-delivery-builder/internal/build/round4_test.go

@@ -2,7 +2,7 @@ package build
 
 import (
 	"context"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"testing"
 
 	"git.novox.be/novox/mesh-sdk/go/catalogue"

modules/mesh-delivery-builder/internal/build/run.go

@@ -6,16 +6,17 @@ import (
 	"errors"
 	"fmt"
 	"maps"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // ToolchainEntries are the nodes' toolchain entries of a language (buildrun.ToolchainSet).
@@ -533,6 +534,7 @@ type lane struct {
 	toolchain    *delivery.ToolchainUsed
 	digests      map[string]string // artifact -> digest
 	references   map[string]string // artifact -> the reference an image was pushed to (a trunk build only)
+	imports      []string          // the mesh packages the lane's programs import, as its build module answered them
 	err          error
 }
 
@@ -666,7 +668,8 @@ func (b *Builder) build(ctx context.Context, module string, m delivery.Module, p
 	if len(used) == 0 {
 		used = nil
 	}
-	done := delivery.BuilderBuild{State: delivery.BuildDone, By: b.Claimer.By, Manifest: m.Manifest, Step: step, Artifacts: artifacts, Toolchains: used}
+	done := delivery.BuilderBuild{State: delivery.BuildDone, By: b.Claimer.By, Manifest: m.Manifest, Step: step, Artifacts: artifacts, Toolchains: used,
+		Imports: importsOf(lanes)}
 	if _, err := delivery.EncodeBuilderBuild(done); err != nil {
 		// A reference the build module answered that does not name the artifact and its digest is no reference.
 		return failed("%s%v", delivery.NotStored, err)
@@ -866,6 +869,7 @@ func (b *Builder) runLane(ctx context.Context, l *lane, repository string, m del
 		l.err = fmt.Errorf("the ask of %s on %s answered what is not a build: %s", l.module, step.Node, step.Result)
 		return
 	}
+	l.imports = answer.Imports
 	built := map[string]delivery.AskBuilt{}
 	for _, a := range answer.Artifacts {
 		built[a.Artifact] = a
@@ -950,9 +954,26 @@ func LogEnded(module string, m delivery.Module, ref, by string, at time.Time, re
 		e.Against = append([]string(nil), m.Inputs2.Bases...)
 	}
 	e.Made = append([]delivery.BuiltArtifact(nil), result.Artifacts...)
+	e.Imports = append([]string(nil), result.Imports...) // the indexer keeps them on the module (novox/hq ADR 0593 §2)
 	return e
 }
 
+// importsOf are the mesh packages the lanes' programs import, as their build modules answered them (novox/hq ADR 0593
+// §2): sorted and each once; nil when none answered any. A lane kept from a prior build answered none, so a build that
+// kept one reports only what it built.
+func importsOf(lanes []*lane) []string {
+	seen := map[string]bool{}
+	for _, l := range lanes {
+		for _, p := range l.imports {
+			seen[p] = true
+		}
+	}
+	if len(seen) == 0 {
+		return nil
+	}
+	return slices.Sorted(maps.Keys(seen))
+}
+
 // SittingOutWords says, per node that is not on the agreed toolchain of a language, that it sits out and which version
 // it has against the agreed one: "ace sits out: typescript 26.12.1, agreed 26.13.0" (novox/hq ADR 0584 clause 2).
 func SittingOutWords(language string, a delivery.Agreement) []string {

modules/mesh-delivery-builder/internal/build/run_test.go

@@ -13,11 +13,10 @@ import (
 	"testing"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	stdio "git.novox.be/novox/mesh-sdk/go"
-	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // buildModules simulates the two build modules on the nodes: a long tool answers a step and key at once and writes the
@@ -140,7 +139,7 @@ type rig struct {
 // toolPrefix is the start of each build module's tool names, as the fake build modules answer them.
 var toolPrefix = map[string]string{buildrun.GoBuildModule: "build_go_", buildrun.NodeBuildModule: "build_node_", ImageBuildModule: "build_image_"}
 
-// answer runs an ask as the build module that pulls it does (buildstep.RunAsk), with the fake build modules' tools on the
+// answer runs an ask as the build module that pulls it does (runAsk), with the fake build modules' tools on the
 // rig's pulling node, and answers the step that node writes.
 func (r *rig) answer(a delivery.StepAsk) delivery.Step {
 	node := r.puller
@@ -149,7 +148,7 @@ func (r *rig) answer(a delivery.StepAsk) delivery.Step {
 	}
 	module, _ := delivery.BuildModuleOf(a.Language)
 	runner := buildrun.Runner{Caller: r.bm, Steps: r.bm.steps, Bound: time.Second}
-	tool := func(name string) buildstep.StepFunc {
+	tool := func(name string) stepFunc {
 		return func(ctx context.Context, args map[string]any) (any, error) {
 			raw, err := runner.Run(ctx, module, node, toolPrefix[module]+name, args)
 			if err != nil {
@@ -158,8 +157,8 @@ func (r *rig) answer(a delivery.StepAsk) delivery.Step {
 			return raw, nil
 		}
 	}
-	steps := buildstep.AskSteps{Fetch: tool("fetch"), Build: tool("build"), Copy: tool("copy")}
-	out, err := buildstep.RunAsk(context.Background(), steps, a)
+	steps := askSteps{Fetch: tool("fetch"), Build: tool("build"), Copy: tool("copy")}
+	out, err := runAsk(context.Background(), steps, a)
 	step := delivery.Step{ID: a.ID, Tool: a.Kind + " ask", Node: node, State: delivery.StepPassed}
 	if err != nil {
 		step.State, step.Reason = delivery.StepFailed, err.Error()
@@ -222,6 +221,7 @@ var (
 )
 
 func TestABundleAndAnArchiveAreBuiltOnOneNodeAndDone(t *testing.T) { // 1607/AC7, ADR 0478 clauses 1, 4
+	t.Run("the imports a build answers reach the done key and the log", importsABuildAnswersReachTheDoneKeyAndTheLog)
 	r := newRig(t, goBundle, archiveA, tsBundle)
 	// ADR 0584: a third node agrees with novox and ace's typescript is the odd one; the build is done and its step says ace sits out.
 	r.tools.Put(buildrun.NodeBuildModule, "g14.typescript", tcValue(t, "typescript", "tsc5"), false)

modules/mesh-delivery-builder/internal/build/stuck.go

@@ -11,8 +11,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // The builder's tools (novox/hq issue 1945; the instruction "tools are how a module is spoken to"): builder_stuck reads

modules/mesh-delivery-checker/cmd/mesh-delivery-checker-tools/main.go

@@ -10,9 +10,9 @@ import (
 	"sync/atomic"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	stdio "git.novox.be/novox/mesh-sdk/go"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 
 	"mesh-delivery-checker/internal/check"
 )

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/composition_line_integration_test.go

@@ -1,64 +0,0 @@
-//go:build integration
-
-package main
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/nats-io/nats.go/jetstream"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-// assignerWrote raises the assigner's compositions bucket, the assigner online in the watchman's presence, and its verdict
-// under the check's key, as the assigner leaves them on the bus.
-func (b *bed) assignerWrote(t *testing.T, key string, v delivery.CompositionVerdict) {
-	t.Helper()
-	kv, err := b.js.CreateKeyValue(b.ctx, jetstream.KeyValueConfig{Bucket: delivery.AssignerCompositionsBucket, History: delivery.AssignerCompositionsHistory})
-	if err != nil {
-		t.Fatal(err)
-	}
-	pkey, _ := delivery.PresencePartKey(delivery.AssignerModule, "novox")
-	on, _ := delivery.EncodePresence(delivery.Presence{Online: true})
-	if _, err := b.buckets[delivery.PresenceBucket].Put(b.ctx, pkey, on); err != nil {
-		t.Fatal(err)
-	}
-	data, err := delivery.EncodeCompositionVerdict(v)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if _, err := kv.Put(b.ctx, key, data); err != nil {
-		t.Fatal(err)
-	}
-}
-
-// 1297/AC3: started whole with the assigner's verdict on the bus, the checker's line says the composition's verdict, not
-// "not yet run": a pass names its machine, a fail fails the check with the assigner's words.
-func TestTheCheckersLineSaysTheAssignersComposition(t *testing.T) {
-	t.Run("the read awaits the assigner's composition", checkerAwaitsTheAssignersComposition)
-	for _, c := range []struct {
-		state, owed, words string
-	}{
-		{delivery.CompositionPass, "success", "composition passed"},
-		{delivery.CompositionFail, "failure", "g14 runs web, which the change removes from its source"},
-	} {
-		b := startBed(t)
-		key := b.candidate(t, "feat/x", pull(repo, 7, head1))
-		group, heads, _ := delivery.ParseCheckerVerdictKey(key)
-		v := delivery.CompositionVerdict{Group: group, Heads: heads, State: c.state, SDK: "v0.1.14-x", Machines: []string{"g14"}}
-		if c.state == delivery.CompositionFail {
-			v.Machine, v.Words = "g14", c.words
-		}
-		b.assignerWrote(t, key, v)
-		b.start(t, nil)
-		got := b.verdict(t, key, ended)
-		if got.Composition == nil || got.Composition.State != c.state {
-			t.Fatalf("%s: the verdict's composition is %+v", c.state, got.Composition)
-		}
-		o := b.owed(t, 7, head1, c.owed)
-		if !strings.Contains(o.Text, c.words) || strings.Contains(o.Text, "not yet run") {
-			t.Errorf("%s: the line says %q", c.state, o.Text)
-		}
-	}
-}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/compositions.go

@@ -1,131 +0,0 @@
-package main
-
-import (
-	"context"
-	"errors"
-	"sync"
-
-	"github.com/nats-io/nats.go/jetstream"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-
-	"mesh-delivery-checker/internal/check"
-)
-
-// compositionWatch reads the assigner's composition of a check (ADR 0528 clause 5) by watching its key and the
-// assigner's presence: no poll and no timer. With no assigner online it answers check.ErrAssignerNotRunning at once.
-type compositionWatch struct {
-	kv jetstream.KeyValue
-	// presence is the watchman's presence bucket; nil (not there) counts as no assigner online.
-	presence jetstream.KeyValue
-}
-
-// Await answers the composition under key once the assigner wrote one that does not wait (check.AwaitComposition).
-func (c compositionWatch) Await(ctx context.Context, key string) (delivery.CompositionVerdict, error) {
-	ctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-	comps := make(chan check.CompositionEvent)
-	presence := make(chan check.PresenceEvent)
-	cw, err := c.kv.Watch(ctx, key)
-	if err != nil {
-		return delivery.CompositionVerdict{}, err
-	}
-	defer cw.Stop()
-	go func() {
-		for e := range cw.Updates() {
-			ev := check.CompositionEvent{Settled: e == nil}
-			if e != nil && e.Operation() == jetstream.KeyValuePut {
-				ev.Value = e.Value()
-			}
-			select {
-			case comps <- ev:
-			case <-ctx.Done():
-				return
-			}
-		}
-	}()
-	if c.presence == nil {
-		go func() {
-			select {
-			case presence <- check.PresenceEvent{Settled: true}:
-			case <-ctx.Done():
-			}
-		}()
-	} else {
-		pw, err := c.presence.Watch(ctx, "part."+delivery.AssignerModule+".*")
-		if err != nil {
-			return delivery.CompositionVerdict{}, err
-		}
-		defer pw.Stop()
-		go func() {
-			for e := range pw.Updates() {
-				ev := check.PresenceEvent{Settled: e == nil}
-				if e != nil {
-					ev.Key = e.Key()
-					if e.Operation() == jetstream.KeyValuePut {
-						if p, err := delivery.DecodePresence(e.Value()); err == nil {
-							ev.Online = p.Online
-						}
-					}
-				}
-				select {
-				case presence <- ev:
-				case <-ctx.Done():
-					return
-				}
-			}
-		}()
-	}
-	return check.AwaitComposition(ctx, presence, comps)
-}
-
-// followCompositions hands the checker each composition the assigner writes from now on, so a verdict that said its
-// composition was not judged takes it in when the assigner starts (event-driven).
-func followCompositions(ctx context.Context, kv jetstream.KeyValue, ch *check.Checker) error {
-	w, err := kv.WatchAll(ctx, jetstream.UpdatesOnly())
-	if err != nil {
-		return err
-	}
-	go func() {
-		defer w.Stop()
-		for e := range w.Updates() {
-			if e == nil || e.Operation() != jetstream.KeyValuePut {
-				continue
-			}
-			if comp, err := delivery.DecodeCompositionVerdict(e.Value()); err == nil {
-				ch.Composed(ctx, comp)
-			}
-		}
-	}()
-	return nil
-}
-
-// lazyCompositions opens the assigner's compositions when a check first asks for one and the bucket is there: until it
-// is, no assigner ever ran, so the check says at once that its composition is not judged (check.ErrAssignerNotRunning),
-// and the next check looks again. No timer: each look is a check asking.
-type lazyCompositions struct {
-	open func(ctx context.Context) (check.CompositionReader, error)
-
-	mu     sync.Mutex
-	reader check.CompositionReader
-}
-
-// Await is the opened reader's Await, opening it first when it is not yet.
-func (l *lazyCompositions) Await(ctx context.Context, key string) (delivery.CompositionVerdict, error) {
-	l.mu.Lock()
-	r := l.reader
-	if r == nil {
-		opened, err := l.open(ctx)
-		switch {
-		case errors.Is(err, jetstream.ErrBucketNotFound):
-			l.mu.Unlock()
-			return delivery.CompositionVerdict{}, check.ErrAssignerNotRunning
-		case err != nil:
-			l.mu.Unlock()
-			return delivery.CompositionVerdict{}, err
-		}
-		l.reader, r = opened, opened
-	}
-	l.mu.Unlock()
-	return r.Await(ctx, key)
-}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/compositions_integration_test.go

@@ -1,107 +0,0 @@
-//go:build integration
-
-package main
-
-import (
-	"context"
-	"errors"
-	"os"
-	"path/filepath"
-	"testing"
-	"time"
-
-	"github.com/nats-io/nats-server/v2/server"
-	"github.com/nats-io/nats.go"
-	"github.com/nats-io/nats.go/jetstream"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-
-	"mesh-delivery-checker/internal/check"
-)
-
-// 1297/AC3 (its bus half): on the real bus, the checker's read of the assigner's composition waits while the key is
-// absent and while the assigner says it waits, and answers the verdict the assigner then writes under the check's key.
-// A case of TestTheCheckersLineSaysTheAssignersComposition (merged into it for the test budget, issue 774).
-func checkerAwaitsTheAssignersComposition(t *testing.T) {
-	dir, err := os.MkdirTemp(os.Getenv("TMPDIR"), "comp")
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(func() { os.RemoveAll(dir) })
-	srv, err := server.NewServer(&server.Options{Host: "127.0.0.1", Port: -1, JetStream: true, StoreDir: filepath.Join(dir, "js"), NoLog: true, NoSigs: true})
-	if err != nil {
-		t.Fatal(err)
-	}
-	go srv.Start()
-	if !srv.ReadyForConnections(10 * time.Second) {
-		t.Fatal("the bus did not come up")
-	}
-	t.Cleanup(srv.Shutdown)
-	nc, err := nats.Connect(srv.ClientURL())
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(nc.Close)
-	js, _ := jetstream.New(nc)
-	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
-	defer cancel()
-	kv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: delivery.AssignerCompositionsBucket, History: delivery.AssignerCompositionsHistory})
-	if err != nil {
-		t.Fatal(err)
-	}
-	pkv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: delivery.PresenceBucket, History: 5})
-	if err != nil {
-		t.Fatal(err)
-	}
-	pkey, _ := delivery.PresencePartKey(delivery.AssignerModule, "novox")
-	on, _ := delivery.EncodePresence(delivery.Presence{Online: true})
-	if _, err := pkv.Put(ctx, pkey, on); err != nil {
-		t.Fatal(err)
-	}
-	// With no assigner online the wait answers at once (a second key, before the assigner of this test is online).
-	off, _ := delivery.EncodePresence(delivery.Presence{Online: false})
-	if _, err := pkv.Put(ctx, pkey, off); err != nil {
-		t.Fatal(err)
-	}
-	other, _ := delivery.CompositionKey("feat/y", "0123456789ab")
-	if _, err := (compositionWatch{kv: kv, presence: pkv}).Await(ctx, other); !errors.Is(err, check.ErrAssignerNotRunning) {
-		t.Fatalf("with no assigner online the wait answered %v", err)
-	}
-	if _, err := pkv.Put(ctx, pkey, on); err != nil {
-		t.Fatal(err)
-	}
-	key, _ := delivery.CompositionKey("feat/x", "0123456789ab")
-	got := make(chan delivery.CompositionVerdict, 1)
-	go func() {
-		v, err := compositionWatch{kv: kv, presence: pkv}.Await(ctx, key)
-		if err != nil {
-			t.Error(err)
-		}
-		got <- v
-	}()
-	put := func(v delivery.CompositionVerdict) {
-		data, err := delivery.EncodeCompositionVerdict(v)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if _, err := kv.Put(ctx, key, data); err != nil {
-			t.Fatal(err)
-		}
-	}
-	time.Sleep(200 * time.Millisecond)
-	put(delivery.CompositionVerdict{Group: "feat/x", Heads: "0123456789ab", State: delivery.CompositionWaits, Words: "the indexer holds no candidates yet"})
-	select {
-	case v := <-got:
-		t.Fatalf("a waiting composition was answered: %+v", v)
-	case <-time.After(300 * time.Millisecond):
-	}
-	put(delivery.CompositionVerdict{Group: "feat/x", Heads: "0123456789ab", State: delivery.CompositionPass, SDK: "x", Machines: []string{"g14"}})
-	select {
-	case v := <-got:
-		if v.State != delivery.CompositionPass || v.Machines[0] != "g14" {
-			t.Errorf("answered %+v", v)
-		}
-	case <-time.After(5 * time.Second):
-		t.Fatal("the composition written was not answered")
-	}
-}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/compositions_test.go

@@ -1,46 +0,0 @@
-package main
-
-import (
-	"context"
-	"errors"
-	"testing"
-
-	"github.com/nats-io/nats.go/jetstream"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-
-	"mesh-delivery-checker/internal/check"
-)
-
-type answering struct{ v delivery.CompositionVerdict }
-
-func (a answering) Await(context.Context, string) (delivery.CompositionVerdict, error) {
-	return a.v, nil
-}
-
-// 1297 review item 3: the compositions bucket missing when the checker starts is looked up again at the next check: while
-// it is missing a check says at once the assigner is not running; once it is there the check reads its composition, and
-// it is opened once.
-func TestTheCompositionsBucketIsLookedUpAtEachCheck(t *testing.T) {
-	opens, there := 0, false
-	l := &lazyCompositions{open: func(context.Context) (check.CompositionReader, error) {
-		opens++
-		if !there {
-			return nil, jetstream.ErrBucketNotFound
-		}
-		return answering{delivery.CompositionVerdict{State: delivery.CompositionPass, SDK: "x"}}, nil
-	}}
-	if _, err := l.Await(context.Background(), "k"); !errors.Is(err, check.ErrAssignerNotRunning) {
-		t.Fatalf("without the bucket: %v", err)
-	}
-	there = true
-	for range 2 {
-		v, err := l.Await(context.Background(), "k")
-		if err != nil || v.State != delivery.CompositionPass {
-			t.Fatalf("with the bucket: %+v, %v", v, err)
-		}
-	}
-	if opens != 2 {
-		t.Errorf("opened %d times, want twice (missing, then once)", opens)
-	}
-}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/engines.go

@@ -0,0 +1,142 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
+	"git.novox.be/novox/mesh-sdk/go/buildstep"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/composer"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// The checker's composition of a check on the bus (novox/hq ADR 0593 §7, §9; check.EngineCompositions): each placed
+// node's engine asked `node-engine.compose-candidate` on that node, and, for a group that changes the node-engine's
+// composition code, the composer built from its head run on the Go build seat.
+
+// composeCandidateKey is the seat verb's call key, asked of one node (process.Conn.CallOn).
+var composeCandidateKey = "seat:" + catalogue.EngineSeat + "." + delivery.EngineComposeCandidateVerb
+
+// engineAsks asks one node's engine over the bus, its answer waited for at most ctx's deadline (the answer bound).
+type engineAsks struct {
+	call func(node, key string, body any) (json.RawMessage, error)
+}
+
+func (e engineAsks) ComposeCandidate(ctx context.Context, node string, ask delivery.ComposeCandidateAsk) (delivery.ComposeCandidateAnswer, error) {
+	type answer struct {
+		raw json.RawMessage
+		err error
+	}
+	got := make(chan answer, 1)
+	go func() {
+		raw, err := e.call(node, composeCandidateKey, ask)
+		got <- answer{raw, err}
+	}()
+	select {
+	case <-ctx.Done():
+		return delivery.ComposeCandidateAnswer{}, fmt.Errorf("no answer within its bound: %w", ctx.Err())
+	case a := <-got:
+		if a.err != nil {
+			return delivery.ComposeCandidateAnswer{}, a.err
+		}
+		return delivery.DecodeComposeCandidateAnswer(a.raw)
+	}
+}
+
+// placedNodes names every node the seat mesh-placement places now, read from its state when a check composes (no
+// watch: a check reads it once). A state that cannot be read is an error, so the check says its composition was not
+// made rather than passing with no node asked (review finding 4).
+type placedNodes struct {
+	kv func(ctx context.Context) (jetstream.KeyValue, error)
+}
+
+func (p placedNodes) Placed() ([]string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), delivery.ComposeAnswerBound)
+	defer cancel()
+	kv, err := p.kv(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("the state %s cannot be read: %w", delivery.PlacementBucket, err)
+	}
+	lister, err := kv.ListKeys(ctx)
+	if errors.Is(err, jetstream.ErrNoKeysFound) {
+		return nil, nil // a placement that places nothing
+	}
+	if err != nil {
+		return nil, fmt.Errorf("the state %s cannot be listed: %w", delivery.PlacementBucket, err)
+	}
+	seen := map[string]bool{}
+	for key := range lister.Keys() {
+		if node, _, _, err := delivery.ParsePlacementKey(key); err == nil {
+			seen[node] = true
+		}
+	}
+	out := make([]string, 0, len(seen))
+	for n := range seen {
+		out = append(out, n)
+	}
+	sort.Strings(out)
+	return out, nil
+}
+
+// seatSandbox runs a compose job on the Go build seat's check stream, as the checker's own ask, and answers the
+// composer's verdict from the step's result (delivery.ComposeAnswer).
+type seatSandbox struct{ asker buildrun.Asker }
+
+func (s seatSandbox) Compose(ctx context.Context, job delivery.ComposeJob) (composer.Verdict, error) {
+	ask := delivery.StepAsk{ID: buildstep.NewID(), Kind: delivery.AskCheck, Language: delivery.AskGo, Asker: delivery.CheckerModule,
+		At: time.Now().UTC(), Compose: &job}
+	step, err := s.asker.Ask(ctx, ask)
+	if err != nil {
+		return composer.Verdict{}, err
+	}
+	if step.State != delivery.StepPassed {
+		return composer.Verdict{}, fmt.Errorf("the compose ask %s ended %s: %s", ask.ID, step.State, step.Reason)
+	}
+	var a delivery.ComposeAnswer
+	if err := json.Unmarshal(step.Result, &a); err != nil {
+		return composer.Verdict{}, fmt.Errorf("the compose ask %s answered no compose answer: %w", ask.ID, err)
+	}
+	var v composer.Verdict
+	if err := json.Unmarshal(a.Verdict, &v); err != nil || v.V != composer.Version {
+		return composer.Verdict{}, fmt.Errorf("the compose ask %s answered no composer verdict of version %d (%v)", ask.ID, composer.Version, err)
+	}
+	return v, nil
+}
+
+// manifestVerdicts are the indexer's refusals of the trunk's manifests, by module, from its modules' values
+// (delivery.Module.VerdictOf, ADR 0578 §3): what the sandbox's composer holds a refused module by.
+type manifestVerdicts struct {
+	mu sync.Mutex
+	by map[string]delivery.ManifestVerdict
+}
+
+func (m *manifestVerdicts) put(module string, v *delivery.ManifestVerdict) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.by == nil {
+		m.by = map[string]delivery.ManifestVerdict{}
+	}
+	if v == nil {
+		delete(m.by, module)
+		return
+	}
+	m.by[module] = *v
+}
+
+func (m *manifestVerdicts) all() map[string]delivery.ManifestVerdict {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	out := make(map[string]delivery.ManifestVerdict, len(m.by))
+	for k, v := range m.by {
+		out[k] = v
+	}
+	return out
+}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/integration_test.go

@@ -10,6 +10,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strings"
 	"sync"
@@ -21,10 +22,10 @@ import (
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
+	gobuild "git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/announce"
-	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/process"
 
 	"mesh-delivery-checker/internal/check"
@@ -87,7 +88,7 @@ type fakeBuildModules struct {
 	calls    map[string]int // by `<module>.<tool>`
 	testTool *testing.T
 	// beside is, by workspace, the siblings the fetch placed in it as `<owner/repo> <commit>`, sorted: a digest echoes them
-	// (1929/AC2; mesh-sdk buildstep.besideOf), or the level runs whole and keeps nothing.
+	// (1929/AC2; mesh-build-go buildstep.besideOf), or the level runs whole and keeps nothing.
 	beside map[string][]string
 	// names are the nodes' names the last check ask carried, for the names check (ADR 0567 §12).
 	names []string
@@ -155,11 +156,11 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, kept jetstream.Key
 		t.Fatal(err)
 	}
 	language := strings.TrimPrefix(module, "mesh-build-")
-	if err := buildstep.DeclareAskWorkers(f.ctx, f.js, language, 30*time.Second); err != nil {
+	if err := gobuild.DeclareAskWorkers(f.ctx, f.js, language, 30*time.Second); err != nil {
 		t.Fatal(err)
 	}
 	prefix := map[string]string{"mesh-build-go": "build_go_", "mesh-build-node": "build_node_"}[module]
-	call := func(name string) buildstep.StepFunc {
+	call := func(name string) gobuild.StepFunc {
 		return func(ctx context.Context, args map[string]any) (any, error) {
 			tool := prefix + name
 			f.mu.Lock()
@@ -168,7 +169,7 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, kept jetstream.Key
 			return f.result(t, tool, args), nil
 		}
 	}
-	steps := buildstep.AskSteps{Fetch: call("fetch"), Test: call("test"),
+	steps := gobuild.AskSteps{Fetch: call("fetch"), Test: call("test"),
 		Kept: func(ctx context.Context, level, digest string) (int, bool, error) {
 			key, err := delivery.KeptKey(level, digest)
 			if err != nil {
@@ -191,7 +192,7 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, kept jetstream.Key
 		raw, _ := value.(json.RawMessage)
 		return kv.Put(f.ctx, key, raw)
 	}
-	p := &buildstep.Puller{Source: &buildstep.JetStreamAsks{JS: f.js, Language: language}, Language: language, Node: "n1", Put: put,
+	p := &gobuild.Puller{Source: &gobuild.JetStreamAsks{JS: f.js, Language: language}, Language: language, Node: "n1", Put: put,
 		Capacity: func() int { return 2 }, PullWait: 200 * time.Millisecond,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if a.Check != nil {
@@ -199,7 +200,7 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, kept jetstream.Key
 				f.names = a.Check.NodeNames
 				f.mu.Unlock()
 			}
-			return buildstep.RunAsk(ctx, steps, a)
+			return gobuild.RunAsk(ctx, steps, a)
 		}}
 	go func() { _ = p.Pull(f.ctx) }()
 }
@@ -262,6 +263,58 @@ type bed struct {
 	mu       sync.Mutex
 }
 
+// engine places each node and serves compose-candidate for the first one, as its node-engine does on the bus (answered on
+// the seat verb's caller-named and plain subjects); the others never answer. It answers what it was asked.
+func (b *bed) engine(t *testing.T, nodes ...string) func() []delivery.ComposeCandidateAsk {
+	t.Helper()
+	kv, err := b.js.CreateKeyValue(b.ctx, jetstream.KeyValueConfig{Bucket: delivery.PlacementBucket, History: 1})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, n := range nodes {
+		pk, _ := delivery.PlacementNodeKey(n)
+		raw, _ := json.Marshal(delivery.Placement{Node: n})
+		if _, err := kv.Put(b.ctx, pk, raw); err != nil {
+			t.Fatal(err)
+		}
+	}
+	nc, err := nats.Connect(b.srvURL, nats.UserInfo("ctl", "pw"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(nc.Close)
+	var mu sync.Mutex
+	var asked []delivery.ComposeCandidateAsk
+	answer := func(m *nats.Msg) {
+		ask, err := delivery.DecodeComposeCandidateAsk(m.Data)
+		if err != nil {
+			_ = m.Respond([]byte(`{"error":"` + err.Error() + `"}`))
+			return
+		}
+		mu.Lock()
+		asked = append(asked, ask)
+		mu.Unlock()
+		a := delivery.ComposeCandidateAnswer{Node: nodes[0], Candidate: ask.Candidate, Verdict: delivery.ComposeCandidateComposed,
+			Own: delivery.ModuleComposed{Module: "node", State: delivery.ModuleComposedState, Digest: "sha256:" + strings.Repeat("b", 64)}}
+		raw, err := delivery.EncodeComposeCandidateAnswer(a)
+		if err != nil {
+			t.Error(err)
+		}
+		out, _ := json.Marshal(map[string]any{"result": json.RawMessage(raw), "node": nodes[0]})
+		_ = m.Respond(out)
+	}
+	for _, subject := range []string{"mesh.seat.node-engine.call.compose-candidate." + nodes[0] + ".>", "mesh.seat.node-engine.tool.compose-candidate." + nodes[0]} {
+		if _, err := nc.Subscribe(subject, answer); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return func() []delivery.ComposeCandidateAsk {
+		mu.Lock()
+		defer mu.Unlock()
+		return slices.Clone(asked)
+	}
+}
+
 // startBed starts the bus, the buckets the controller makes from the checker's and the other parts' manifests, the build
 // modules' streams and the checker's durable consumers on them, one node's toolchains, the gate's source naming the trunk, and
 // the fake build modules. It runs no checker.
@@ -509,14 +562,20 @@ func (b *bed) owed(t *testing.T, number int, head, state string) delivery.Owed {
 func TestCheckerJudgesACandidateAndOwesItsStatus(t *testing.T) { // N6/AC5, 1300/AC5, 1445/AC1, 1929/AC1
 	b := startBed(t)
 	key := b.candidate(t, "feat/x", pull(repo, 7, head1))
+	// ADR 0593 §7, §9 (D12): n1 and n2 are placed; n1's engine answers compose-candidate on the bus, n2's never does.
+	asked := b.engine(t, "n1", "n2")
 	b.start(t, nil)
 	v := b.verdict(t, key, ended)
 	if v.State != delivery.VerdictPass || v.Levels[delivery.LevelUnit].Run != 2 || v.Levels[delivery.LevelIntegration].Run != 2 || v.Trunk[repo] != trunk {
 		t.Fatalf("verdict = %+v", v)
 	}
-	if v.Composition == nil || v.Composition.State != delivery.CompositionNotRun || len(v.Machines) != 1 || v.Machines[0] != "n1" {
+	if c := v.Composition; c == nil || c.State != delivery.CompositionPass || !slices.Equal(c.Machines, []string{"n1"}) ||
+		!strings.Contains(c.Words, "n2: "+delivery.ComposeNoAnswer) || len(v.Machines) != 1 || v.Machines[0] != "n1" {
 		t.Errorf("composition %+v machines %v", v.Composition, v.Machines)
 	}
+	if got := asked(); len(got) == 0 || got[0].Candidate != key {
+		t.Errorf("n1's engine was asked %+v, want the check's candidate %s", got, key)
+	}
 	b.fake.mu.Lock()
 	names := b.fake.names
 	b.fake.mu.Unlock()

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/judge.go

@@ -11,8 +11,8 @@ import (
 
 	"github.com/nats-io/nats.go/jetstream"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/process"
 
 	"mesh-delivery-checker/internal/check"
@@ -26,10 +26,12 @@ type judgeDeps struct {
 	kept     check.KV
 	previews check.KV
 	repos    *repoModules
-	forge    check.Forge
-	announce check.Announcer
-	builds   check.BuildStates
-	// compositions is the assigner's bucket of compositions; nil leaves every composition not run.
+	// published is the indexer's packages state as it is followed (packages.go).
+	published *publishedPackages
+	forge     check.Forge
+	announce  check.Announcer
+	builds    check.BuildStates
+	// compositions makes a check's composition from the engines' answers (ADR 0593 §7); nil leaves it not run.
 	compositions check.CompositionReader
 	// nodes names every node with a record; nil hands no names.
 	nodes *nodeNames
@@ -95,7 +97,7 @@ func newJudge(d judgeDeps) check.Judge {
 		nodes = d.nodes
 	}
 	return &check.Examiner{Nodes: nodes, Compositions: d.compositions, Asks: d.asks, Toolchains: d.tools,
-		Kept: check.Kept{Store: d.kept}, Previews: d.previews, Modules: d.repos, Packages: d.repos, Published: d.repos, Forge: d.forge, Runs: d.repos, Builds: d.builds, Announce: d.announce, Trunks: d.trunks, Manifests: d.repos, Predefined: d.predefined, Logf: d.logf}
+		Kept: check.Kept{Store: d.kept}, Previews: d.previews, Modules: d.repos, Packages: d.repos, Published: d.published, Forge: d.forge, Runs: d.repos, Builds: d.builds, Announce: d.announce, Trunks: d.trunks, Manifests: d.repos, Predefined: d.predefined, Logf: d.logf}
 }
 
 // manifestKV reads a manifest by its digest.
@@ -109,6 +111,8 @@ type manifestKV interface {
 type repoModules struct {
 	manifests manifestKV
 	logf      func(format string, args ...any)
+	// verdicts keeps the indexer's verdict on each module's manifest, for the sandbox's composer (engines.go); nil keeps none.
+	verdicts *manifestVerdicts
 
 	mu     sync.Mutex
 	langs  map[string]map[string]bool     // by manifest digest: the languages of its artifacts
@@ -118,7 +122,6 @@ type repoModules struct {
 	repoOf map[string]string              // by module: its repository
 	commit map[string]string              // by module: the commit its record was computed at (the commit the mesh runs)
 	typed  map[string]string              // by module: its manifest digest
-	uses   map[string][]string            // by module: the mesh packages it uses (Inputs2.Packages, ADR 0573 §2)
 }
 
 // Put takes a change of the indexer's modules bucket in: a module's repository and the languages its manifest names.
@@ -127,15 +130,16 @@ func (r *repoModules) Put(ctx context.Context, key string, value []byte, deleted
 	if r.repoOf == nil {
 		r.repoOf, r.typed, r.langs, r.commit = map[string]string{}, map[string]string{}, map[string]map[string]bool{}, map[string]string{}
 		r.tsPkgs, r.path, r.named = map[string][]string{}, map[string]string{}, map[string]map[string][]string{}
-		r.uses = map[string][]string{}
 	}
 	if deleted {
+		if r.verdicts != nil {
+			r.verdicts.put(key, nil)
+		}
 		delete(r.repoOf, key)
 		delete(r.typed, key)
 		delete(r.commit, key)
 		delete(r.path, key)
 		delete(r.named, key)
-		delete(r.uses, key)
 		r.mu.Unlock()
 		return
 	}
@@ -144,16 +148,15 @@ func (r *repoModules) Put(ctx context.Context, key string, value []byte, deleted
 	if err != nil {
 		return
 	}
+	if r.verdicts != nil {
+		r.verdicts.put(key, m.VerdictOf(key))
+	}
 	r.mu.Lock()
 	r.repoOf[key] = m.Repository
 	r.typed[key] = m.Manifest
 	r.commit[key] = m.Commit
 	r.path[key] = m.Path
 	r.named[key] = m.ArtifactPaths
-	r.uses[key] = nil
-	if m.Inputs2 != nil {
-		r.uses[key] = m.Inputs2.Packages
-	}
 	_, known := r.langs[m.Manifest]
 	r.mu.Unlock()
 	if m.Manifest == "" || known {
@@ -185,28 +188,6 @@ func (r *repoModules) Put(ctx context.Context, key string, value []byte, deleted
 	r.mu.Unlock()
 }
 
-// LatestPackages is the latest published version of each mesh package a module of the mesh uses, and of mesh-sdk's Go
-// module always (novox/hq ADR 0573 §2): the trunk merge of the module whose directory holds it, as the indexer's modules
-// say. A package no module holds is left out: a check builds it at the version go.mod names.
-func (r *repoModules) LatestPackages() delivery.PackageVersions {
-	r.mu.Lock()
-	defer r.mu.Unlock()
-	used := map[string]bool{check.SDKModulePath: true}
-	held := map[string]delivery.Module{}
-	for module, repo := range r.repoOf {
-		for _, p := range r.uses[module] {
-			used[p] = true
-		}
-		held[module] = delivery.Module{Repository: repo, Path: r.path[module], Commit: r.commit[module]}
-	}
-	pkgs := make([]string, 0, len(used))
-	for p := range used {
-		pkgs = append(pkgs, p)
-	}
-	versions, _ := delivery.PackageVersionsOf(pkgs, held)
-	return versions
-}
-
 // PackagePaths are the paths, relative to the repository, that the TypeScript package artifacts of a repository's modules
 // are built from, sorted: the named paths the indexer keeps in each module's value (delivery.Module.ArtifactPaths; only the
 // indexer reads them from a manifest, the lead's decision L8), under the module's directory. None for a module whose value

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/judge_test.go

@@ -8,9 +8,10 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 type memManifests map[string][]byte
@@ -113,19 +114,33 @@ func TestTheTypeScriptPackagesPathsComeFromTheIndexersModulesNotTheManifest(t *t
 	if got := r.PackagePaths("novox/mesh-delivery"); len(got) != 0 {
 		t.Errorf("another repository: %v", got)
 	}
-	// Issue 1585 (ADR 0573 §2): the latest published version of mesh-sdk's Go module and of every package a module uses is
-	// the commit of the module that holds it; a package no module holds is left out.
-	put(".", nil)
-	const contract = "git.novox.be/novox/mesh-controller/modules/route-proxy/contract"
-	user, err := delivery.EncodeModule(delivery.Module{Repository: "novox/mesh-catalog", Commit: strings.Repeat("b", 40), FP: "src1:" + strings.Repeat("b", 64),
-		Manifest: delivery.ManifestDigest([]byte(sdkManifest)), Path: "modules/x",
-		Inputs2: &delivery.KeptInputs2{Tree: "t", Packages: []string{contract, "git.novox.be/novox/mesh-sdk/go"}}})
-	if err != nil {
-		t.Fatal(err)
+}
+
+// ADR 0593 §2 (D8): a Go check builds every mesh package at the version the indexer's packages state publishes, read
+// there and computed nowhere here: a key's module at its commit, a deleted key gone, an unreadable value left out.
+func TestThePublishedVersionsAreTheIndexersPackagesState(t *testing.T) {
+	var p publishedPackages
+	put := func(module, repository, dir, commit string) {
+		key, _ := delivery.PackagesKey(module)
+		raw, err := delivery.EncodePublishedPackages(delivery.PublishedPackages{Module: module, Repository: repository, Dir: dir,
+			Commit: commit, Requires: strings.Repeat("e", 64),
+			Packages: []delivery.PackageDigest{{Package: module, Digest: strings.Repeat("d", 64)}}, At: time.Now().UTC()})
+		if err != nil {
+			t.Fatal(err)
+		}
+		p.Put(key, raw, false)
 	}
-	r.Put(context.Background(), "x", user, false)
-	if got := r.LatestPackages(); !reflect.DeepEqual(got, delivery.PackageVersions{"git.novox.be/novox/mesh-sdk/go": strings.Repeat("a", 40)}) {
-		t.Errorf("latest packages = %v, want mesh-sdk at its module's commit and no unheld contract", got)
+	const sdk, build = "git.novox.be/novox/mesh-sdk/go", "git.novox.be/novox/mesh-catalog/modules/mesh-build-go"
+	put(sdk, "novox/mesh-sdk", "go", strings.Repeat("a", 40))
+	put(build, "novox/mesh-catalog", "modules/mesh-build-go", strings.Repeat("b", 40))
+	p.Put("broken", []byte("{"), false)
+	if got := p.LatestPackages(); !reflect.DeepEqual(got, delivery.PackageVersions{sdk: strings.Repeat("a", 40), build: strings.Repeat("b", 40)}) {
+		t.Errorf("latest packages = %v", got)
+	}
+	key, _ := delivery.PackagesKey(build)
+	p.Put(key, nil, true)
+	if got := p.LatestPackages(); len(got) != 1 || got[sdk] == "" {
+		t.Errorf("after a delete: %v", got)
 	}
 }
 

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go

@@ -20,9 +20,9 @@ import (
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/announce"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/process"
 
 	"mesh-delivery-checker/internal/check"
@@ -169,23 +169,19 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if kv := process.OptionalBucket(ctx, js, delivery.BuilderBuildsBucket, "the line says nothing of the builds until the checker starts again", logger.Printf); kv != nil {
 		builds = buildReader{kvStore{kv}}
 	}
-	// The assigner's compositions (ADR 0528 clause 5, issue 1297): their bucket is looked up at each check until it is
-	// there, so an assigner delivered after the checker started is read at the next check, and followed from then on.
-	compositions := &lazyCompositions{open: func(at context.Context) (check.CompositionReader, error) {
-		kv, err := js.KeyValue(at, delivery.AssignerCompositionsBucket)
-		if err != nil {
-			return nil, err
-		}
-		cw := compositionWatch{kv: kv}
-		if pkv, err := js.KeyValue(at, delivery.PresenceBucket); err == nil {
-			cw.presence = pkv
-		}
-		if err := followCompositions(ctx, kv, ch); err != nil {
-			return nil, fmt.Errorf("the bucket %s cannot be watched: %w", delivery.AssignerCompositionsBucket, err)
-		}
-		logger.Printf("the assigner's compositions are read from %s", delivery.AssignerCompositionsBucket)
-		return cw, nil
-	}}
+	// The check's composition is the checker's, from what each placed node's engine answers (ADR 0593 §7, §9).
+	answerBound, err := composeAnswerBound(getenv("MESH_CHECKER_SETTINGS"))
+	if err != nil {
+		return err
+	}
+	verdicts := &manifestVerdicts{}
+	compositions := check.EngineCompositions{
+		Asker:    engineAsks{call: caller.CallOn},
+		Placed:   placedNodes{kv: func(at context.Context) (jetstream.KeyValue, error) { return js.KeyValue(at, delivery.PlacementBucket) }}.Placed,
+		Bound:    answerBound,
+		Sandbox:  seatSandbox{asker: buildrun.Asker{Publisher: asks, Waiter: waiter, Bound: stepBound}},
+		Verdicts: verdicts.all,
+	}
 	// The tries (ADR 0501 §5) are judged by the same judge, held by the same deliveries.
 	tryer := &check.Tryer{Tries: kvStore{buckets[check.TriesBucket]}, Bound: checkBound, NotTaken: stepBound, Logf: logger.Printf}
 	announce := func(ctx context.Context, event, key string) {
@@ -194,12 +190,28 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 			logger.Printf("%s of %s was written and the part that reads it could not be told: %v", event, key, err)
 		}
 	}
-	repos := &repoModules{manifests: kvStore{buckets[delivery.ManifestsBucket]}, logf: logger.Printf}
+	repos := &repoModules{manifests: kvStore{buckets[delivery.ManifestsBucket]}, logf: logger.Printf, verdicts: verdicts}
+	compositions.Composer = func() string { return repos.CommitOf(check.NodeEngineModule) }
+	compositions.Manifests = repos
+	// The indexer's packages state (ADR 0593 §2): followed once the bus has it, so a Go check builds every mesh package at
+	// its published version; until then a check builds each at the version its go.mod names.
+	published := &publishedPackages{}
+	process.AwaitBucket(ctx, js, conn, delivery.PackagesBucket, "a Go check builds each mesh package at the version its go.mod names",
+		logger.Printf).Ready(func(kv jetstream.KeyValue) {
+		w, err := settle(ctx, kv, func(e jetstream.KeyValueEntry) { published.Put(e.Key(), e.Value(), !opOf(e)) })
+		if err != nil {
+			logger.Printf("%s cannot be watched, so a Go check builds each mesh package at the version its go.mod names: %v", delivery.PackagesBucket, err)
+			return
+		}
+		go func() {
+			_ = follow(ctx, w, func(e jetstream.KeyValueEntry) { published.Put(e.Key(), e.Value(), !opOf(e)) })
+		}()
+	})
 	ch.Runs = repos // the node-engine a check reads beside at its running commit (ADR 0548 §6)
 	ch.Judge = newJudge(judgeDeps{
 		asks: buildrun.Asker{Publisher: asks, Waiter: waiter, Bound: stepBound}, tools: tools, trunks: trunks,
 		kept: kvStore{buckets[delivery.CheckerKeptBucket]}, previews: kvStore{buckets[delivery.PreviewsBucket]},
-		repos: repos, builds: builds, forge: forgeReads{call: caller.Call}, logf: logger.Printf,
+		repos: repos, published: published, builds: builds, forge: forgeReads{call: caller.Call}, logf: logger.Printf,
 		announce: announce, compositions: compositions,
 		nodes: openNodeNames(ctx, js, logger.Printf),
 		predefined: keptPredefined{process.AwaitBucket(ctx, js, conn, delivery.IndexerModule+"_"+delivery.IndexerPredefinedState,

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/packages.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"sync"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// publishedPackages is the indexer's state `packages` as the checker follows it (novox/hq ADR 0593 §2): by mesh Go
+// module, the latest published commit of its repository the indexer read its packages at. The indexer alone computes a
+// package's version; the checker reads it, so a Go check builds every mesh package at the version the mesh publishes
+// (check.Examiner.Published) and computes none.
+type publishedPackages struct {
+	mu     sync.Mutex
+	byKey  map[string]delivery.PublishedPackages
+	unread map[string]string
+}
+
+// Put takes one key of the state in: its value, or its deletion. A value that does not decode is kept out and remembered
+// with why, never read as an older one.
+func (p *publishedPackages) Put(key string, raw []byte, deleted bool) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.byKey == nil {
+		p.byKey, p.unread = map[string]delivery.PublishedPackages{}, map[string]string{}
+	}
+	delete(p.byKey, key)
+	delete(p.unread, key)
+	if deleted {
+		return
+	}
+	v, err := delivery.DecodePublishedPackages(raw)
+	if err != nil {
+		p.unread[key] = err.Error()
+		return
+	}
+	p.byKey[key] = v
+}
+
+// LatestPackages is the latest published version of every mesh Go module the indexer holds, by module path: the commit
+// its repository was published at. A module the state does not hold is left out: a check builds it at the version
+// go.mod names.
+func (p *publishedPackages) LatestPackages() delivery.PackageVersions {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	out := delivery.PackageVersions{}
+	for _, v := range p.byKey {
+		if v.Module != "" && v.Commit != "" {
+			out[v.Module] = v.Commit
+		}
+	}
+	return out
+}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/refused_test.go

@@ -12,7 +12,7 @@ import (
 
 	"github.com/nats-io/nats.go/jetstream"
 
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 )
 
 // 1945 (a part exits at start for a bucket it works without): a bus that refuses every toolchains bucket leaves the

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/settings.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// The checker's own settings (its config, written by the node-engine into ${dir:state}/settings.json, named to the
+// process by MESH_CHECKER_SETTINGS): compose-answer-bound, the seconds a check waits for a node's engine to answer
+// compose-candidate (novox/hq ADR 0593 §7, §9: 60 by default; the checker owns it).
+
+// composeAnswerBound reads compose-answer-bound from the settings file at path: delivery.ComposeAnswerBound where no
+// file or no value is there; a value that is no number of seconds from 1 to 600 is refused, naming it.
+func composeAnswerBound(path string) (time.Duration, error) {
+	if path == "" {
+		return delivery.ComposeAnswerBound, nil
+	}
+	raw, err := os.ReadFile(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return delivery.ComposeAnswerBound, nil
+	}
+	if err != nil {
+		return 0, err
+	}
+	var s struct {
+		Bound *float64 `json:"compose-answer-bound"`
+	}
+	if err := json.Unmarshal(raw, &s); err != nil {
+		return 0, fmt.Errorf("%s is no settings file: %w", path, err)
+	}
+	if s.Bound == nil {
+		return delivery.ComposeAnswerBound, nil
+	}
+	if *s.Bound < 1 || *s.Bound > 600 || *s.Bound != float64(int(*s.Bound)) {
+		return 0, fmt.Errorf("compose-answer-bound is %v: a whole number of seconds from 1 to 600", *s.Bound)
+	}
+	return time.Duration(*s.Bound) * time.Second, nil
+}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/settings_test.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// ADR 0593 §7: the answer bound is the checker's setting compose-answer-bound, 60 s when the file or the value is
+// absent; a value that is no whole number of seconds from 1 to 600 stops the start, naming it.
+func TestTheAnswerBoundIsTheCheckersSetting(t *testing.T) {
+	dir := t.TempDir()
+	for _, row := range []struct {
+		body string
+		want time.Duration
+		err  bool
+	}{{"", delivery.ComposeAnswerBound, false}, {`{}`, delivery.ComposeAnswerBound, false},
+		{`{"compose-answer-bound": 90}`, 90 * time.Second, false}, {`{"compose-answer-bound": 0}`, 0, true},
+		{`{"compose-answer-bound": 1.5}`, 0, true}} {
+		path := filepath.Join(dir, "settings.json")
+		os.Remove(path)
+		if row.body != "" {
+			if err := os.WriteFile(path, []byte(row.body), 0o600); err != nil {
+				t.Fatal(err)
+			}
+		}
+		got, err := composeAnswerBound(path)
+		if (err != nil) != row.err || got != row.want {
+			t.Errorf("%q: %s, %v", row.body, got, err)
+		}
+	}
+}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/toolchains.go

@@ -14,7 +14,7 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 )
 
 // toolchainStreams are the stream each build module carries its toolchain.reported event on, as the bus names it

modules/mesh-delivery-checker/files/settings.json

@@ -0,0 +1,3 @@
+{
+  "compose-answer-bound": 60
+}

modules/mesh-delivery-checker/go.mod

@@ -3,12 +3,15 @@ module mesh-delivery-checker
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102153155-43788bbfdef3
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )
 
+require git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9
+
 require (
+	git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun v0.0.0-00010101000000-000000000000
 	github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op // indirect
 	github.com/google/go-tpm v0.9.8 // indirect
 	github.com/klauspost/compress v1.20.0 // indirect
@@ -20,3 +23,5 @@ require (
 	golang.org/x/sys v0.48.0 // indirect
 	golang.org/x/time v0.15.0 // indirect
 )
+
+replace git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun => ../mesh-delivery-builder/buildrun

modules/mesh-delivery-checker/go.sum

@@ -1,5 +1,7 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102153155-43788bbfdef3 h1:K3Uw1b+IPAKd8NeGzJNqggQifnEYYv9IUxBFpunx05c=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102153155-43788bbfdef3/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9 h1:DrwGUXwv3A4KTiUjepbZMNumoillbMfYrKBEl9EZiOc=
+git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep v0.0.0-20261102191416-68e7a2ddbfb9/go.mod h1:kpsX4Pgss5EeuBvel1zWa2ogj7MkR3jZso6oa/J0YUQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128 h1:aI1DhZAuqVBXbybSqhLNOGX5rUOrn9T0cHNCDUQF7IQ=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261102191058-f02f142af128/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=

modules/mesh-delivery-checker/internal/check/awaiting.go

@@ -1,168 +0,0 @@
-package check
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"strings"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-// ErrAssignerNotRunning is what a wait for a composition answers when no instance of the assigner is online: nobody is
-// making it, so the check does not wait for it (issue 1297). The verdict says the composition is not judged, and when the
-// assigner starts and writes it, the checker takes it in then (Checker.Composed).
-var ErrAssignerNotRunning = errors.New(delivery.AssignerNotRunning)
-
-// PresenceEvent is a change of the watchman's presence bucket, or Settled once what stands was handed.
-type PresenceEvent struct {
-	Key     string
-	Online  bool
-	Settled bool
-}
-
-// CompositionEvent is a change of the composition's key (its value, nil for a delete), or Settled once what stands was
-// handed.
-type CompositionEvent struct {
-	Value   []byte
-	Settled bool
-}
-
-// AwaitComposition answers the assigner's composition once one is written that does not wait, while an instance of the
-// assigner is online by the watchman's presence (`part.mesh-delivery-assigner.<instance>`). Once both watches handed
-// what stands, no instance online is ErrAssignerNotRunning at once, and so is the last instance going offline during the
-// wait. No timer: every answer follows an event; ctx ending is ctx's error.
-func AwaitComposition(ctx context.Context, presence <-chan PresenceEvent, comps <-chan CompositionEvent) (delivery.CompositionVerdict, error) {
-	online := map[string]bool{}
-	presenceSettled, compSettled := false, false
-	for {
-		select {
-		case <-ctx.Done():
-			return delivery.CompositionVerdict{}, ctx.Err()
-		case e, ok := <-presence:
-			if !ok {
-				return delivery.CompositionVerdict{}, errors.New("the watch of the assigner's presence ended")
-			}
-			if e.Settled {
-				presenceSettled = true
-				break
-			}
-			if _, part, instance, err := delivery.ParsePresenceKey(e.Key); err == nil && part == delivery.AssignerModule {
-				if e.Online {
-					online[instance] = true
-				} else {
-					delete(online, instance)
-				}
-			}
-		case e, ok := <-comps:
-			if !ok {
-				return delivery.CompositionVerdict{}, errors.New("the watch of the composition ended")
-			}
-			if e.Settled {
-				compSettled = true
-				break
-			}
-			if e.Value == nil {
-				break
-			}
-			v, err := delivery.DecodeCompositionVerdict(e.Value)
-			if err != nil {
-				return delivery.CompositionVerdict{}, fmt.Errorf("the composition cannot be read: %w", err)
-			}
-			if v.State != delivery.CompositionWaits {
-				return v, nil
-			}
-		}
-		if presenceSettled && compSettled && len(online) == 0 {
-			return delivery.CompositionVerdict{}, ErrAssignerNotRunning
-		}
-	}
-}
-
-// withComposition is v with the assigner's composition taken in: a failed one fails the check, naming its machine.
-func withComposition(v *delivery.Verdict, comp delivery.CompositionVerdict) {
-	v.Composition = comp.Composition()
-	v.Took.Composition = comp.Took
-	if comp.State == delivery.CompositionFail {
-		machine := comp.Machine
-		if machine == "" {
-			machine = "the composition"
-		}
-		f := delivery.FailedFirst{Machine: machine, Words: comp.Words}
-		if v.State == delivery.VerdictFail {
-			addFailure(v, f) // the tests failed too: the composition is named after them (the operator, 2026-11-02)
-			return
-		}
-		v.State, v.Failed = delivery.VerdictFail, f
-	}
-}
-
-// notJudged says whether a verdict's composition was not judged because the assigner was not running.
-func notJudged(v delivery.Verdict) bool {
-	return v.Composition != nil && v.Composition.State == delivery.CompositionNotRun && v.Composition.Words == delivery.AssignerNotRunning
-}
-
-// unanswered says whether a verdict failed only on its composition, and that only because nodes the change places did
-// not answer its placement in time (delivery.CompositionUnanswered, ADR 0559 §5): its tests passed (the composition is
-// its first failure, and a composition is named after every other failure), so a later composition of the same heads is
-// taken in on its event, with no new check (ADR 0548 §1: a part of the mesh not heard is judged again when it is heard).
-func unanswered(v delivery.Verdict) bool {
-	return v.State == delivery.VerdictFail && v.Composition != nil && v.Composition.State == delivery.CompositionFail &&
-		strings.Contains(v.Composition.Words, delivery.CompositionUnanswered) && v.Failed.Words == v.Composition.Words
-}
-
-// Composed takes in a composition the assigner wrote after the check's verdict said it was not judged because the
-// assigner was not running (the assigner started since), or after it failed only because placed nodes had not answered
-// (unanswered): the verdict and its status are written again with it. A composition of heads no candidate holds now, or
-// of a verdict that judged its composition otherwise, is left.
-func (ch *Checker) Composed(ctx context.Context, comp delivery.CompositionVerdict) {
-	ch.init()
-	if comp.State == delivery.CompositionWaits {
-		return
-	}
-	ckey, err := delivery.CandidatesKey(comp.Group)
-	if err != nil {
-		return
-	}
-	ch.mu.Lock()
-	c, ok := ch.known[ckey]
-	ch.mu.Unlock()
-	if !ok {
-		return
-	}
-	cs := CaseOf(c, ch.heads())
-	if cs == nil || cs.HeadsHash != comp.Heads {
-		return
-	}
-	cur, rev, found, err := ch.Verdicts.Get(ctx, cs.Key)
-	if err != nil || !found {
-		return
-	}
-	v, err := delivery.DecodeVerdict(cur)
-	if err != nil {
-		return
-	}
-	switch {
-	case v.State == delivery.VerdictPass && notJudged(v):
-	case unanswered(v) && comp.Words != v.Composition.Words:
-		// The nodes answered since (or another failure stands now): the verdict is its tests' pass with this composition.
-		v.State, v.Failed, v.Failures = delivery.VerdictPass, delivery.FailedFirst{}, nil
-	default:
-		return
-	}
-	withComposition(&v, comp)
-	if v.Composition != nil && v.Composition.State != delivery.CompositionNotRun {
-		v.Composition.FPSet = cs.FPSet
-	}
-	data, err := delivery.EncodeVerdict(v)
-	if err != nil {
-		ch.logf("%s: the verdict with its composition cannot be written: %v", cs.Key, err)
-		return
-	}
-	if _, err := ch.Verdicts.Update(ctx, cs.Key, data, rev); err != nil {
-		ch.logf("%s: the verdict with its composition could not be written: %v", cs.Key, err)
-		return
-	}
-	ch.writeOwed(ctx, cs, v, Outcome{Verdict: v})
-	ch.logf("%s: the composition came after the verdict: %s", cs.Key, comp.State)
-}

modules/mesh-delivery-checker/internal/check/awaiting_test.go

@@ -1,170 +0,0 @@
-package check
-
-import (
-	"context"
-	"errors"
-	"strings"
-	"testing"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/delivery"
-)
-
-func assignerOn(instance string, online bool) PresenceEvent {
-	key, _ := delivery.PresencePartKey(delivery.AssignerModule, instance)
-	return PresenceEvent{Key: key, Online: online}
-}
-
-func compEvent(t *testing.T, v delivery.CompositionVerdict) CompositionEvent {
-	t.Helper()
-	data, err := delivery.EncodeCompositionVerdict(v)
-	if err != nil {
-		t.Fatal(err)
-	}
-	return CompositionEvent{Value: data}
-}
-
-var passed = delivery.CompositionVerdict{Group: "feat/x", Heads: "0123456789ab", State: delivery.CompositionPass, SDK: "x", Machines: []string{"g14"}}
-
-// 1297/B3d: with no assigner online, the wait answers ErrAssignerNotRunning as soon as both watches handed what stands.
-func TestNoAssignerAnswersAtOnce(t *testing.T) {
-	presence, comps := make(chan PresenceEvent, 4), make(chan CompositionEvent, 4)
-	presence <- assignerOn("novox", false)
-	presence <- PresenceEvent{Settled: true}
-	comps <- CompositionEvent{Settled: true}
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-	defer cancel()
-	if _, err := AwaitComposition(ctx, presence, comps); !errors.Is(err, ErrAssignerNotRunning) {
-		t.Fatalf("answered %v, want the assigner not running", err)
-	}
-}
-
-// 1297/B3d: with the assigner online it waits for the key, past a composition that waits, and answers the verdict.
-func TestAnOnlineAssignerIsWaitedFor(t *testing.T) {
-	presence, comps := make(chan PresenceEvent, 4), make(chan CompositionEvent, 4)
-	presence <- assignerOn("novox", true)
-	presence <- PresenceEvent{Settled: true}
-	comps <- CompositionEvent{Settled: true}
-	done := make(chan error, 1)
-	var got delivery.CompositionVerdict
-	go func() {
-		var err error
-		got, err = AwaitComposition(context.Background(), presence, comps)
-		done <- err
-	}()
-	comps <- compEvent(t, delivery.CompositionVerdict{Group: "feat/x", Heads: "0123456789ab", State: delivery.CompositionWaits, Words: "w"})
-	select {
-	case err := <-done:
-		t.Fatalf("answered before the composition was written: %v", err)
-	case <-time.After(50 * time.Millisecond):
-	}
-	comps <- compEvent(t, passed)
-	if err := <-done; err != nil || got.State != delivery.CompositionPass {
-		t.Fatalf("answered %+v, %v", got, err)
-	}
-	// And the last instance going offline during a wait ends it as not running.
-	presence2, comps2 := make(chan PresenceEvent, 4), make(chan CompositionEvent, 4)
-	presence2 <- assignerOn("novox", true)
-	presence2 <- PresenceEvent{Settled: true}
-	comps2 <- CompositionEvent{Settled: true}
-	presence2 <- assignerOn("novox", false)
-	if _, err := AwaitComposition(context.Background(), presence2, comps2); !errors.Is(err, ErrAssignerNotRunning) {
-		t.Errorf("the assigner going offline answered %v", err)
-	}
-}
-
-// 1297/B3d: a passing check with no assigner says at once, loud, that its composition is not judged; never a pass of it.
-func TestAPassingCheckWithNoAssignerSaysTheCompositionIsNotJudged(t *testing.T) {
-	b := newBench(t)
-	b.ex.Compositions = &fakeCompositions{err: ErrAssignerNotRunning}
-	v := b.judge(t, caseOf(t, pullOf(repoA, 7, head1))).Verdict
-	if v.Composition == nil || v.Composition.State != delivery.CompositionNotRun || v.Composition.Words != delivery.AssignerNotRunning {
-		t.Fatalf("composition = %+v", v.Composition)
-	}
-	if words := compositionWords(v.Composition, 0); words != "composition not judged: the assigner is not running" {
-		t.Errorf("the line says %q", words)
-	}
-}
-
-// 1297/B3d: the assigner starting writes the composition later, and the checker takes it into the verdict that said it
-// was not judged, writing the status again; a failed one fails the check.
-func TestTheAssignerStartingBringsTheComposition(t *testing.T) {
-	for _, comp := range []delivery.CompositionVerdict{passed,
-		{Group: "feat/x", Heads: "", State: delivery.CompositionFail, SDK: "x", Machine: "g14", Words: "g14 runs web, which the change removes"}} {
-		ch, cs := checkerWithNotJudged(t)
-		comp.Heads = cs.HeadsHash
-		ch.Composed(context.Background(), comp)
-		raw, _, _, _ := ch.Verdicts.Get(context.Background(), cs.Key)
-		v, err := delivery.DecodeVerdict(raw)
-		if err != nil || v.Composition == nil || v.Composition.State != comp.State {
-			t.Fatalf("after the composition came, the verdict is %+v, %v", v, err)
-		}
-		if comp.State == delivery.CompositionFail && (v.State != delivery.VerdictFail || v.Failed.Machine != "g14") {
-			t.Errorf("a failed composition left the verdict %+v", v)
-		}
-		owed := ch.Owed.(*memKV)
-		keys, _ := owed.Keys(context.Background())
-		if len(keys) == 0 {
-			t.Fatal("no status was written again")
-		}
-		data, _, _, _ := owed.Get(context.Background(), keys[0])
-		o, _ := delivery.DecodeCheckerOwed(data)
-		if !strings.Contains(o.Text, "composition passed") && !strings.Contains(o.Text, "g14 runs web") {
-			t.Errorf("the status's line says %q", o.Text)
-		}
-	}
-
-	// ADR 0559 §5: a verdict that failed only because a placed node had not answered takes the same heads' later
-	// composition in on its event, a pass making it pass with no new check; a composition failing the same way is left.
-	ch, cs := checkerWithNotJudged(t)
-	silent := delivery.CompositionVerdict{Group: cs.Group, Heads: cs.HeadsHash, State: delivery.CompositionFail, SDK: "x", Machine: "g14",
-		Words: "g14 (offline) " + delivery.CompositionUnanswered}
-	ch.Composed(context.Background(), silent)
-	for _, row := range []struct {
-		name  string
-		comp  delivery.CompositionVerdict
-		state string
-	}{
-		{"the same failure again", silent, delivery.VerdictFail},
-		{"the node's answer", delivery.CompositionVerdict{Group: cs.Group, Heads: cs.HeadsHash, State: delivery.CompositionPass, SDK: "x"}, delivery.VerdictPass},
-	} {
-		ch.Composed(context.Background(), row.comp)
-		raw, _, _, _ := ch.Verdicts.Get(context.Background(), cs.Key)
-		if v, err := delivery.DecodeVerdict(raw); err != nil || v.State != row.state || v.Composition == nil || v.Composition.State != row.comp.State {
-			t.Errorf("%s: the verdict is %+v, %v", row.name, v, err)
-		}
-	}
-}
-
-// checkerWithNotJudged is a checker holding a candidate whose passing verdict said its composition was not judged.
-func checkerWithNotJudged(t *testing.T) (*Checker, *Case) {
-	t.Helper()
-	cs := caseOf(t, pullOf(repoA, 7, head1))
-	raw := candidateOf(t, cs.Group, pullOf(repoA, 7, head1))
-	ch := &Checker{Verdicts: newMemKV(), Owed: newMemKV(), Trunks: fixedTrunks{cs.Trunk}}
-	ckey, _ := delivery.CandidatesKey(cs.Group)
-	ch.init()
-	c, err := delivery.DecodeCandidate(raw)
-	if err != nil {
-		t.Fatal(err)
-	}
-	ch.known[ckey] = c
-	if got := CaseOf(c, ch.heads()); got == nil || got.Key != cs.Key {
-		t.Fatalf("the case is %+v, want %s", got, cs.Key)
-	}
-	v := delivery.Verdict{Group: cs.Group, Heads: cs.Heads, State: delivery.VerdictPass,
-		Levels:      map[string]delivery.LevelResult{delivery.LevelUnit: {Run: 1}, delivery.LevelIntegration: {Run: 1}},
-		Composition: &delivery.Composition{State: delivery.CompositionNotRun, Words: delivery.AssignerNotRunning}}
-	data, err := delivery.EncodeVerdict(v)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if _, err := ch.Verdicts.Create(context.Background(), cs.Key, data); err != nil {
-		t.Fatal(err)
-	}
-	return ch, cs
-}
-
-type fixedTrunks struct{ heads map[string]string }
-
-func (f fixedTrunks) Heads() map[string]string { return f.heads }

modules/mesh-delivery-checker/internal/check/beside.go

@@ -27,15 +27,14 @@ const (
 	catalogueRepository = "novox/mesh-catalog"
 	nodeEngineRepo      = "novox/mesh-host"
 	nodeEngineModule    = "mesh-host"
-	controllerRepo      = "novox/mesh-controller"
 )
 
 // besideRules are the repositories each core repository's tests read, as the tests state it (mesh-sdk go/internal/beside
 // beside.go): the catalogue, the node-engine, the SDK, and the delivery's pinned forge dependencies (mesh-catalog
 // checks/deps). Which commit of each is besideCommit's rule. No repository's tests read the controller, which ended by its
-// unassignment (novox/hq ADR 0590, issue 1126); its own repository keeps its siblings while it holds a module.
+// unassignment (novox/hq ADR 0590, issue 1126), and its repository is emptied and archived (ADR 0593 §11), so it has no
+// siblings placed either.
 var besideRules = map[string][]string{
-	controllerRepo:        {catalogueRepository, nodeEngineRepo, SDKRepository},
 	nodeEngineRepo:        {catalogueRepository, SDKRepository},
 	SDKRepository:         {catalogueRepository, nodeEngineRepo},
 	catalogueRepository:   {SDKRepository},

modules/mesh-delivery-checker/internal/check/composition.go

@@ -0,0 +1,28 @@
+package check
+
+import (
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// withComposition is v with the check's composition taken in: a failed one fails the check, naming its machine.
+func withComposition(v *delivery.Verdict, comp delivery.CompositionVerdict) {
+	v.Composition = comp.Composition()
+	v.Took.Composition = comp.Took
+	if comp.State == delivery.CompositionPass && len(comp.Warnings) > 0 && v.Composition != nil {
+		v.Composition.Words = strings.Join(comp.Warnings, "; ") // passed with a warning (ADR 0593 §9)
+	}
+	if comp.State == delivery.CompositionFail {
+		machine := comp.Machine
+		if machine == "" {
+			machine = "the composition"
+		}
+		f := delivery.FailedFirst{Machine: machine, Words: comp.Words}
+		if v.State == delivery.VerdictFail {
+			addFailure(v, f) // the tests failed too: the composition is named after them (the operator, 2026-11-02)
+			return
+		}
+		v.State, v.Failed = delivery.VerdictFail, f
+	}
+}

modules/mesh-delivery-checker/internal/check/composition_test.go

@@ -9,18 +9,17 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 )
 
-// fakeCompositions answers the assigner's composition of a check from memory, recording the keys asked.
+// fakeCompositions answers a check's composition from memory, recording the keys asked.
 type fakeCompositions struct {
 	v     delivery.CompositionVerdict
 	err   error
 	asked []string
-	// waits answers only that the composition waits, as the assigner does for a member the indexer holds no manifest of:
-	// Await returns only when its context ends.
+	// waits answers only when its context ends.
 	waits bool
 }
 
-func (f *fakeCompositions) Await(ctx context.Context, key string) (delivery.CompositionVerdict, error) {
-	f.asked = append(f.asked, key)
+func (f *fakeCompositions) Compose(ctx context.Context, c *Case) (delivery.CompositionVerdict, error) {
+	f.asked = append(f.asked, c.Key)
 	if f.waits {
 		<-ctx.Done()
 		return delivery.CompositionVerdict{}, ctx.Err()
@@ -95,3 +94,8 @@ func TestACompositionNotHadIsNotRun(t *testing.T) {
 		t.Errorf("a try asked for a composition: %v", f2.asked)
 	}
 }
+
+// fixedTrunks are trunk heads that never move.
+type fixedTrunks struct{ heads map[string]string }
+
+func (f fixedTrunks) Heads() map[string]string { return f.heads }

modules/mesh-delivery-checker/internal/check/engines.go

@@ -0,0 +1,238 @@
+package check
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/composer"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **A check's composition is the checker's, made from what each node's engine answers** (novox/hq ADR 0593 §7, §9).
+// Only a node knows whether a change composes there: the checker asks every placed node's engine
+// `node-engine.compose-candidate` in parallel, with the check's candidate, and waits at most its answer bound
+// (compose-answer-bound, 60 s by default). A node that refuses fails the check, naming the node and each module with the
+// engine's words; a node that does not answer within the bound, answers unready or cannot be asked is named, "not composed
+// on that node: no answer", and the check passes with that warning: its own composition judges again when it applies,
+// and the canary rule holds. The checker decides by the answer's verdict, never by its words.
+//
+// **A group that changes the node-engine's composition code** (a member of the node-engine's repository) is not judged by
+// the running engines, which cannot judge their own next code: each node's engine answers the composition input it
+// composed from (ComposeCandidateAsk.Input), and the composer program built from that member's head composes it in a
+// build module's sandbox (Sandbox), with every manifest of the catalogue as the case leaves it and the indexer's verdicts.
+
+// EngineAsker asks one node's engine to compose a check's candidate (the verb node-engine.compose-candidate on that node).
+type EngineAsker interface {
+	ComposeCandidate(ctx context.Context, node string, ask delivery.ComposeCandidateAsk) (delivery.ComposeCandidateAnswer, error)
+}
+
+// Sandbox runs a compose job on the Go build seat and answers the composer's verdict.
+type Sandbox interface {
+	Compose(ctx context.Context, job delivery.ComposeJob) (composer.Verdict, error)
+}
+
+// EngineCompositions is the checker's composition of a check (Examiner.Compositions).
+type EngineCompositions struct {
+	Asker EngineAsker
+	// Placed names every node in placement now (the seat mesh-placement's state), or why it cannot be read: then no node
+	// can be asked, and the composition is not made (an error), never passed with nobody asked.
+	Placed func() ([]string, error)
+	// Bound is the answer bound (the setting compose-answer-bound); zero is delivery.ComposeAnswerBound.
+	Bound time.Duration
+	// Composer is the commit of the node-engine the mesh runs, named as what composed (ADR 0548 §6's running commit).
+	Composer func() string
+	// Sandbox runs the composer of a node-engine member's head; nil leaves such a group judged by the running engines,
+	// said in a warning.
+	Sandbox Sandbox
+	// Manifests are the indexer's trunk manifest digests by module, and Verdicts its refusals of them: the catalogue the
+	// sandbox composes with, before the case's own manifests are laid over.
+	Manifests TrunkManifests
+	Verdicts  func() map[string]delivery.ManifestVerdict
+}
+
+// composerHead is the node-engine member's head of a case, or empty.
+func composerHead(c *Case) string {
+	if m := c.member(nodeEngineRepo); m != nil {
+		return m.Head
+	}
+	return ""
+}
+
+// Compose asks every placed node and judges their answers (JudgeEngines). An error is only a case it cannot ask at all.
+func (e EngineCompositions) Compose(ctx context.Context, c *Case) (delivery.CompositionVerdict, error) {
+	began := time.Now()
+	key, err := delivery.CompositionKey(c.Group, c.HeadsHash)
+	if err != nil {
+		return delivery.CompositionVerdict{}, err
+	}
+	var nodes []string
+	if e.Placed != nil {
+		if nodes, err = e.Placed(); err != nil {
+			return delivery.CompositionVerdict{}, fmt.Errorf("the placement cannot be read, so no node can be asked: %w", err)
+		}
+	}
+	bound := e.Bound
+	if bound <= 0 {
+		bound = delivery.ComposeAnswerBound
+	}
+	head := composerHead(c)
+	sandboxed := head != "" && e.Sandbox != nil
+	answers := map[string]delivery.ComposeCandidateAnswer{}
+	silent := map[string]string{}
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+	for _, node := range nodes {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			at, cancel := context.WithTimeout(ctx, bound)
+			defer cancel()
+			a, err := e.Asker.ComposeCandidate(at, node, delivery.ComposeCandidateAsk{Candidate: key, Input: sandboxed})
+			if err == nil && sandboxed && a.Verdict != delivery.ComposeCandidateUnready {
+				// The composer's build and run are the check's to bound, not the engine's answer bound. A composer that
+				// cannot run is no silent node (ADR 0593 §9 lets only that pass): the node's composition fails, naming
+				// the head.
+				if composed, serr := e.inSandbox(ctx, c, head, node, a); serr != nil {
+					a = delivery.ComposeCandidateAnswer{V: a.V, Node: node, Candidate: a.Candidate, Verdict: delivery.ComposeCandidateRefused,
+						Refused: "the composer at the node-engine's head " + head + " could not compose it: " + serr.Error()}
+				} else {
+					a = composed
+				}
+			}
+			mu.Lock()
+			defer mu.Unlock()
+			switch {
+			case err != nil:
+				silent[node] = err.Error()
+			case a.Verdict == delivery.ComposeCandidateUnready:
+				silent[node] = "unready"
+			default:
+				answers[node] = a
+			}
+		}()
+	}
+	wg.Wait()
+	// What composed, named by the node-engine's commit: the member's head in the sandbox, else the one the mesh runs.
+	composerName := "node-engine"
+	if sandboxed {
+		composerName = head
+	} else if e.Composer != nil && e.Composer() != "" {
+		composerName = e.Composer()
+	}
+	v := JudgeEngines(c.Group, c.HeadsHash, composerName, nodes, answers, silent)
+	if head != "" && e.Sandbox == nil {
+		v.Warnings = append(v.Warnings, "the group changes the node-engine's composition code and was composed by the running engines")
+	}
+	v.Took = time.Since(began).Milliseconds()
+	return v, nil
+}
+
+// JudgeEngines is the check's composition verdict from the engines' answers (ADR 0593 §7, §9): failed when any node's
+// answer is refused, naming each node and each module refused with its words (the first refusing node is the machine);
+// passed otherwise. Every node in nodes without an answer (silent, by node with why, for the journal only) is named
+// with delivery.ComposeNoAnswer as a warning. composer names what composed, for the line. Pure.
+func JudgeEngines(group, heads, composerName string, nodes []string, answers map[string]delivery.ComposeCandidateAnswer, silent map[string]string) delivery.CompositionVerdict {
+	v := delivery.CompositionVerdict{Group: group, Heads: heads, State: delivery.CompositionPass, SDK: composerName}
+	sorted := append([]string(nil), nodes...)
+	sort.Strings(sorted)
+	var fails []string
+	for _, node := range sorted {
+		a, answered := answers[node]
+		if !answered {
+			v.Warnings = append(v.Warnings, node+": "+delivery.ComposeNoAnswer)
+			continue
+		}
+		v.Machines = append(v.Machines, node)
+		if a.Verdict != delivery.ComposeCandidateRefused {
+			continue
+		}
+		if v.Machine == "" {
+			v.Machine = node
+		}
+		var words []string
+		if a.Refused != "" {
+			words = append(words, a.Refused)
+		}
+		for _, m := range append(append([]delivery.ModuleComposed(nil), a.Modules...), a.Own) {
+			if m.State == delivery.ModuleRefusedState {
+				words = append(words, m.Module+": "+m.Words)
+			}
+		}
+		if len(words) == 0 {
+			words = append(words, "refused, naming no module")
+		}
+		fails = append(fails, "not composed on "+node+": "+strings.Join(words, "; "))
+	}
+	if len(fails) > 0 {
+		v.State, v.Words = delivery.CompositionFail, strings.Join(fails, "; ")
+	}
+	if len(sorted) == 0 {
+		v.Warnings = append(v.Warnings, "no node is placed, so the change was composed on none")
+	}
+	return v
+}
+
+// inSandbox composes a node's answer again with the composer built from the node-engine member's head, over the input the
+// node's engine composed from: the node's answer becomes the sandbox's, refused with the composer's words where the
+// composer refuses the node.
+func (e EngineCompositions) inSandbox(ctx context.Context, c *Case, head, node string, a delivery.ComposeCandidateAnswer) (delivery.ComposeCandidateAnswer, error) {
+	if len(a.Input) == 0 {
+		return a, fmt.Errorf("the engine of %s answered no composition input, so the node-engine's head cannot compose it", node)
+	}
+	manifests := map[string]composer.Manifest{}
+	if e.Manifests != nil {
+		for name, digest := range e.Manifests.ManifestDigests() {
+			manifests[name] = composer.Manifest{Digest: digest}
+		}
+	}
+	for _, p := range c.Pulls {
+		for name, m := range p.Fps {
+			if m.Manifest != "" {
+				manifests[name] = composer.Manifest{Digest: m.Manifest}
+			}
+		}
+	}
+	verdicts := map[string]delivery.ManifestVerdict{}
+	if e.Verdicts != nil {
+		for name, v := range e.Verdicts() {
+			verdicts[name] = v
+		}
+	}
+	for _, p := range c.Pulls {
+		for name := range p.Fps {
+			delete(verdicts, name) // a manifest the change brings is the checker's own judge's (ADR 0578 §2)
+		}
+	}
+	req := composer.Request{V: composer.Version, Input: a.Input, Depth: composer.DepthCompose, Machines: []string{node},
+		Cases: []composer.Case{{Name: "change", Manifests: manifests, Verdicts: verdicts}}}
+	raw, err := json.Marshal(req)
+	if err != nil {
+		return a, err
+	}
+	job := delivery.ComposeJob{Fetch: map[string]any{"repository": nodeEngineRepo, "commit": head}, Dir: delivery.RootPath,
+		Package: composer.Package, Request: raw, Reader: "the node-engine head of " + c.Group}
+	verdict, err := e.Sandbox.Compose(ctx, job)
+	if err != nil {
+		return a, fmt.Errorf("the composer at the node-engine's head %s did not answer for %s: %w", head, node, err)
+	}
+	out := delivery.ComposeCandidateAnswer{V: a.V, Node: node, Candidate: a.Candidate, Verdict: delivery.ComposeCandidateComposed}
+	for _, cv := range verdict.Cases {
+		if m, ok := cv.Machines[node]; ok && !m.Composes {
+			out.Verdict = delivery.ComposeCandidateRefused
+			out.Refused = strings.Join(append(append([]string{m.Reason}, m.Problems...), m.Refusals...), "; ")
+		}
+		for name, read := range cv.Manifests {
+			if !read.Accepted {
+				out.Verdict = delivery.ComposeCandidateRefused
+				out.Modules = append(out.Modules, delivery.ModuleComposed{Module: name, State: delivery.ModuleRefusedState, Words: read.Refused})
+			}
+		}
+	}
+	sort.Slice(out.Modules, func(i, j int) bool { return out.Modules[i].Module < out.Modules[j].Module })
+	return out, nil
+}

modules/mesh-delivery-checker/internal/check/engines_test.go

@@ -0,0 +1,194 @@
+package check
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/composer"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// fakeEngines answers compose-candidate by node from memory; a node it holds no answer for never answers.
+type fakeEngines struct {
+	mu      sync.Mutex
+	answers map[string]delivery.ComposeCandidateAnswer
+	errs    map[string]error
+	asked   map[string]delivery.ComposeCandidateAsk
+}
+
+func (f *fakeEngines) ComposeCandidate(ctx context.Context, node string, ask delivery.ComposeCandidateAsk) (delivery.ComposeCandidateAnswer, error) {
+	f.mu.Lock()
+	if f.asked == nil {
+		f.asked = map[string]delivery.ComposeCandidateAsk{}
+	}
+	f.asked[node] = ask
+	a, ok := f.answers[node]
+	err := f.errs[node]
+	f.mu.Unlock()
+	if err != nil {
+		return delivery.ComposeCandidateAnswer{}, err
+	}
+	if !ok {
+		<-ctx.Done()
+		return delivery.ComposeCandidateAnswer{}, ctx.Err()
+	}
+	return a, nil
+}
+
+// fakeSandbox answers a compose job with a verdict, recording the job.
+type fakeSandbox struct {
+	mu   sync.Mutex
+	jobs []delivery.ComposeJob
+	v    func(node string) composer.Verdict
+	err  error
+}
+
+func (f *fakeSandbox) Compose(_ context.Context, job delivery.ComposeJob) (composer.Verdict, error) {
+	var req composer.Request
+	if err := json.Unmarshal(job.Request, &req); err != nil {
+		return composer.Verdict{}, err
+	}
+	f.mu.Lock()
+	f.jobs = append(f.jobs, job)
+	f.mu.Unlock()
+	if f.err != nil {
+		return composer.Verdict{}, f.err
+	}
+	return f.v(req.Machines[0]), nil
+}
+
+type digests map[string]string
+
+func (d digests) ManifestDigests() map[string]string { return d }
+
+// ADR 0593 §7, §9 (D12, G1, G2): the checker asks every placed node's engine in parallel and makes the composition from
+// their answers: a refusal fails it naming the node and each module; a node that does not answer within the bound,
+// answers unready or cannot be asked is named "not composed on that node: no answer" and the check passes with that
+// warning, decided by the verdict and never by its words; a group with a node-engine member is composed by the composer
+// built at that member's head, over the input each node's engine composed from.
+func TestTheCompositionIsMadeFromTheEnginesAnswers(t *testing.T) {
+	composed := func(node string) delivery.ComposeCandidateAnswer {
+		return delivery.ComposeCandidateAnswer{Node: node, Verdict: delivery.ComposeCandidateComposed,
+			Modules: []delivery.ModuleComposed{{Module: "web", State: delivery.ModuleComposedState, Digest: "sha256:" + strings.Repeat("a", 64)}},
+			Own:     delivery.ModuleComposed{Module: "node", State: delivery.ModuleComposedState, Digest: "sha256:" + strings.Repeat("b", 64)}}
+	}
+	cs := caseOf(t, pullOf(repoA, 7, head1))
+	key, _ := delivery.CompositionKey(cs.Group, cs.HeadsHash)
+	compose := func(e *fakeEngines, nodes ...string) delivery.CompositionVerdict {
+		t.Helper()
+		ec := EngineCompositions{Asker: e, Placed: func() ([]string, error) { return nodes, nil }, Bound: 50 * time.Millisecond,
+			Composer: func() string { return strings.Repeat("7", 40) }}
+		v, err := ec.Compose(context.Background(), cs)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return v
+	}
+
+	t.Run("one node refusing fails the composition, naming the node and the module", func(t *testing.T) {
+		refusing := composed("laptop")
+		refusing.Verdict = delivery.ComposeCandidateRefused
+		refusing.Modules = []delivery.ModuleComposed{{Module: "web", State: delivery.ModuleRefusedState, Words: "a required value is unset"},
+			{Module: "mail", State: delivery.ModuleHeldState, Words: "held as today"}}
+		e := &fakeEngines{answers: map[string]delivery.ComposeCandidateAnswer{"anchor": composed("anchor"), "laptop": refusing}}
+		v := compose(e, "anchor", "laptop")
+		if v.State != delivery.CompositionFail || v.Machine != "laptop" || !strings.Contains(v.Words, "not composed on laptop: web: a required value is unset") ||
+			strings.Contains(v.Words, "mail") || len(v.Machines) != 2 {
+			t.Errorf("verdict = %+v", v)
+		}
+		if e.asked["anchor"].Candidate != key || e.asked["laptop"].Input {
+			t.Errorf("asked %+v, want the check's candidate %s and no input", e.asked, key)
+		}
+		var ver delivery.Verdict
+		withComposition(&ver, v)
+		if ver.State != delivery.VerdictFail || ver.Failed.Machine != "laptop" {
+			t.Errorf("the check's verdict = %+v", ver)
+		}
+	})
+
+	t.Run("a silent, unready or unreachable node is no answer, and the check passes naming it", func(t *testing.T) {
+		unready := delivery.ComposeCandidateAnswer{Node: "g14", Verdict: delivery.ComposeCandidateUnready, Refused: "a module refused it"}
+		e := &fakeEngines{answers: map[string]delivery.ComposeCandidateAnswer{"anchor": composed("anchor"), "g14": unready},
+			errs: map[string]error{"ace": errors.New("no responders")}}
+		began := time.Now()
+		v := compose(e, "anchor", "laptop", "g14", "ace")
+		if took := time.Since(began); took > 2*time.Second {
+			t.Errorf("the nodes were not asked in parallel within the bound: %s", took)
+		}
+		if v.State != delivery.CompositionPass || v.SDK != strings.Repeat("7", 40) || len(v.Machines) != 1 {
+			t.Fatalf("verdict = %+v", v)
+		}
+		for _, node := range []string{"ace", "g14", "laptop"} {
+			if !strings.Contains(strings.Join(v.Warnings, "; "), node+": "+delivery.ComposeNoAnswer) {
+				t.Errorf("%s is not named: %v", node, v.Warnings)
+			}
+		}
+		var ver delivery.Verdict
+		ver.State = delivery.VerdictPass
+		withComposition(&ver, v)
+		if ver.State != delivery.VerdictPass || !strings.Contains(composition(ver.Composition, 0, false), "laptop: "+delivery.ComposeNoAnswer) {
+			t.Errorf("the line = %q", composition(ver.Composition, 0, false))
+		}
+	})
+
+	t.Run("a node-engine member is composed by the composer at its head over each node's input", func(t *testing.T) {
+		c, err := delivery.DecodeCandidate(candidateOf(t, "feat/x", pullOf(nodeEngineRepo, 3, head2), pullOf(repoA, 7, head1)))
+		if err != nil {
+			t.Fatal(err)
+		}
+		host := CaseOf(c, map[string]string{repoA: trunkA, nodeEngineRepo: trunkA})
+		withInput := composed("anchor")
+		withInput.Input = json.RawMessage(`{"nodes":[{"name":"anchor"}]}`)
+		e := &fakeEngines{answers: map[string]delivery.ComposeCandidateAnswer{"anchor": withInput}}
+		sb := &fakeSandbox{v: func(node string) composer.Verdict {
+			return composer.Verdict{V: composer.Version, Cases: []composer.CaseVerdict{{Name: "change",
+				Machines: map[string]composer.Machine{node: {Composes: false, Reason: "the new composer refuses it"}}}}}
+		}}
+		ec := EngineCompositions{Asker: e, Placed: func() ([]string, error) { return []string{"anchor"}, nil }, Bound: time.Second,
+			Sandbox: sb, Manifests: digests{"web": "sha256:" + strings.Repeat("c", 64)}}
+		v, err := ec.Compose(context.Background(), host)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !e.asked["anchor"].Input || len(sb.jobs) != 1 {
+			t.Fatalf("asked %+v, jobs %+v: want the input asked and one job", e.asked, sb.jobs)
+		}
+		job := sb.jobs[0]
+		var req composer.Request
+		_ = json.Unmarshal(job.Request, &req)
+		if job.Fetch["repository"] != nodeEngineRepo || job.Fetch["commit"] != head2 || job.Package != composer.Package ||
+			string(req.Input) != string(withInput.Input) || req.Cases[0].Manifests["web"].Digest == "" {
+			t.Errorf("job = %+v, request %+v", job, req)
+		}
+		if v.State != delivery.CompositionFail || v.SDK != head2 || !strings.Contains(v.Words, "the new composer refuses it") {
+			t.Errorf("verdict = %+v", v)
+		}
+		// Review finding 3 (ADR 0593 §9 lets only a node that does not answer pass): a composer at the head that cannot
+		// run fails the composition, naming the head, never passing as a silent node.
+		sb.err = errors.New("the build of mesh-compose failed")
+		v, err = ec.Compose(context.Background(), host)
+		if err != nil || v.State != delivery.CompositionFail || !strings.Contains(v.Words, head2) ||
+			!strings.Contains(v.Words, "the build of mesh-compose failed") || len(v.Warnings) != 0 {
+			t.Errorf("a composer that cannot run: %+v, %v", v, err)
+		}
+	})
+
+	// Review finding 4: a placement that cannot be read is no mesh with no node: the composition is not made, said.
+	t.Run("an unreadable placement makes no composition", func(t *testing.T) {
+		ec := EngineCompositions{Asker: &fakeEngines{}, Placed: func() ([]string, error) { return nil, errors.New("no such bucket") }}
+		if _, err := ec.Compose(context.Background(), cs); err == nil || !strings.Contains(err.Error(), "no such bucket") {
+			t.Errorf("an unreadable placement: %v", err)
+		}
+		b := newBench(t)
+		b.ex.Compositions = ec
+		v := b.judge(t, cs).Verdict
+		if v.Composition == nil || v.Composition.State != delivery.CompositionNotRun || !strings.Contains(v.Composition.Words, "no such bucket") {
+			t.Errorf("the verdict's composition = %+v", v.Composition)
+		}
+	})
+}

modules/mesh-delivery-checker/internal/check/examiner_test.go

@@ -18,10 +18,10 @@ import (
 	"time"
 	"unicode/utf8"
 
-	"git.novox.be/novox/mesh-sdk/go/buildstep"
+	gobuild "git.novox.be/novox/mesh-catalog/modules/mesh-build-go/buildstep"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/composer"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // captured reads a result the build module's own code marshalled (testdata/captured/README).
@@ -136,12 +136,12 @@ func refsOf(v any) []BesideRef {
 // toolPrefix is the start of each build module's tool names, as the fake build modules answer them.
 var toolPrefix = map[string]string{buildrun.GoBuildModule: "build_go_", buildrun.NodeBuildModule: "build_node_"}
 
-// answer runs a check ask as the build module that pulls it does (buildstep.RunAsk), with the fake tools on shanks and the
+// answer runs a check ask as the build module that pulls it does (gobuild.RunAsk), with the fake tools on shanks and the
 // bench's kept verdicts, and answers the step it writes.
 func (b *bench) answer(a delivery.StepAsk) delivery.Step {
 	module, _ := delivery.BuildModuleOf(a.Language)
 	const node = "shanks"
-	tool := func(name string) buildstep.StepFunc {
+	tool := func(name string) gobuild.StepFunc {
 		return func(ctx context.Context, args map[string]any) (any, error) {
 			raw, err := b.steps.Run(ctx, module, node, toolPrefix[module]+name, args)
 			if err != nil {
@@ -150,7 +150,7 @@ func (b *bench) answer(a delivery.StepAsk) delivery.Step {
 			return raw, nil
 		}
 	}
-	steps := buildstep.AskSteps{Fetch: tool("fetch"), Test: tool("test"),
+	steps := gobuild.AskSteps{Fetch: tool("fetch"), Test: tool("test"),
 		Kept: func(ctx context.Context, level, digest string) (int, bool, error) {
 			k, found, err := (Kept{Store: b.kept}).Lookup(ctx, level, digest)
 			return k.Tests, found, err
@@ -168,7 +168,7 @@ func (b *bench) answer(a delivery.StepAsk) delivery.Step {
 		}
 		steps.Has = func(string) bool { return true }
 	}
-	out, err := buildstep.RunAsk(context.Background(), steps, a)
+	out, err := gobuild.RunAsk(context.Background(), steps, a)
 	step := delivery.Step{ID: a.ID, Tool: a.Kind + " ask", Node: node, State: delivery.StepPassed, Started: began, Ended: began.Add(2 * time.Second)}
 	if err != nil {
 		step.State, step.Reason = delivery.StepFailed, err.Error()

modules/mesh-delivery-checker/internal/check/judge.go

@@ -3,7 +3,6 @@ package check
 import (
 	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"path"
 	"slices"
@@ -11,9 +10,9 @@ import (
 	"strings"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // goModule is the build module the Go repositories are judged by.
@@ -117,9 +116,8 @@ type Examiner struct {
 	Manifests TrunkManifests
 	// Predefined reads the catalogue's predefined keys the indexer keeps (manifests_judge.go); nil reads none.
 	Predefined PredefinedList
-	// Compositions answers the assigner's composition check of a check by the check's key (delivery.CompositionKey),
-	// waiting until the assigner wrote a verdict that does not wait, or ctx ends (ADR 0528 clause 5, issue 1297); nil
-	// leaves the composition not run.
+	// Compositions makes a check's composition (ADR 0593 §7): the engines' answers (EngineCompositions); nil leaves the
+	// composition not run.
 	Compositions CompositionReader
 	// Nodes names every node with a record, read from each `<node>.node` of the node-engine's have (novox/hq ADR 0567
 	// §12): every check ask carries them (CheckJob.NodeNames) for the names check, so no repository lists them. A check
@@ -131,10 +129,9 @@ type Examiner struct {
 	Logf func(format string, args ...any)
 }
 
-// CompositionReader answers the assigner's composition of a check by the check's key, waiting until the assigner wrote
-// a verdict that does not wait, or ctx ends.
+// CompositionReader makes a check's composition verdict; an error is only a case that cannot be composed at all.
 type CompositionReader interface {
-	Await(ctx context.Context, key string) (delivery.CompositionVerdict, error)
+	Compose(ctx context.Context, c *Case) (delivery.CompositionVerdict, error)
 }
 
 func (j *Examiner) now() time.Time {
@@ -260,9 +257,9 @@ func (st *state) finish(ctx context.Context, v delivery.Verdict) Outcome {
 	return out
 }
 
-// composed reads the assigner's composition of the check into its verdict (ADR 0528 clause 5): a failed composition
-// fails the check, naming the machine it failed at. A try is not composed (it has no candidate); a composition that
-// cannot be had leaves it not run, said; with no assigner running it is not judged, said at once.
+// composed makes the check's composition from the engines' answers into its verdict (ADR 0593 §7, §9): a failed
+// composition fails the check, naming the machine it failed at; a node that did not answer is a warning. A try is not
+// composed (it has no candidate); a composition that cannot be made leaves it not run, said.
 func (st *state) composed(ctx context.Context, v *delivery.Verdict) {
 	if st.c.Composition != nil && st.c.Try == nil {
 		// A carry whose candidate's fingerprints did not change keeps the composition it passed (ADR 0548 §5).
@@ -275,18 +272,16 @@ func (st *state) composed(ctx context.Context, v *delivery.Verdict) {
 		return
 	}
 	if len(st.unpreviewed) > 0 {
-		// The assigner would only say it waits for a manifest the indexer will not have: the check does not wait for it.
+		// An engine would only say it cannot read a manifest the indexer will not have: the check does not ask it.
 		v.Composition = &delivery.Composition{State: delivery.CompositionNotRun, Words: "no preview of a merge of " +
 			strings.Join(st.unpreviewed, ", ") + " (its head does not merge or its fetch did not answer), so the change cannot be composed"}
 		return
 	}
-	comp, err := st.j.Compositions.Await(ctx, st.c.Key)
-	switch {
-	case errors.Is(err, ErrAssignerNotRunning):
-		v.Composition = &delivery.Composition{State: delivery.CompositionNotRun, Words: delivery.AssignerNotRunning}
-		return
-	case err != nil:
-		st.j.logf("%s: the composition could not be read, so it is said as not run: %v", st.c.Key, err)
+	comp, err := st.j.Compositions.Compose(ctx, st.c)
+	if err != nil {
+		// Said in the verdict, never left as a composition not yet run (review finding 4).
+		st.j.logf("%s: the composition could not be made, so it is said as not run: %v", st.c.Key, err)
+		v.Composition = &delivery.Composition{State: delivery.CompositionNotRun, Words: "not made: " + err.Error()}
 		return
 	}
 	withComposition(v, comp)
@@ -315,7 +310,7 @@ func (st *state) outcome(v delivery.Verdict) Outcome {
 			v.OverBound = append(v.OverBound, level)
 		}
 	}
-	// The composition is the assigner's check (issue 1297): until it delivers a verdict says it was not run (ADR 0484 clause 6).
+	// The composition is made from the engines' answers (ADR 0593 §7): until it is, a verdict says it was not run (ADR 0484 clause 6).
 	v.Composition = &delivery.Composition{State: delivery.CompositionNotRun}
 	var slow []string
 	for _, level := range []string{delivery.LevelUnit, delivery.LevelIntegration} {

modules/mesh-delivery-checker/internal/check/line.go

@@ -156,8 +156,8 @@ func levelWords(name string, r delivery.LevelResult) string {
 	return s
 }
 
-// compositionWords says the composition: not yet run, or once the assigner's check reports it (issue 1297) passed or
-// failed, with the time it took and the machines it composed (issue 1300).
+// compositionWords says the composition: not yet run, or once the engines answered (ADR 0593 §7) passed, with the nodes
+// that gave no answer, or failed, with the time it took and the machines it composed (issue 1300).
 func compositionWords(c *delivery.Composition, took int64) string { return composition(c, took, false) }
 
 // composition is compositionWords; short counts the machines and leaves the SDK commit to the report.
@@ -183,11 +183,15 @@ func composition(c *delivery.Composition, took int64, short bool) string {
 			on = fmt.Sprintf(" on %d machines: %s", len(machines), strings.Join(machines, ", "))
 		}
 	}
+	warned := ""
+	if c.State == delivery.CompositionPass && c.Words != "" {
+		warned = " (" + c.Words + ")" // a node that did not answer (ADR 0593 §9)
+	}
 	switch {
 	case c.State == delivery.CompositionPass && short:
-		return "composition passed" + in + on // the SDK it composed with is in the report
+		return "composition passed" + in + on + warned // what it composed with is in the report
 	case c.State == delivery.CompositionPass:
-		return "composition passed" + in + " with " + short12(c.SDK) + on
+		return "composition passed" + in + " with " + short12(c.SDK) + on + warned
 	}
 	return "composition failed" + in + on + ": " + c.Words
 }

modules/mesh-delivery-checker/internal/check/lostask.go

@@ -3,9 +3,9 @@ package check
 import (
 	"strings"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // **An ask the build seat gave up on ends its step** (novox/hq issue 734): mesh-sdk buildrun.LostAskWaiter hands the

modules/mesh-delivery-checker/internal/check/lostask_test.go

@@ -8,9 +8,9 @@ import (
 	"testing"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // losingAsks is the build seat over a bus that gives up the first `lose` asks put (DEAD_LETTERS keeps them, as on

modules/mesh-delivery-checker/internal/check/pins_test.go

@@ -81,66 +81,46 @@ func besideOf(t *testing.T, b *bench, repository string) map[string]BesideRef {
 }
 
 func TestTheSiblingsAreWhereTheTestsStateThem(t *testing.T) { // review D2, ADR 0484 clause 4
-	const controller, catalogue, host = "novox/mesh-controller", "novox/mesh-catalog", "novox/mesh-host"
+	const catalogue, host, controller = "novox/mesh-catalog", "novox/mesh-host", "novox/mesh-controller"
 	hostRuns := strings.Repeat("7", 40)
 	b := newBench(t)
-	b.ex.Trunks = trunksOf(t, map[string]string{controller: trunkA, catalogue: trunkS, host: trunkA2, SDKRepository: "9999999999999999999999999999999999999999"})
+	b.ex.Trunks = trunksOf(t, map[string]string{SDKRepository: trunkS, catalogue: trunkA, host: trunkA2})
 	b.ex.Runs = runsAt{"mesh-host": hostRuns}
-	// A group of the controller and the catalogue: the controller's tests read the group's catalogue head, the heads the group
-	// merges (ADR 0482 §2, ADR 0573 §4; issue 1126: a judge in the group was judged against the catalogue's trunk).
-	out := b.judge(t, caseOf(t, pullOf(controller, 7, head1), pullOf(catalogue, 12, head2)))
-	// ADR 0548 §6, issue 568's own example: the verdict names the node-engine at the commit the mesh runs, and mesh-sdk at the
-	// trunk the catalogue's tests read it at; the catalogue, a member here, is not named.
-	if out.Beside[host] != hostRuns || out.Beside[catalogue] != "" || out.Beside[SDKRepository] != "9999999999999999999999999999999999999999" {
-		t.Errorf("the siblings named for the verdict = %v, want the node-engine at %s and mesh-sdk at its trunk", out.Beside, hostRuns[:12])
+	// A group of mesh-sdk and the catalogue: mesh-sdk's tests read the group's catalogue head, the heads the group merges
+	// (ADR 0482 §2, ADR 0573 §4; issue 1126: a judge in the group was judged against the catalogue's trunk).
+	out := b.judge(t, caseOf(t, pullOf(SDKRepository, 7, head1), pullOf(catalogue, 12, head2)))
+	// ADR 0548 §6, issue 568's own example: the verdict names the node-engine at the commit the mesh runs; the catalogue,
+	// a member here, is not named.
+	if out.Beside[host] != hostRuns || out.Beside[catalogue] != "" {
+		t.Errorf("the siblings named for the verdict = %v, want the node-engine at %s", out.Beside, hostRuns[:12])
 	}
-	got := besideOf(t, b, controller)
+	got := besideOf(t, b, SDKRepository)
 	if c := got[catalogue]; c.Commit != head2 || c.Ref != "refs/pull/12/head" {
-		t.Errorf("the catalogue beside the controller in a group = %+v, want the member's head %s", c, head2)
+		t.Errorf("the catalogue beside mesh-sdk in a group = %+v, want the member's head %s", c, head2)
 	}
 	if h := got[host]; h.Commit != hostRuns {
-		t.Errorf("the node-engine beside the controller = %+v, want the commit the mesh runs %s", h, hostRuns)
+		t.Errorf("the node-engine beside mesh-sdk = %+v, want the commit the mesh runs %s", h, hostRuns)
 	}
-	// ADR 0573 §2: the controller is built against mesh-sdk's latest published version, so its tests read that one too,
-	// not the commit its go.mod names.
-	if s := got[SDKRepository]; s.Commit != "9999999999999999999999999999999999999999" {
-		t.Errorf("mesh-sdk beside the controller = %+v, want its trunk", s)
+	// Alone, mesh-sdk's tests read the catalogue's trunk, and the verdict names it.
+	b = newBench(t)
+	b.ex.Trunks = trunksOf(t, map[string]string{SDKRepository: trunkS, catalogue: trunkA, host: trunkA2})
+	if out := b.judge(t, caseOf(t, pullOf(SDKRepository, 7, head1))); out.Beside[catalogue] != trunkA {
+		t.Errorf("the siblings named for the verdict alone = %v, want the catalogue at its trunk %s", out.Beside, trunkA)
 	}
-	// Alone, the controller's tests read the catalogue's trunk, and the verdict names it.
+	if c := besideOf(t, b, SDKRepository)[catalogue]; c.Commit != trunkA || c.Ref != "" {
+		t.Errorf("the catalogue beside mesh-sdk alone = %+v, want its trunk %s", c, trunkA)
+	}
+	// 1126/B8 (novox/hq ADR 0590, ADR 0593 §11): the controller's repository is emptied and archived, so no repository's
+	// tests read it and it has no siblings of its own: a pull request of it has only its own trunk beside it.
 	b = newBench(t)
 	b.ex.Trunks = trunksOf(t, map[string]string{controller: trunkA, catalogue: trunkS, host: trunkA2, SDKRepository: trunkS})
-	if out := b.judge(t, caseOf(t, pullOf(controller, 7, head1))); out.Beside[catalogue] != trunkS {
-		t.Errorf("the siblings named for the verdict alone = %v, want the catalogue at its trunk %s", out.Beside, trunkS)
-	}
-	if c := besideOf(t, b, controller)[catalogue]; c.Commit != trunkS || c.Ref != "" {
-		t.Errorf("the catalogue beside the controller alone = %+v, want its trunk %s", c, trunkS)
-	}
-}
-
-// 1126/B8 (novox/hq ADR 0590): the controller is gone, so no repository's tests read it: a mesh-host pull request has
-// the catalogue and mesh-sdk beside it and no mesh-controller, even where its trunk is known and the group holds one.
-func TestNoRepositorysTestsHaveTheControllerBesideThem(t *testing.T) {
-	const host = "novox/mesh-host"
-	b := newBench(t)
-	b.ex.Trunks = trunksOf(t, map[string]string{host: trunkA, controllerRepo: trunkA2, catalogueRepository: trunkS, SDKRepository: trunkS})
-	c, err := delivery.DecodeCandidate(candidateOf(t, "feat/x", pullOf(host, 5, head1), pullOf(controllerRepo, 9, head2)))
-	if err != nil {
-		t.Fatal(err)
-	}
-	if v := b.judge(t, CaseOf(c, map[string]string{host: trunkA, controllerRepo: trunkA2})).Verdict; v.State == delivery.VerdictFail &&
-		strings.Contains(v.Failed.Words, "mesh-controller") {
-		t.Fatalf("verdict = %+v", v)
-	}
-	got := besideOf(t, b, host)
-	if _, ok := got[controllerRepo]; ok {
-		t.Errorf("the controller is beside the node-engine: %+v", got)
-	}
-	if _, ok := got[catalogueRepository]; !ok {
-		t.Errorf("the catalogue is not beside the node-engine: %+v", got)
+	b.judge(t, caseOf(t, pullOf(controller, 9, head2)))
+	if got := besideOf(t, b, controller); len(got) != 1 || got[controller].Commit != trunkA {
+		t.Errorf("beside the controller's own change = %+v, want its own trunk alone", got)
 	}
 	for repo, siblings := range besideRules {
-		if repo != controllerRepo && slices.Contains(siblings, controllerRepo) {
-			t.Errorf("the tests of %s read the controller", repo)
+		if repo == controller || slices.Contains(siblings, controller) {
+			t.Errorf("the tests of %s read the controller, or it has siblings", repo)
 		}
 	}
 }
@@ -160,10 +140,10 @@ func TestTheChangesOwnRepositoryIsBesideItAtItsTrunk(t *testing.T) {
 // the catalogue's shrink-only list tests read $MESH_CHECK_BESIDE/mesh-catalog.
 func TestACatalogueChangeHasTheCatalogueBesideItAtItsTrunk(t *testing.T) {
 	b := newBench(t)
-	b.ex.Trunks = trunksOf(t, map[string]string{catalogueRepository: trunkA, SDKRepository: trunkS, controllerRepo: trunkA2})
+	b.ex.Trunks = trunksOf(t, map[string]string{catalogueRepository: trunkA, SDKRepository: trunkS, "novox/mesh-controller": trunkA2})
 	out := b.judge(t, caseOf(t, pullOf(catalogueRepository, 12, head1)))
 	// ADR 0548 §6: the outcome names the siblings read at their trunk's head, never the repository it merges.
-	if out.Beside[SDKRepository] != trunkS || out.Beside[controllerRepo] != "" || out.Beside[catalogueRepository] != "" {
+	if out.Beside[SDKRepository] != trunkS || out.Beside["novox/mesh-controller"] != "" || out.Beside[catalogueRepository] != "" {
 		t.Errorf("the siblings named for the verdict = %v, want mesh-sdk at its trunk and neither the controller nor the catalogue", out.Beside)
 	}
 	got := besideOf(t, b, catalogueRepository)

modules/mesh-delivery-checker/internal/check/read.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // The read tools (novox/hq ADR 0484 clauses 8 and 13, issue 1686): what the checker stored, as stored, with the line of the

modules/mesh-delivery-checker/internal/check/try.go

@@ -13,8 +13,8 @@ import (
 	"sync"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/buildrun"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
-	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
 
 // A try is a pushed head judged by the checker as a pull request's head is, before its pull request is opened (ADR 0501

modules/mesh-delivery-checker/manifest_test.go

@@ -54,10 +54,13 @@ type manifest struct {
 	Uses     []string `json:"uses"`
 	Invokes  []string `json:"invokes"`
 	Config   map[string]struct {
-		Type        string `json:"type"`
-		Description string `json:"description"`
-		Pattern     string `json:"pattern"`
-		Default     string `json:"default"`
+		Type        string   `json:"type"`
+		Description string   `json:"description"`
+		Pattern     string   `json:"pattern"`
+		Default     any      `json:"default"`
+		Minimum     *float64 `json:"minimum"`
+		Maximum     *float64 `json:"maximum"`
+		Trusted     bool     `json:"trusted"`
 	} `json:"config"`
 	OwnSecrets   map[string]string `json:"own-secrets"`
 	SecretsOwner string            `json:"secrets-owner"`
@@ -102,14 +105,17 @@ func TestManifestDeclarations(t *testing.T) { // 1678/AC1
 		t.Errorf("state = %+v, want %+v", m.State, want)
 	}
 	if want := []string{"mesh-build-go.steps", "mesh-build-go.toolchains", "mesh-build-node.steps", "mesh-build-node.toolchains",
-		"mesh-delivery-assigner.compositions", "mesh-delivery-assigner.placement", "mesh-delivery-builder.builds", "mesh-delivery-gate.source", "mesh-delivery-gate.turns", "mesh-delivery-indexer.candidates",
-		"mesh-delivery-indexer.manifests", "mesh-delivery-indexer.modules", "mesh-delivery-indexer.predefined", "mesh-delivery-watchman.presence", "node-engine.have"}; !reflect.DeepEqual(sorted(m.Reads), want) {
+		"mesh-delivery-assigner.placement", "mesh-delivery-builder.builds", "mesh-delivery-gate.source", "mesh-delivery-gate.turns", "mesh-delivery-indexer.candidates",
+		"mesh-delivery-indexer.manifests", "mesh-delivery-indexer.modules", "mesh-delivery-indexer.packages", "mesh-delivery-indexer.predefined", "mesh-delivery-watchman.presence", "node-engine.have"}; !reflect.DeepEqual(sorted(m.Reads), want) {
 		t.Errorf("reads = %v, want %v", m.Reads, want)
 	}
 	// 1887/A5b: the checker reads nothing of the controller's plans-building (ADR 0483 superseded by ADR 0525 §7), calls no
 	// build module's tool and holds no capacity: it puts check asks on the Go and Node build seats (ADR 0525 §1, §4).
-	if want := []string{"gitea.gitea_commits", "gitea.gitea_compare", "gitea.gitea_get_file", "gitea.gitea_list_branches"}; !reflect.DeepEqual(sorted(m.Invokes), want) {
-		t.Errorf("invokes = %v, want only the forge's reads for a mesh-sdk pin (ADR 0484 clause 9)", m.Invokes)
+	// The forge's reads for a mesh-sdk pin (ADR 0484 clause 9), and of the node seat node-engine its one verb
+	// compose-candidate, asked of every placed node (ADR 0593 §7), never the seat's other verbs.
+	if want := []string{"gitea.gitea_commits", "gitea.gitea_compare", "gitea.gitea_get_file", "gitea.gitea_list_branches",
+		"seat:node-engine.compose-candidate"}; !reflect.DeepEqual(sorted(m.Invokes), want) {
+		t.Errorf("invokes = %v, want the forge's reads and compose-candidate", m.Invokes)
 	}
 	if want := []string{"node-build-go", "node-build-node"}; !reflect.DeepEqual(sorted(m.Uses), want) {
 		t.Errorf("uses = %v, want the Go and Node build seats", m.Uses)
@@ -139,7 +145,7 @@ func TestManifestDeclarations(t *testing.T) { // 1678/AC1
 		!reflect.DeepEqual(m.Claims[0].Serves, []string{"try", "try-read", "try-end"}) {
 		t.Errorf("claims = %+v, want the mesh seat mesh-delivery-checker serving try, try-read and try-end", m.Claims)
 	}
-	for _, k := range []string{"logs", "emits", "provides", "requires", "defines-seats", "seat", "seats", "bus", "config"} {
+	for _, k := range []string{"logs", "emits", "provides", "requires", "defines-seats", "seat", "seats", "bus"} { // config: compose-answer-bound (ADR 0593 §7)
 		if _, ok := top[k]; ok {
 			t.Errorf("the manifest declares %q: the checker has none", k)
 		}
@@ -165,14 +171,19 @@ func TestManifestProcess(t *testing.T) { // 1678/AC1
 		t.Errorf("process = %v", p)
 	}
 	env, _ := p["env"].(map[string]any)
-	if len(env) != 1 || env["MESH_BROKER_FILE"] != "${dir:state}/broker" {
-		t.Errorf("env = %v, want the broker file alone", p["env"])
+	if len(env) != 2 || env["MESH_BROKER_FILE"] != "${dir:state}/broker" || env["MESH_CHECKER_SETTINGS"] != "${dir:state}/settings.json" {
+		t.Errorf("env = %v, want the broker file and the settings file", p["env"])
 	}
+	// Its settings hold its answer bound alone (ADR 0593 §7: compose-answer-bound, 60 s, the checker's), never a capacity
+	// of its own (ADR 0525 §4).
 	for _, r := range m.Resources {
-		if r["id"] == "settings" {
-			t.Errorf("a settings resource %v: the checker has no capacity of its own (ADR 0525 §4)", r)
+		if r["id"] == "settings" && !reflect.DeepEqual(r["takes-config"], []any{"compose-answer-bound"}) {
+			t.Errorf("the settings resource %v takes more than compose-answer-bound", r)
 		}
 	}
+	if c, ok := m.Config["compose-answer-bound"]; !ok || c.Default != float64(60) || c.Trusted {
+		t.Errorf("compose-answer-bound = %+v, want 60 by default, not trusted", c)
+	}
 	if _, bus := p["bus"]; bus {
 		t.Errorf("the process declares a bus: it runs on its own broker credential")
 	}