Merge pull request 'A change that adds a compiled binary is refused, in any repository (issue 1577)' (#99) from fix/1577-checker-refuses-binaries into main

The mirror of jschoubben/car-hunter on ace said only "git -C: error:": git writes a bare
"error:" before the forge's message, and the reason kept the first non-empty line. forgekey.Said
keeps every line that says something, leaves bare prefixes out, joins them and bounds them at
600 bytes; every git and ssh-keygen reason of buildstep and forgekey goes through it, and the
mirror's commands are named by their verb, not by -C.

go/announce/announce.go

@@ -46,6 +46,10 @@ func Key(module string) (string, error) {
 type State struct {
 	Name     string `json:"name"`
 	Readable bool   `json:"readable,omitempty"`
+	// Readers, when named, are the only modules that may read the state (novox/hq ADR 0547 clause 9, issue 1945): a
+	// state readable by some and not all, such as the vault's bus account hashes. Only ReadableBy grants them; Readable,
+	// which a composer that knows no readers asks, stays false for it, so such a composer grants nobody.
+	Readers []string `json:"readers,omitempty"`
 }
 
 // States is an announcement: the module, the machine whose instance said it, and every state the module keeps, sorted
@@ -67,6 +71,26 @@ func (s States) Keeps(state string) bool {
 	return false
 }
 
+// ReadableBy says whether the module announced the state readable by reader: readable, and reader among the readers
+// when it names any.
+func (s States) ReadableBy(state, reader string) bool {
+	for _, k := range s.States {
+		if k.Name != state {
+			continue
+		}
+		if len(k.Readers) > 0 {
+			for _, r := range k.Readers {
+				if r == reader {
+					return true
+				}
+			}
+			return false
+		}
+		return k.Readable
+	}
+	return false
+}
+
 // Readable says whether the module announced the state readable by others.
 func (s States) Readable(state string) bool {
 	for _, k := range s.States {
@@ -93,6 +117,11 @@ func (s *States) check() error {
 			return fmt.Errorf("announce: %s announces the state %q twice", s.Module, k.Name)
 		}
 		seen[k.Name] = true
+		for _, r := range k.Readers {
+			if !name.MatchString(r) {
+				return fmt.Errorf("announce: %s names %q as a reader of %s, and a reader is a module: lower-case letters, digits and hyphens", s.Module, r, k.Name)
+			}
+		}
 	}
 	return nil
 }

go/announce/announce_test.go

@@ -9,7 +9,8 @@ import (
 // own event subject, in a versioned value the controller keeps by module.
 func TestAnAnnouncementRoundTripsSortedAndSaysWhatIsReadable(t *testing.T) {
 	data, err := Encode(States{Module: "mesh-controller", Node: "novox", States: []State{
-		{Name: "plans-building", Readable: true}, {Name: "assignments", Readable: true}, {Name: "own"}}})
+		{Name: "plans-building", Readable: true}, {Name: "assignments", Readable: true}, {Name: "own"},
+		{Name: "hashes", Readers: []string{"mesh-grants"}}}})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -24,12 +25,17 @@ func TestAnAnnouncementRoundTripsSortedAndSaysWhatIsReadable(t *testing.T) {
 	for _, s := range back.States {
 		names = append(names, s.Name)
 	}
-	if strings.Join(names, ",") != "assignments,own,plans-building" {
+	if strings.Join(names, ",") != "assignments,hashes,own,plans-building" {
 		t.Fatalf("the states are not sorted: %v", names)
 	}
 	if !back.Readable("plans-building") || back.Readable("own") || back.Readable("absent") {
 		t.Fatal("Readable does not say what was announced readable")
 	}
+	// Named readers (ADR 0547 clause 9): readable by them alone, and not readable to a composer that knows no readers.
+	if back.Readable("hashes") || !back.ReadableBy("hashes", "mesh-grants") || back.ReadableBy("hashes", "spy") ||
+		!back.ReadableBy("plans-building", "spy") || back.ReadableBy("own", "spy") {
+		t.Fatal("ReadableBy does not say who was named")
+	}
 	if !back.Keeps("own") || back.Keeps("absent") {
 		t.Fatal("Keeps does not say what was announced")
 	}
@@ -57,6 +63,7 @@ func TestAnAnnouncementRefusesWhatNoBucketCouldBe(t *testing.T) {
 		{States{Module: "a", States: []State{{Name: "x_y"}}}, `"x_y"`},
 		{States{Module: "a", States: []State{{Name: ""}}}, `""`},
 		{States{Module: "a", States: []State{{Name: "x"}, {Name: "x", Readable: true}}}, "twice"},
+		{States{Module: "a", States: []State{{Name: "x", Readers: []string{"b.c"}}}}, `"b.c"`},
 	} {
 		if _, err := Encode(c.s); err == nil || !strings.Contains(err.Error(), c.says) {
 			t.Errorf("%+v: %v, wanted a refusal saying %s", c.s, err, c.says)

go/buildcpu/buildcpu.go

@@ -0,0 +1,215 @@
+// Package buildcpu is how much of a build node's processors its builds may take, and how they yield to everything else
+// there (novox/hq ADR 0553, issue 1806; the operator, 2026-10-26: "limit CPU usage on our build nodes so the total cpu
+// usage never impacts the normal workings of our nodes ... We have 3 build agents so they should share the cpu power").
+//
+// Three parts, each with one owner:
+//
+//   - **Priority.** A build seat's holder (catalogue.Seat.Yields) runs at the lowest priority there is: the composer
+//     gives its runtime process declaration.Yields, and the node-engine places every yielding process of the node in
+//     one slice (declaration.YieldSlice) whose CPU weight is idle, with Nice=19 for every process it starts.
+//     Interactive and service work always comes first; builds take the cycles nothing else wants.
+//   - **One cap per node, shared.** The node's share of its processors is one value, the node-engine's own config
+//     `build-cpu-share` (ShareSetting), set per node through the node's settings layer. The node-engine writes it as the
+//     slice's CPUQuota: one bound the kernel holds for all the node's build modules together, never one per module.
+//   - **Threads.** The quota bounds the total; threads only size each step. A step gets the share divided by its own
+//     module's capacity (Threads), from the share the composer hands as a word (ShareWord): GOMAXPROCS sets every go
+//     command's -p, the compiler's concurrency, a test binary's processors and -parallel. A module given no word sets
+//     no thread limit at all: without the slice there is nothing to size a step to, and a limit then would only slow
+//     builds.
+package buildcpu
+
+import (
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+)
+
+// ShareSetting is the node-engine's config value of the node's processor share for its builds, in percent of the
+// machine's processors, 1 to 100: one value per node, set through the node's settings layer (novox/hq ADR 0553 §3).
+const ShareSetting = "build-cpu-share"
+
+// DefaultPercent is the share where nothing sets one: half the machine, so a desktop keeps half its processors for
+// itself whatever builds.
+const DefaultPercent = 50
+
+// ShareWord is the word the composer gives every yielding module (novox/hq ADR 0553 §4): the node's share, in percent.
+const ShareWord = "MESH_BUILD_CPU_SHARE"
+
+// Quota is a CPUQuota for a share of a machine with cores processors: systemd counts a quota in percent of one
+// processor, so half of 24 is 1200%. At least 100%, one processor, so a share on a small machine never stops a step.
+func Quota(percent, cores int) int {
+	q := percent * cores
+	if q < 100 {
+		q = 100
+	}
+	return q
+}
+
+// Threads is how many threads one step may run at once: its part of the share when its own module runs slots steps at
+// once, at least one. The slice's quota bounds the steps of all the node's build modules together; this only sizes one.
+func Threads(percent, cores, slots int) int {
+	if slots < 1 {
+		slots = 1
+	}
+	if percent < 1 || percent > 100 {
+		percent = DefaultPercent
+	}
+	t := cores * percent / 100 / slots
+	if t < 1 {
+		t = 1
+	}
+	return t
+}
+
+// Limits is what one step is held to on this node, as a status tool says it.
+type Limits struct {
+	// Percent is the node's share in percent of its processors, and From where it was read: ShareWord, or "none" when
+	// the composer gave no share and a step runs without a thread limit.
+	Percent int    `json:"share-percent,omitempty"`
+	From    string `json:"share-from"`
+	// Cores is the machine's processor count.
+	Cores int `json:"cores"`
+	// Slots is this module's own capacity on the node: steps at once.
+	Slots int `json:"slots"`
+	// Threads is what each step is given (Threads); 0 is no limit.
+	Threads int `json:"threads-per-step"`
+}
+
+// FromWords is the limits of a step from the share the composer gave this process (ShareWord) and the module's own
+// capacity. Without a usable share there is no limit: Threads is 0.
+func FromWords(getenv func(string) string, own int) Limits {
+	if own < 1 {
+		own = 1
+	}
+	l := Limits{From: "none", Cores: runtime.NumCPU(), Slots: own}
+	if n, err := strconv.Atoi(strings.TrimSpace(getenv(ShareWord))); err == nil && n >= 1 && n <= 100 {
+		l.Percent, l.From = n, ShareWord
+		l.Threads = Threads(n, l.Cores, own)
+	}
+	return l
+}
+
+// Env is the environment a step's commands are given so they start no more threads than they may: GOMAXPROCS for every
+// Go program (the compiler, a test binary, esbuild, buildah), UV_THREADPOOL_SIZE for Node's worker pool. Returned as
+// KEY=value words to append to a command's environment; nothing for 0 threads, no limit.
+func Env(threads int) []string {
+	if threads < 1 {
+		return nil
+	}
+	t := strconv.Itoa(threads)
+	return []string{"GOMAXPROCS=" + t, "UV_THREADPOOL_SIZE=" + t}
+}
+
+// InForce is what the kernel holds this process to, read rather than assumed (evidence over assertion): its nice
+// level, its cgroup (the unit) and the cgroup's parent (the slice the node-engine placed it in), each one's CPU weight,
+// idle mark and quota. A field the machine does not answer is left empty and Unread says which.
+//
+// The IO weight is read but binds only where the disk's scheduler honours it (bfq, or the io.cost controller); under
+// the scheduler `none`, the usual one for NVMe, it does nothing, and the CPU bound is what holds.
+type InForce struct {
+	Nice   int    `json:"nice"`
+	Cgroup string `json:"cgroup,omitempty"`
+	Unit   Group  `json:"unit"`
+	Slice  Group  `json:"slice"`
+	// Quota is the tighter of the two groups' cpu.max as a percent of one processor, 0 with none.
+	Quota  int      `json:"quota-percent,omitempty"`
+	Unread []string `json:"unread,omitempty"`
+}
+
+// Group is one cgroup's controls.
+type Group struct {
+	Path      string `json:"path,omitempty"`
+	CPUIdle   string `json:"cpu-idle,omitempty"`
+	CPUWeight string `json:"cpu-weight,omitempty"`
+	// CPUMax is the cgroup's cpu.max: "<quota µs> <period µs>", or "max" with no quota.
+	CPUMax   string `json:"cpu-max,omitempty"`
+	IOWeight string `json:"io-weight,omitempty"`
+}
+
+// cgroupRoot is where the unified hierarchy is mounted. A variable so a test can point it elsewhere.
+var cgroupRoot = "/sys/fs/cgroup"
+
+// procSelfCgroup is this process's cgroup file. A variable so a test can point it elsewhere.
+var procSelfCgroup = "/proc/self/cgroup"
+
+// procSelfStat is this process's stat file. A variable so a test can point it elsewhere.
+var procSelfStat = "/proc/self/stat"
+
+// ReadInForce reads what the kernel holds this process to.
+func ReadInForce() InForce {
+	var f InForce
+	f.Nice = nice()
+	raw, err := os.ReadFile(procSelfCgroup)
+	if err != nil {
+		f.Unread = append(f.Unread, "cgroup: "+err.Error())
+		return f
+	}
+	for _, line := range strings.Split(strings.TrimSpace(string(raw)), "\n") {
+		if strings.HasPrefix(line, "0::") {
+			f.Cgroup = strings.TrimPrefix(line, "0::")
+		}
+	}
+	if f.Cgroup == "" {
+		f.Unread = append(f.Unread, "cgroup: not on the unified hierarchy")
+		return f
+	}
+	read := func(path string) Group {
+		g := Group{Path: path}
+		value := func(name string) string {
+			b, err := os.ReadFile(cgroupRoot + path + "/" + name)
+			if err != nil {
+				f.Unread = append(f.Unread, path+"/"+name+": "+err.Error())
+				return ""
+			}
+			return strings.TrimSpace(string(b))
+		}
+		g.CPUIdle, g.CPUWeight, g.CPUMax, g.IOWeight = value("cpu.idle"), value("cpu.weight"), value("cpu.max"), value("io.weight")
+		return g
+	}
+	f.Unit = read(f.Cgroup)
+	if i := strings.LastIndex(f.Cgroup, "/"); i > 0 {
+		f.Slice = read(f.Cgroup[:i])
+	}
+	for _, q := range []int{quotaOf(f.Unit.CPUMax), quotaOf(f.Slice.CPUMax)} {
+		if q > 0 && (f.Quota == 0 || q < f.Quota) {
+			f.Quota = q
+		}
+	}
+	return f
+}
+
+// quotaOf is a cpu.max value as a percent of one processor: "1200000 100000" is 1200; "max ..." or nothing is 0.
+func quotaOf(cpuMax string) int {
+	fields := strings.Fields(cpuMax)
+	if len(fields) != 2 || fields[0] == "max" {
+		return 0
+	}
+	q, err1 := strconv.Atoi(fields[0])
+	p, err2 := strconv.Atoi(fields[1])
+	if err1 != nil || err2 != nil || p <= 0 {
+		return 0
+	}
+	return q * 100 / p
+}
+
+// nice is this process's nice level from its stat file (the 19th field, counted after the command's closing
+// parenthesis, which may itself hold spaces); 0 when it cannot be read.
+func nice() int {
+	raw, err := os.ReadFile(procSelfStat)
+	if err != nil {
+		return 0
+	}
+	s := string(raw)
+	i := strings.LastIndex(s, ")")
+	if i < 0 {
+		return 0
+	}
+	fields := strings.Fields(s[i+1:])
+	// After the command: state is field 3, so nice (field 19) is index 16.
+	if len(fields) < 17 {
+		return 0
+	}
+	n, _ := strconv.Atoi(fields[16])
+	return n
+}

go/buildcpu/buildcpu_test.go

@@ -0,0 +1,90 @@
+package buildcpu
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+// The node's share as a quota, the threads one step is given for its own module's capacity, and the word the composer
+// hands, in one table (ADR 0553, issue 1806).
+func TestShareQuotaAndThreads(t *testing.T) {
+	for _, c := range []struct {
+		name                  string
+		percent, cores, slots int
+		quota, threads        int
+	}{
+		{"shanks: half of 24, three slots", 50, 24, 3, 1200, 4},
+		{"ace: three quarters of 24, two slots", 75, 24, 2, 1800, 9},
+		{"g14: half of 16, one slot", 50, 16, 1, 800, 8},
+		{"one processor at least", 10, 2, 4, 100, 1},
+		{"no slots counts as one", 100, 4, 0, 400, 4},
+		{"a share out of range is the default", 0, 8, 1, 0, 4},
+	} {
+		if c.quota != 0 {
+			if q := Quota(c.percent, c.cores); q != c.quota {
+				t.Errorf("%s: Quota = %d, want %d", c.name, q, c.quota)
+			}
+		}
+		if th := Threads(c.percent, c.cores, c.slots); th != c.threads {
+			t.Errorf("%s: Threads = %d, want %d", c.name, th, c.threads)
+		}
+	}
+	l := FromWords(func(k string) string { return map[string]string{ShareWord: "75"}[k] }, 2)
+	if l.Percent != 75 || l.From != ShareWord || l.Slots != 2 || l.Threads != Threads(75, runtime.NumCPU(), 2) {
+		t.Errorf("from the word: %+v", l)
+	}
+	// Told nothing usable, a step has no thread limit: nothing in its environment.
+	for _, word := range []string{"", "250", "lots"} {
+		l := FromWords(func(string) string { return word }, 3)
+		if l.Threads != 0 || l.From != "none" || Env(l.Threads) != nil {
+			t.Errorf("share %q: %+v, env %v", word, l, Env(l.Threads))
+		}
+	}
+	if got := Env(3); !reflect.DeepEqual(got, []string{"GOMAXPROCS=3", "UV_THREADPOOL_SIZE=3"}) {
+		t.Errorf("Env = %q", got)
+	}
+}
+
+// What the kernel holds a process to is read from its unit's and its slice's cgroup and its stat file, not assumed.
+func TestReadInForce(t *testing.T) {
+	dir := t.TempDir()
+	cg := filepath.Join(dir, "cg")
+	slice := filepath.Join(cg, "meshyield.slice")
+	unit := filepath.Join(slice, "mesh-build-go-runtime.service")
+	if err := os.MkdirAll(unit, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	for at, files := range map[string]map[string]string{
+		slice: {"cpu.idle": "1\n", "cpu.weight": "0\n", "cpu.max": "1200000 100000\n", "io.weight": "default 1\n"},
+		unit:  {"cpu.idle": "0\n", "cpu.weight": "100\n", "cpu.max": "max 100000\n", "io.weight": "default 100\n"},
+	} {
+		for name, v := range files {
+			if err := os.WriteFile(filepath.Join(at, name), []byte(v), 0o644); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}
+	self := filepath.Join(dir, "cgroup")
+	stat := filepath.Join(dir, "stat")
+	_ = os.WriteFile(self, []byte("0::/meshyield.slice/mesh-build-go-runtime.service\n"), 0o644)
+	// A command with a space and a parenthesis in it, then nice 19 in field 19.
+	_ = os.WriteFile(stat, []byte("42 (mesh (build) go) S 1 42 42 0 -1 4194560 1 0 0 0 0 0 0 0 39 19 8 0 1 2 3\n"), 0o644)
+	cgroupRoot, procSelfCgroup, procSelfStat = cg, self, stat
+	t.Cleanup(func() {
+		cgroupRoot, procSelfCgroup, procSelfStat = "/sys/fs/cgroup", "/proc/self/cgroup", "/proc/self/stat"
+	})
+
+	got := ReadInForce()
+	want := InForce{Nice: 19, Cgroup: "/meshyield.slice/mesh-build-go-runtime.service",
+		Unit: Group{Path: "/meshyield.slice/mesh-build-go-runtime.service", CPUIdle: "0", CPUWeight: "100",
+			CPUMax: "max 100000", IOWeight: "default 100"},
+		Slice: Group{Path: "/meshyield.slice", CPUIdle: "1", CPUWeight: "0", CPUMax: "1200000 100000",
+			IOWeight: "default 1"},
+		Quota: 1200}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("ReadInForce = %+v\nwant %+v", got, want)
+	}
+}

go/buildstep/askrun.go

@@ -34,6 +34,9 @@ type AskSteps struct {
 	// the module's sweep.
 	Release func(workspace string) error
 	Logf    func(format string, args ...any)
+	// Has says whether this node has a need a package's tests declare (delivery.AskNeeds, issue 890); a package needing
+	// what it lacks is not tested here but named in the level's Unmet, for the asker to place. Nil has nothing.
+	Has func(need string) bool
 }
 
 // RunAsk runs ask's job with steps and answers a delivery.BuildAnswer or a delivery.CheckAnswer.
@@ -208,6 +211,9 @@ func (s AskSteps) level(ctx context.Context, job delivery.CheckJob, level string
 		_ = json.Unmarshal(r, &t)
 		return t.Passed, nil
 	}
+	// Every test step of the level runs, also after one that did not pass, so one check names every failing test of the
+	// level and not only the first (issue 1921); the level as a whole passes only when each of its steps did.
+	all := true
 	if s.Digest == nil {
 		// A module with no digest (Node) tests each module directory of the tree, those whose tests changed first.
 		for _, priority := range []bool{true, false} {
@@ -219,23 +225,24 @@ func (s AskSteps) level(ctx context.Context, job delivery.CheckJob, level string
 				if err != nil {
 					return false, fmt.Errorf("the %s level of %s: %w", level, dir, err)
 				}
-				if !passed {
-					return false, nil
-				}
+				all = all && passed
 			}
 		}
-		return true, nil
+		return all, nil
 	}
-	todo, all, keepRunner := s.plan(ctx, job, level, f, runner, withRunner, la)
+	todo, whole, keepRunner := s.plan(ctx, job, level, f, runner, withRunner, la)
 	if !keepRunner {
 		runner = "" // an installed module that ignores the runner judges the level as it judges any other (ADR 0535 §2)
 	}
+	if whole && len(job.Packages) > 0 {
+		todo, whole = job.Packages, false // a placed ask tests its packages alone, whatever the digest said (ADR 0552 §4)
+	}
 	for _, priority := range []bool{true, false} {
 		args := withRunner(map[string]any{"workspace": f.Workspace, "level": level})
 		if job.Run != "" {
 			args["run"] = job.Run
 		}
-		if all {
+		if whole {
 			if priority {
 				continue // nothing to put first: the level runs whole after
 			}
@@ -255,11 +262,9 @@ func (s AskSteps) level(ctx context.Context, job delivery.CheckJob, level string
 		if err != nil {
 			return false, fmt.Errorf("the %s level: %w", level, err)
 		}
-		if !passed {
-			return false, nil
-		}
+		all = all && passed // the packages left still run (issue 1921)
 	}
-	return true, nil
+	return all, nil
 }
 
 // release removes an ask's workspace, saying a failure: the module's sweep removes it later.
@@ -308,9 +313,16 @@ func (s AskSteps) plan(ctx context.Context, job delivery.CheckJob, level string,
 		return nil, true, runner != "" // a digest that names nothing or not the siblings keys no verdict: the level runs whole
 	}
 	la.Digest = &d
+	only := map[string]bool{}
+	for _, p := range job.Packages {
+		only[p] = true
+	}
 	var todo []string
 	for _, pd := range d.Packages {
 		p := pd.Package
+		if len(only) > 0 && !only[p] {
+			continue // a placed ask's other packages were judged by the first ask (ADR 0552 §4)
+		}
 		if job.Kept && s.Kept != nil {
 			tests, found, err := s.Kept(ctx, level, pd.Digest)
 			if err != nil && s.Logf != nil {
@@ -321,6 +333,15 @@ func (s AskSteps) plan(ctx context.Context, job delivery.CheckJob, level string,
 				continue
 			}
 		}
+		if needs := d.NeedsOf(p); len(delivery.Lacks(needs, s.Has)) > 0 {
+			// Its tests would only skip here (issue 890): it is left for a node that has what they need.
+			la.Unmet = append(la.Unmet, delivery.PackageNeeds{Package: p, Needs: needs})
+			if s.Logf != nil {
+				s.Logf("the %s level of %s is left to a node with %s: this node lacks %s", level, p,
+					strings.Join(needs, ", "), strings.Join(delivery.Lacks(needs, s.Has), ", "))
+			}
+			continue
+		}
 		todo = append(todo, p)
 	}
 	return todo, false, false

go/buildstep/askrun_test.go

@@ -20,6 +20,7 @@ type recorder struct {
 	fetch   map[string]any
 	tests   map[string]bool // package or module directory -> passed
 	digests map[string]string
+	needs   []delivery.PackageNeeds
 }
 
 func (r *recorder) steps() AskSteps {
@@ -35,8 +36,10 @@ func (r *recorder) steps() AskSteps {
 		Build: call("build", func(args map[string]any) any {
 			return map[string]any{"digest": "sha256:" + args["artifact"].(string), "reference": "artifact-store://" + args["artifact"].(string)}
 		}),
-		Copy:   call("copy", func(args map[string]any) any { return map[string]any{"digest": "sha256:copied"} }),
-		Digest: call("digest", func(map[string]any) any { return map[string]any{"level": "unit", "packages": r.digests} }),
+		Copy: call("copy", func(args map[string]any) any { return map[string]any{"digest": "sha256:copied"} }),
+		Digest: call("digest", func(map[string]any) any {
+			return map[string]any{"level": "unit", "packages": r.digests, "needs": r.needs}
+		}),
 		Test: call("test", func(args map[string]any) any {
 			passed := true
 			if pkgs, ok := args["packages"].([]string); ok {
@@ -109,9 +112,9 @@ func TestRunAskRefusesAnotherToolchain(t *testing.T) {
 	}
 }
 
-// 1887/A3, A5a, issue 1887 design limit 1: a check ask runs the levels of one check after one fetch: it digests the unit
-// level, takes the kept verdicts, tests the packages whose tests changed first, and stops at the first failure, running
-// no later level.
+// 1887/A3, A5a: a check ask runs the levels of one check after one fetch: it digests the unit level, takes the kept
+// verdicts, tests the packages whose tests changed first, then the rest also after a failure (issue 1921), and runs no
+// level after one that did not pass (ADR 0484 clause 13).
 func TestRunAskChecksTheLevelsOfOneCheck(t *testing.T) {
 	r := &recorder{
 		fetch:   map[string]any{"workspace": "/w", "changed": []string{"pkg/b/b_test.go"}},
@@ -126,7 +129,8 @@ func TestRunAskChecksTheLevelsOfOneCheck(t *testing.T) {
 	got := strings.Join(r.calls, "\n")
 	want := `fetch {"base":"` + runCommit + `","commit":"` + runCommit + `","repository":"novox/x"}
 digest {"level":"unit","workspace":"/w"}
-test {"level":"unit","packages":["x/pkg/b"],"workspace":"/w"}`
+test {"level":"unit","packages":["x/pkg/b"],"workspace":"/w"}
+test {"level":"unit","packages":["x/pkg/a"],"workspace":"/w"}`
 	if got != want {
 		t.Fatalf("calls:\n%s\nwant:\n%s", got, want)
 	}
@@ -135,9 +139,46 @@ test {"level":"unit","packages":["x/pkg/b"],"workspace":"/w"}`
 		t.Fatalf("levels %+v, want the unit level alone", a.Levels)
 	}
 	u := a.Levels[0]
-	if u.Level != delivery.LevelUnit || len(u.Kept) != 1 || u.Kept[0].Package != "x/pkg/k" || u.Kept[0].Tests != 7 || len(u.Tests) != 1 || u.Digest == nil {
+	if u.Level != delivery.LevelUnit || len(u.Kept) != 1 || u.Kept[0].Package != "x/pkg/k" || u.Kept[0].Tests != 7 || len(u.Tests) != 2 || u.Digest == nil {
 		t.Fatalf("the unit level %+v", u)
 	}
+
+	// Issue 890/AC2: a package declaring node-build-node is not tested on a node that lacks it but named unmet, and is
+	// tested on a node that has it.
+	for _, has := range []bool{false, true} {
+		r.calls, r.tests["x/pkg/b"] = nil, true
+		r.needs = []delivery.PackageNeeds{{Package: "x/pkg/a", Needs: []string{delivery.NeedNodeBuildNode}}}
+		steps := r.steps()
+		if has {
+			steps.Has = func(n string) bool { return n == delivery.NeedNodeBuildNode }
+		}
+		out, err := RunAsk(context.Background(), steps, ask(delivery.CheckJob{Levels: []string{delivery.LevelUnit}, Kept: true,
+			Fetch: map[string]any{"repository": "novox/x", "commit": runCommit}}))
+		if err != nil {
+			t.Fatal(err)
+		}
+		u := out.(delivery.CheckAnswer).Levels[0]
+		tested := strings.Contains(strings.Join(r.calls, "\n"), `"x/pkg/a"`)
+		if tested != has || (len(u.Unmet) == 0) == !has || (!has && (u.Unmet[0].Package != "x/pkg/a" || delivery.UnmetNeeds([]delivery.LevelAnswer{u})[0] != delivery.NeedNodeBuildNode)) {
+			t.Fatalf("has %v: tested x/pkg/a %v, unmet %+v, calls %v", has, tested, u.Unmet, r.calls)
+		}
+	}
+	// A placed ask naming its packages tests those alone and takes no other's kept verdict, also when the level would
+	// run whole (ADR 0552 §4).
+	for _, digests := range []map[string]string{r.digests, nil} {
+		r.calls, r.digests = nil, digests
+		steps := r.steps()
+		steps.Has = func(string) bool { return true }
+		out, err := RunAsk(context.Background(), steps, ask(delivery.CheckJob{Levels: []string{delivery.LevelUnit}, Kept: true, Packages: []string{"x/pkg/a"},
+			Fetch: map[string]any{"repository": "novox/x", "commit": runCommit}}))
+		if err != nil {
+			t.Fatal(err)
+		}
+		u := out.(delivery.CheckAnswer).Levels[0]
+		if last := r.calls[len(r.calls)-1]; !strings.HasSuffix(last, `"packages":["x/pkg/a"],"workspace":"/w"}`) || len(u.Kept) != 0 || len(u.Tests) != 1 {
+			t.Fatalf("digests %v: calls %v, kept %+v: want x/pkg/a alone tested, nothing taken kept", digests != nil, r.calls, u.Kept)
+		}
+	}
 }
 
 // ADR 0535 §2, §4: a merge that changes the build module's own code is judged by the candidate's runner: its digest says
@@ -203,3 +244,42 @@ func TestRunAskChecksNodeModulesAndConflicts(t *testing.T) {
 		t.Fatalf("a conflict: %v %v", err, r.calls)
 	}
 }
+
+// Issue 1921: a failure in the packages whose tests changed does not stop the level: the other packages still run, so two
+// failing packages, one changed and one not, are two test results of the one level, and the level does not pass. A Node
+// check runs every module directory after one fails too.
+func TestRunAskRunsEveryPackageAfterAFailure(t *testing.T) {
+	r := &recorder{
+		fetch:   map[string]any{"workspace": "/w", "changed": []string{"pkg/b/b_test.go"}},
+		digests: map[string]string{"x/pkg/a": "d-a", "x/pkg/b": "d-b"},
+		tests:   map[string]bool{"x/pkg/a": false, "x/pkg/b": false},
+	}
+	out, err := RunAsk(context.Background(), r.steps(), ask(delivery.CheckJob{Levels: []string{delivery.LevelIntegration, delivery.LevelUnit},
+		Fetch: map[string]any{"repository": "novox/x", "commit": runCommit}}))
+	if err != nil {
+		t.Fatal(err)
+	}
+	a := out.(delivery.CheckAnswer)
+	if len(a.Levels) != 1 || len(a.Levels[0].Tests) != 2 {
+		t.Fatalf("levels %+v, want the one level with both packages' results", a.Levels)
+	}
+	for i, raw := range a.Levels[0].Tests {
+		var res struct{ Passed bool }
+		if err := json.Unmarshal(raw, &res); err != nil || res.Passed {
+			t.Errorf("result %d %s, want a failure", i, raw)
+		}
+	}
+
+	r = &recorder{fetch: map[string]any{"workspace": "/w", "modules": []string{"a", "b"}, "changed": []string{"b/test/x.test.ts"}},
+		tests: map[string]bool{"a": true, "b": false}}
+	s := r.steps()
+	s.Digest = nil
+	out, err = RunAsk(context.Background(), s, ask(delivery.CheckJob{Levels: []string{delivery.LevelUnit, delivery.LevelIntegration},
+		Fetch: map[string]any{"repository": "novox/x", "commit": runCommit}}))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if a := out.(delivery.CheckAnswer); len(r.calls) != 3 || len(a.Levels) != 1 || len(a.Levels[0].Tests) != 2 {
+		t.Fatalf("calls %v, levels %+v: want both directories of the unit level and no integration level", r.calls, a.Levels)
+	}
+}

go/buildstep/capacity_test.go

@@ -36,3 +36,15 @@ func TestNodeCapacity(t *testing.T) {
 		t.Errorf("a missing file = %d, want 0", got)
 	}
 }
+
+// ADR 0553 §4: a step's threads are the composer's share over the module's own capacity; without the word, none.
+func TestNodeLimits(t *testing.T) {
+	t.Setenv("MESH_BUILD_CPU_SHARE", "")
+	if l := NodeLimits(3); l.Threads != 0 || l.Slots != 3 {
+		t.Errorf("without the word: %+v", l)
+	}
+	t.Setenv("MESH_BUILD_CPU_SHARE", "75")
+	if l := NodeLimits(3); l.Percent != 75 || l.Slots != 3 || l.Threads < 1 {
+		t.Errorf("from the word: %+v", l)
+	}
+}

go/buildstep/cpu.go

@@ -0,0 +1,14 @@
+package buildstep
+
+import (
+	"os"
+
+	"git.novox.be/novox/mesh-sdk/go/buildcpu"
+)
+
+// NodeLimits is what one step of a build module is held to (novox/hq ADR 0553 §4): the node's processor share from the
+// word the composer gives the module (buildcpu.ShareWord), divided by the module's own capacity, own, over the machine's
+// processors. Without the word, no thread limit: Threads is 0.
+func NodeLimits(own int) buildcpu.Limits {
+	return buildcpu.FromWords(os.Getenv, own)
+}

go/buildstep/fetch.go

@@ -71,7 +71,7 @@ func FetchCommit(ctx context.Context, run forgekey.Runner, dir, remote, commit,
 		full := append([]string{"-c", "credential.helper=", "-C", dir}, args...)
 		r := run(ctx, env, "git", full...)
 		if r.Status != 0 || r.Err != "" {
-			return "", fmt.Errorf("git %s: %s", args[0], firstLine(r.Err+" "+r.Stderr))
+			return "", fmt.Errorf("git %s: %s", args[0], forgekey.Said(r.Err+"\n"+r.Stderr))
 		}
 		return r.Stdout, nil
 	}
@@ -128,7 +128,11 @@ func UpdateMirror(ctx context.Context, run forgekey.Runner, mirror, remote, comm
 	git := func(args ...string) error {
 		r := run(ctx, env, "git", append([]string{"-c", "credential.helper="}, args...)...)
 		if r.Status != 0 || r.Err != "" {
-			return fmt.Errorf("git %s: %s", args[0], firstLine(r.Err+" "+r.Stderr))
+			verb := args[0]
+			if verb == "-C" && len(args) > 2 { // the mirror's commands are named by what they do, not by -C
+				verb = args[2]
+			}
+			return fmt.Errorf("git %s: %s", verb, forgekey.Said(r.Err+"\n"+r.Stderr))
 		}
 		return nil
 	}
@@ -190,12 +194,3 @@ func checkFetch(o fetchOptions, dir, remote, commit, ref string) error {
 	}
 	return nil
 }
-
-func firstLine(s string) string {
-	for _, l := range strings.Split(s, "\n") {
-		if l = strings.TrimSpace(l); l != "" {
-			return l
-		}
-	}
-	return ""
-}

go/buildstep/merge.go

@@ -15,6 +15,9 @@ type MergeResult struct {
 	Base, Head, Merge string
 	Conflicts         []string
 	Changed           []string
+	// Programs are the changed files that are compiled programs (ExecutableKind of their first bytes, read in the workspace
+	// at the merge); never nil for a clean merge, so a caller tells none from a module that reports none (issue 1577).
+	Programs []Program
 }
 
 // MergeInto makes, in the workspace dir that FetchCommit left at commit, the merge of commit into the trunk commit
@@ -52,7 +55,7 @@ func MergeInto(ctx context.Context, run forgekey.Runner, dir, remote, base, comm
 		full := append([]string{"-c", "credential.helper=", "-C", dir}, args...)
 		r := run(ctx, env, "git", full...)
 		if r.Status != 0 || r.Err != "" {
-			return "", fmt.Errorf("git %s: %s", args[0], firstLine(r.Err+" "+r.Stderr))
+			return "", fmt.Errorf("git %s: %s", args[0], forgekey.Said(r.Err+"\n"+r.Stderr))
 		}
 		return r.Stdout, nil
 	}
@@ -98,6 +101,16 @@ func MergeInto(ctx context.Context, run forgekey.Runner, dir, remote, base, comm
 		return res, fmt.Errorf("the paths the merge changes cannot be read: %w", err)
 	}
 	res.Changed = strings.Fields(changed)
+	raw, err := git("diff", "--raw", "-z", "--no-renames", "--diff-filter=AM", base, res.Merge)
+	if err != nil {
+		return res, fmt.Errorf("the files the merge adds or modifies cannot be read: %w", err)
+	}
+	res.Programs = programsIn(dir, raw)
+	history, err := historyPrograms(git, base, commit, res.Programs)
+	if err != nil {
+		return res, fmt.Errorf("the commits of the branch cannot be read for compiled programs: %w", err)
+	}
+	res.Programs = append(res.Programs, history...)
 	return res, nil
 }
 

go/buildstep/merge_integration_test.go

@@ -79,6 +79,30 @@ func (r *mergeRig) head(files map[string]string) string {
 	return h
 }
 
+// headThatAddsAndRemoves is head with an earlier commit on the branch that adds a program and a later one that removes it: the
+// branch's tree is clean, its history is not. It answers the head and the earlier commit.
+func (r *mergeRig) headThatAddsAndRemoves(files map[string]string) (head, added string) {
+	realGit(r.t, r.work, "checkout", "-q", "-B", "pr", r.fork)
+	writeFile(r.t, r.work, "gone/prog", "\x7fELF\x02\x01")
+	realGit(r.t, r.work, "add", ".")
+	realGit(r.t, r.work, "commit", "-q", "-m", "oops")
+	added = realGit(r.t, r.work, "rev-parse", "HEAD")
+	realGit(r.t, r.work, "rm", "-q", "gone/prog")
+	return r.head2(files), added
+}
+
+// head2 commits files on the current branch and pushes it as the pull request's head.
+func (r *mergeRig) head2(files map[string]string) string {
+	for n, c := range files {
+		writeFile(r.t, r.work, n, c)
+	}
+	realGit(r.t, r.work, "add", ".")
+	realGit(r.t, r.work, "commit", "-q", "-m", "head")
+	h := realGit(r.t, r.work, "rev-parse", "HEAD")
+	realGit(r.t, r.work, "push", "-q", r.bare, "HEAD:refs/pull/1/head")
+	return h
+}
+
 // advance moves the trunk past the fork point with a commit changing files, pushes it and answers its sha.
 func (r *mergeRig) advance(files map[string]string) string {
 	realGit(r.t, r.work, "checkout", "-q", "-B", "main", r.fork)
@@ -102,7 +126,7 @@ func (r *mergeRig) fetch(head string) {
 // holds both sides' changes.
 func TestMergeIntoACleanMergeAnswersTheMergeCommitAndTheChangedFiles(t *testing.T) {
 	r := newMergeRig(t)
-	head := r.head(map[string]string{"b.txt": "head\n"})
+	head, added := r.headThatAddsAndRemoves(map[string]string{"b.txt": "head\n", "prog": "\x7fELF\x02\x01"})
 	base := r.advance(map[string]string{"a.txt": "one\ntwo\nthree\nfour\n"})
 	r.fetch(head)
 	res, err := MergeInto(context.Background(), forgekey.ExecRunner, r.ws, r.remote, base, head, AllowFileRemote())
@@ -112,8 +136,11 @@ func TestMergeIntoACleanMergeAnswersTheMergeCommitAndTheChangedFiles(t *testing.
 	if res.Base != base || res.Head != head || len(res.Merge) != 40 || res.Merge == base || res.Merge == head || len(res.Conflicts) != 0 {
 		t.Fatalf("result = %+v", res)
 	}
-	if !reflect.DeepEqual(res.Changed, []string{"b.txt"}) {
-		t.Errorf("changed = %v, want only what the head adds to the trunk: b.txt", res.Changed)
+	if !reflect.DeepEqual(res.Changed, []string{"b.txt", "prog"}) {
+		t.Errorf("changed = %v, want only what the head adds to the trunk: b.txt, prog", res.Changed)
+	}
+	if !reflect.DeepEqual(res.Programs, []Program{{"prog", "ELF", ""}, {"gone/prog", "ELF", added}}) { // issue 1577
+		t.Errorf("programs = %v, want the ELF the head adds and the one an earlier commit added and a later one removed", res.Programs)
 	}
 	if at := realGit(t, r.ws, "rev-parse", "HEAD"); at != res.Merge {
 		t.Errorf("the workspace is at %s, not at the merge %s", at, res.Merge)

go/buildstep/mirror_test.go

@@ -104,3 +104,21 @@ func TestUpdateMirrorRefusesBeforeRunning(t *testing.T) {
 		t.Errorf("ran %v", f.calls)
 	}
 }
+
+// The forge's refusal reaches the reason in git's own words: the mirror of a repository its account cannot read said
+// only "git -C: error:" (2026-10-26), since git writes a bare "error:" line before the forge's message.
+func TestUpdateMirrorSaysTheForgesRefusal(t *testing.T) {
+	f := &fakeGit{}
+	f.rule = func(args string) (r forgekey.Ran) {
+		if strings.Contains(args, "fetch") {
+			r.Status = 128
+			r.Stderr = "error: \nerror: User: 22:nox-builder with Key: 30:mesh:ace.mesh-build-go is not authorized to read o/r.\nerror: \nfatal: Could not read from remote repository.\n"
+		}
+		return
+	}
+	err := UpdateMirror(context.Background(), f.run, filepath.Join(t.TempDir(), "m.git"), "ssh://mesh-forge/o/r.git", sha, "")
+	if err == nil || !strings.Contains(err.Error(), "nox-builder with Key: 30:mesh:ace.mesh-build-go is not authorized to read o/r.") ||
+		!strings.Contains(err.Error(), "Could not read from remote repository") || !strings.HasPrefix(err.Error(), "git fetch: ") {
+		t.Errorf("err = %v", err)
+	}
+}

go/buildstep/programs.go

@@ -0,0 +1,115 @@
+package buildstep
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Program is a changed file whose first bytes are an executable binary: a compiled program, which is build output and not
+// source (novox/hq issue 1577: `go build` in a module's folder writes one beside go.mod, and `git add -A` takes it).
+type Program struct {
+	Path string `json:"path"`
+	Kind string `json:"kind"` // ELF, Mach-O or PE
+	// Commit is set for a program a commit of the branch added and a later one removed (or replaced): the merge's tree is clean,
+	// but the merge commit carries the blob into the trunk's history for good. Empty for a program the merge's tree holds.
+	Commit string `json:"commit,omitempty"`
+}
+
+// ExecutableKind says what executable format the first bytes of a file are, or "" when they are none. A PE needs its header
+// ("PE\0\0" at the offset in bytes 0x3c) so a text starting with "MZ" is not one; a fat Mach-O (0xCAFEBABE) is told from a
+// Java class by its architecture count (bytes 4 to 7, fewer than 0x20; a class has its version there).
+func ExecutableKind(head []byte) string {
+	switch {
+	case bytes.HasPrefix(head, []byte("\x7fELF")):
+		return "ELF"
+	case bytes.HasPrefix(head, []byte("MZ")):
+		if len(head) >= 0x40 {
+			off := int(head[0x3c]) | int(head[0x3d])<<8 | int(head[0x3e])<<16 | int(head[0x3f])<<24
+			if off >= 0 && off+4 <= len(head) && bytes.Equal(head[off:off+4], []byte("PE\x00\x00")) {
+				return "PE"
+			}
+		}
+	case bytes.HasPrefix(head, []byte{0xcf, 0xfa, 0xed, 0xfe}), bytes.HasPrefix(head, []byte{0xce, 0xfa, 0xed, 0xfe}),
+		bytes.HasPrefix(head, []byte{0xfe, 0xed, 0xfa, 0xcf}), bytes.HasPrefix(head, []byte{0xfe, 0xed, 0xfa, 0xce}),
+		bytes.HasPrefix(head, []byte{0xca, 0xfe, 0xba, 0xbe}) && len(head) >= 8 && head[4] == 0 && head[5] == 0 && head[6] == 0 && head[7] < 0x20:
+		return "Mach-O"
+	}
+	return ""
+}
+
+// programHeadSize is how many bytes of a file are read to tell its format: enough for a PE header at its usual offsets.
+const programHeadSize = 0x100
+
+// historyPrograms names the compiled programs that a commit of base..head added or modified and the merge's tree no longer
+// holds at that path (those it holds are in final already): each with the commit that added it. git is the merge's git runner.
+func historyPrograms(git func(args ...string) (string, error), base, head string, final []Program) ([]Program, error) {
+	revs, err := git("rev-list", "--no-merges", "--reverse", base+".."+head)
+	if err != nil {
+		return nil, err
+	}
+	held := map[string]bool{}
+	for _, p := range final {
+		held[p.Path] = true
+	}
+	out, seen := []Program{}, map[string]bool{}
+	for _, c := range strings.Fields(revs) {
+		raw, err := git("diff-tree", "-r", "-z", "--no-commit-id", "--no-renames", "--root", "--diff-filter=AM", c)
+		if err != nil {
+			return nil, err
+		}
+		f := strings.Split(raw, "\x00")
+		for i := 0; i+1 < len(f); i += 2 {
+			meta := strings.Fields(strings.TrimPrefix(f[i], ":"))
+			if len(meta) < 4 || (meta[1] != "100644" && meta[1] != "100755") || held[f[i+1]] || seen[meta[3]] {
+				continue
+			}
+			seen[meta[3]] = true
+			blob, err := git("cat-file", "blob", meta[3])
+			if err != nil {
+				return nil, err
+			}
+			head := []byte(blob)
+			if len(head) > programHeadSize {
+				head = head[:programHeadSize]
+			}
+			if k := ExecutableKind(head); k != "" {
+				out = append(out, Program{Path: f[i+1], Kind: k, Commit: c})
+			}
+		}
+	}
+	return out, nil
+}
+
+// programsIn reads the output of `git diff --raw -z --no-renames --diff-filter=AM` (":<old mode> <new mode> <old sha> <new
+// sha> <status>\0<path>\0" per file) and names each added or modified regular file of the tree dir that is a compiled
+// program, from its first bytes read locally. A symlink (mode 120000) and a submodule (160000) are not read. It never
+// answers nil, so a caller can tell no programs from none reported.
+func programsIn(dir, raw string) []Program {
+	out := []Program{}
+	f := strings.Split(raw, "\x00")
+	for i := 0; i+1 < len(f); i += 2 {
+		meta := strings.Fields(strings.TrimPrefix(f[i], ":"))
+		if len(meta) < 2 || (meta[1] != "100644" && meta[1] != "100755") {
+			continue
+		}
+		p := f[i+1]
+		full := filepath.Join(dir, filepath.FromSlash(p))
+		if st, err := os.Lstat(full); err != nil || !st.Mode().IsRegular() {
+			continue
+		}
+		fh, err := os.Open(full)
+		if err != nil {
+			continue
+		}
+		head := make([]byte, programHeadSize)
+		n, _ := io.ReadFull(fh, head)
+		fh.Close()
+		if k := ExecutableKind(head[:n]); k != "" {
+			out = append(out, Program{Path: p, Kind: k})
+		}
+	}
+	return out
+}

go/buildstep/programs_test.go

@@ -0,0 +1,72 @@
+package buildstep
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+func pe(offset int, magic string) []byte {
+	b := make([]byte, 0x100)
+	copy(b, "MZ")
+	b[0x3c] = byte(offset)
+	copy(b[offset:], magic)
+	return b
+}
+
+func TestExecutableKindTellsProgramsFromText(t *testing.T) { // issue 1577
+	for _, c := range []struct {
+		name string
+		head []byte
+		want string
+	}{
+		{"elf", []byte("\x7fELF\x02\x01\x01"), "ELF"},
+		{"mach-o 64", []byte{0xcf, 0xfa, 0xed, 0xfe, 7, 0, 0, 1}, "Mach-O"},
+		{"mach-o 32 big", []byte{0xfe, 0xed, 0xfa, 0xce, 0, 0, 0, 7}, "Mach-O"},
+		{"fat mach-o", []byte{0xca, 0xfe, 0xba, 0xbe, 0, 0, 0, 2}, "Mach-O"},
+		{"java class", []byte{0xca, 0xfe, 0xba, 0xbe, 0, 0, 0, 0x34}, ""},
+		{"pe", pe(0x80, "PE\x00\x00"), "PE"},
+		{"mz text", []byte("MZ is a text file starting with two letters"), ""},
+		{"mz without a pe header", pe(0x80, "XX\x00\x00"), ""},
+		{"text", []byte("package main"), ""},
+		{"empty", nil, ""},
+	} {
+		if got := ExecutableKind(c.head); got != c.want {
+			t.Errorf("%s: kind = %q, want %q", c.name, got, c.want)
+		}
+	}
+}
+
+func TestProgramsInNamesTheAddedAndModifiedRegularFilesThatArePrograms(t *testing.T) { // issue 1577
+	dir := t.TempDir()
+	write := func(name string, b []byte) {
+		if err := os.MkdirAll(filepath.Dir(filepath.Join(dir, name)), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(dir, name), b, 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	write("m/prog", []byte("\x7fELF\x02\x01"))
+	write("m/notes", []byte("plain text"))
+	write("m/mac", []byte{0xcf, 0xfa, 0xed, 0xfe, 7, 0, 0, 1})
+	if err := os.Symlink("prog", filepath.Join(dir, "m/link")); err != nil {
+		t.Fatal(err)
+	}
+	line := func(mode, path string) string { return ":000000 " + mode + " 0000 1111 A\x00" + path + "\x00" }
+	for _, c := range []struct {
+		name, raw string
+		want      []Program
+	}{
+		{"none", "", []Program{}},
+		{"a program and a text", line("100755", "m/prog") + line("100644", "m/notes"), []Program{{"m/prog", "ELF", ""}}},
+		{"two programs", line("100644", "m/prog") + line("100755", "m/mac"), []Program{{"m/prog", "ELF", ""}, {"m/mac", "Mach-O", ""}}},
+		{"a symlink and a submodule are not read", line("120000", "m/link") + line("160000", "m/sub"), []Program{}},
+		{"a path the tree lacks", line("100644", "m/gone"), []Program{}},
+	} {
+		if got := programsIn(dir, c.raw); !reflect.DeepEqual(got, c.want) {
+			t.Errorf("%s: programs = %v, want %v", c.name, got, c.want)
+		}
+	}
+}

go/buildstep/pull.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"sort"
+	"strings"
 	"sync"
 	"time"
 
@@ -76,6 +77,11 @@ type Puller struct {
 	// for this node, and wakes the puller on each change (watchCapacity): WatchConfigServed in a module, a test's own
 	// double. Until it hands a value the puller judges by Capacity.
 	WatchConfig func(key string, handle func(stdio.ProvisionChange) error) error
+	// Has says whether this node has a need an ask names (delivery.AskNeeds, issue 890). An ask needing what it lacks is
+	// declined: its step ends refused as declined (delivery.StepDeclined), the message is dropped for its asker to put
+	// again, and the worker it came from is not looked at again until the next pull's wait, so a node lacking the need
+	// does not take the asker's next copy at once. Nil has nothing.
+	Has func(need string) bool
 
 	mu      sync.Mutex
 	inHand  int
@@ -86,6 +92,9 @@ type Puller struct {
 	// watched is the capacity the config watch handed last, used in place of Capacity once hasWatched.
 	watched    int
 	hasWatched bool
+	// declined are the kinds whose worker handed an ask this node declined, left out of the pulls without a wait until
+	// the next pull's wait ends.
+	declined map[string]bool
 }
 
 func (p *Puller) init() {
@@ -283,17 +292,59 @@ func (p *Puller) Pull(ctx context.Context) error {
 
 // next is one ask from the workers in their order: one already waiting on delivery, check or recheck, and when none
 // waits, a pull of the delivery worker that waits for one.
+//
+// A kind whose worker handed an ask this node declined is left out until that wait ended (issue 890): the pull's own
+// wait, no timer of its own.
 func (p *Puller) next(ctx context.Context, wait time.Duration) (*Pulled, error) {
+	p.mu.Lock()
+	declined := p.declined
+	p.mu.Unlock()
 	for _, kind := range delivery.AskKinds {
+		if declined[kind] {
+			continue
+		}
 		msg, err := p.Source.Next(ctx, kind, 0)
 		if err != nil || msg != nil {
 			return withKind(msg, kind), err
 		}
 	}
 	msg, err := p.Source.Next(ctx, delivery.AskDelivery, wait)
+	p.mu.Lock()
+	p.declined = nil
+	p.mu.Unlock()
 	return withKind(msg, delivery.AskDelivery), err
 }
 
+// decline ends the step of an ask this node lacks a need of, refused as declined with what it lacks, and drops the
+// message: the asker puts the ask again under a new id (issue 890). A message whose decline cannot be written is handed
+// back, as one whose start cannot be.
+func (p *Puller) decline(msg *Pulled, ask delivery.StepAsk, lacks []string) {
+	step, key, err := begin(p.Put, p.Node, ask.Kind+" ask", ask.ID, AskWhat(ask))
+	if err == nil {
+		why := Refuse("the ask %s needs %s, and %s lacks %s: it is left to a node that has it", ask.ID,
+			strings.Join(ask.Needs, ", "), p.Node, strings.Join(lacks, ", "))
+		step.Ended = now().UTC()
+		step.State, step.Reason = delivery.StepRefused, why.Error()
+		step.Result, err = json.Marshal(delivery.StepDeclined{Declined: true, Needs: ask.Needs, Lacks: lacks})
+		if err == nil {
+			err = writeEnd(p.Put, key, step)
+		}
+	}
+	if err != nil {
+		p.logf("the ask %s cannot be declined on %s, so it is given back: %v", ask.ID, p.Node, err)
+		_ = msg.Nak()
+		return
+	}
+	p.logf("the ask %s is declined on %s: it needs %s, and this node lacks %s", ask.ID, p.Node, strings.Join(ask.Needs, ", "), strings.Join(lacks, ", "))
+	_ = msg.Term()
+	p.mu.Lock()
+	if p.declined == nil {
+		p.declined = map[string]bool{}
+	}
+	p.declined[msg.Kind] = true
+	p.mu.Unlock()
+}
+
 func withKind(msg *Pulled, kind string) *Pulled {
 	if msg != nil {
 		msg.Kind = kind
@@ -314,7 +365,11 @@ func (p *Puller) take(ctx context.Context, msg *Pulled) {
 		_ = msg.Term()
 		return
 	}
-	step, key, err := begin(p.Put, p.Node, ask.Kind+" ask", ask.ID)
+	if lacks := delivery.Lacks(ask.Needs, p.Has); len(lacks) > 0 {
+		p.decline(msg, ask, lacks)
+		return
+	}
+	step, key, err := begin(p.Put, p.Node, ask.Kind+" ask", ask.ID, AskWhat(ask))
 	if err != nil {
 		p.logf("the ask %s cannot start on %s: %v", ask.ID, p.Node, err)
 		_ = msg.Nak()

go/buildstep/pull_test.go

@@ -137,23 +137,42 @@ func TestPullHoldsAtMostItsCapacity(t *testing.T) {
 	waitFor(t, "all acked", func() bool { a, _, _ := src.Fates(); return len(a) == 3 })
 }
 
-// An ask that is not one, or not this seat's, is dropped and runs nowhere.
+// An ask that is not one, or not this seat's, is dropped and runs nowhere. And issue 890/AC1: a check ask needing
+// node-build-node is declined on a node that lacks it (its step refused as declined, naming what it lacks, the message
+// dropped for the asker to put again), and runs on a node that has it.
 func TestPullDropsWhatIsNoAsk(t *testing.T) {
 	src, st := NewFakeAsks(), newSteps()
 	src.Publish(delivery.AskDelivery, []byte(`{"v":1}`))
 	other := testAsk(delivery.AskDelivery)
 	other.Language = delivery.AskNode
 	_ = src.PublishAsk(other)
+	placed := testAsk(delivery.AskCheck)
+	placed.Needs = []string{delivery.NeedNodeBuildNode}
+	if err := src.PublishAsk(placed); err != nil {
+		t.Fatal(err)
+	}
 	ran := false
-	p := &Puller{Source: src, Language: delivery.AskGo, Node: "shanks", Put: st.put, Capacity: func() int { return 1 },
+	p := &Puller{Source: src, Language: delivery.AskGo, Node: "ace", Put: st.put, Capacity: func() int { return 1 },
 		PullWait: 10 * time.Millisecond, Run: func(ctx context.Context, a delivery.StepAsk) (any, error) { ran = true; return nil, nil }}
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	go p.Pull(ctx)
-	waitFor(t, "two termed", func() bool { _, tm, _ := src.Fates(); return len(tm) == 2 })
+	waitFor(t, "three termed", func() bool { _, tm, _ := src.Fates(); return len(tm) == 3 })
 	if ran {
-		t.Fatal("a wrong ask ran")
+		t.Fatal("a wrong or a declined ask ran")
 	}
+	key, _ := delivery.AskStepKey("ace", placed.ID)
+	s, _ := st.get(key)
+	if d, ok := delivery.DeclinedOf(s); !ok || len(d.Lacks) != 1 || d.Lacks[0] != delivery.NeedNodeBuildNode || !strings.Contains(s.Reason, "lacks node-build-node") {
+		t.Fatalf("the declined step = %+v", s)
+	}
+	has, hasSteps := NewFakeAsks(), newSteps()
+	_ = has.PublishAsk(placed)
+	q := &Puller{Source: has, Language: delivery.AskGo, Node: "g14", Put: hasSteps.put, Capacity: func() int { return 1 },
+		PullWait: 10 * time.Millisecond, Has: func(n string) bool { return n == delivery.NeedNodeBuildNode },
+		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) { return nil, nil }}
+	go q.Pull(ctx)
+	waitFor(t, "the placed ask acked where its need is met", func() bool { a, _, _ := has.Fates(); return len(a) == 1 })
 }
 
 // load reads the recorded steps state's raw values: the pause key is not a step, so it is kept apart.

go/buildstep/stale.go

@@ -0,0 +1,272 @@
+package buildstep
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **A step left running** (novox/hq issue 1890, note 5). A build module that stops while a step runs leaves its key in
+// state running for good: nothing else writes that key's end, and the stream's redelivery only rewrites it when the same
+// ask comes back. At its start a module ends the steps its node left running before the process began (EndStale), and
+// its step-end tool ends one by hand (EndOne).
+
+// RestartReason is why a step a previous process left running is ended.
+const RestartReason = "the build module restarted while it ran"
+
+// Boot is when this process began. A step started at or after it belongs to this process, which may still run it, so
+// EndOne refuses it.
+var Boot = time.Now()
+
+// Scan reads and writes a steps state with its revisions: its keys, a key's stored value and revision (nil and 0 for
+// none), and a write that lands only while the key is still at the revision read (KeptState.Update), failing with
+// stdio.ErrChanged when another writer was first.
+type Scan struct {
+	Keys   func() ([]string, error)
+	Get    func(key string) (json.RawMessage, uint64, error)
+	Update func(key string, value any, revision uint64) (uint64, error)
+}
+
+// ScanOf is the Scan of a state the process keeps.
+func ScanOf(s stdio.KeptState) Scan {
+	return Scan{Keys: s.Keys, Update: s.Update, Get: func(key string) (json.RawMessage, uint64, error) {
+		e, err := s.Get(key)
+		if err != nil || e == nil {
+			return nil, 0, err
+		}
+		return e.Value, e.Revision, nil
+	}}
+}
+
+// isAsk says a step is a pulled ask's: its key is <node>.<ask id> and its tool is "<kind> ask" (a hand-started step
+// has the tool's name). An ask's key is the stream's to settle, never a restart's: the puller leaves an ask it was
+// running unacknowledged so the stream redelivers it, and the asker's wait takes the first end it reads on the key.
+// Only once the asker's bound has passed (delivery.StepBound) is the key nobody's, and then it is ended.
+func isAsk(key string, s delivery.Step) bool {
+	_, _, err := delivery.ParseAskStepKey(key)
+	return err == nil && strings.HasSuffix(s.Tool, " ask")
+}
+
+// AskWhat says what an ask is, in one line: its kind, and its repository, head and levels, or its module and
+// fingerprint.
+func AskWhat(a delivery.StepAsk) string {
+	short := func(s string) string {
+		if len(s) > 12 {
+			return s[:12]
+		}
+		return s
+	}
+	str := func(m map[string]any, k string) string { v, _ := m[k].(string); return v }
+	parts := []string{a.Kind + " ask"}
+	switch {
+	case a.Check != nil:
+		parts = append(parts, str(a.Check.Fetch, "repository")+"@"+short(str(a.Check.Fetch, "commit")), "levels "+strings.Join(a.Check.Levels, ","))
+		if a.Check.Run != "" {
+			parts = append(parts, "run "+a.Check.Run)
+		}
+	case a.Build != nil:
+		parts = append(parts, "module "+a.Build.Module)
+		if r := str(a.Build.Fetch, "repository"); r != "" {
+			parts = append(parts, r+"@"+short(str(a.Build.Fetch, "commit")))
+		}
+		if a.Build.FP != "" {
+			parts = append(parts, "fp "+short(a.Build.FP))
+		}
+	case a.Compose != nil:
+		parts = append(parts, "compose", str(a.Compose.Fetch, "repository")+"@"+short(str(a.Compose.Fetch, "commit")))
+	}
+	return strings.Join(parts, ", ")
+}
+
+// endRunning writes step ended failed with why, only while its key is still at revision.
+func endRunning(scan Scan, key string, step delivery.Step, revision uint64, why string) error {
+	step.State, step.Reason, step.Ended, step.Result = delivery.StepFailed, why, now().UTC(), nil
+	raw, err := delivery.EncodeStep(step)
+	if err != nil {
+		return err
+	}
+	_, err = scan.Update(key, json.RawMessage(raw), revision)
+	return err
+}
+
+// EndStale ends this node's steps that are running and started before `before` (the start of this process) as failed
+// with RestartReason, and answers their ids. Only keys of node are read; a value that is no step is left alone. A step
+// of a pulled ask is left to the stream's redelivery (isAsk) until its start is older than delivery.StepBound: its asker
+// stopped waiting then, whether the stream gave it to another node or gave it up, and it is ended as failed, "past the
+// step bound: its asker stopped waiting at <time>". A key written by another writer since it was read
+// (a redelivered ask's start, a real end) is skipped.
+func EndStale(scan Scan, node string, before time.Time, logf func(string, ...any)) ([]string, error) {
+	keys, err := scan.Keys()
+	if err != nil {
+		return nil, fmt.Errorf("buildstep: listing the steps of %s: %w", node, err)
+	}
+	var ended []string
+	for _, k := range keys {
+		n, _, perr := delivery.ParseStepKey(k)
+		if perr != nil || n != node {
+			continue
+		}
+		raw, rev, err := scan.Get(k)
+		if err != nil {
+			return ended, fmt.Errorf("buildstep: reading the step %s: %w", k, err)
+		}
+		if len(raw) == 0 {
+			continue
+		}
+		step, err := delivery.DecodeStep(raw)
+		if err != nil || step.State != delivery.StepRunning {
+			continue
+		}
+		why := RestartReason
+		if isAsk(k, step) {
+			if !step.Started.Add(delivery.StepBound).Before(now()) {
+				continue
+			}
+			why = "past the step bound: its asker stopped waiting at " + step.Started.Add(delivery.StepBound).UTC().Format("2006-01-02T15:04:05Z")
+		} else if !step.Started.Before(before) {
+			continue
+		}
+		if err := endRunning(scan, k, step, rev, why); err != nil {
+			if errors.Is(err, stdio.ErrChanged) {
+				continue
+			}
+			return ended, fmt.Errorf("buildstep: ending the step %s: %w", k, err)
+		}
+		if logf != nil {
+			logf("the step %s (%s) was left running and is ended: %s", k, step.Tool, why)
+		}
+		ended = append(ended, step.ID)
+	}
+	return ended, nil
+}
+
+// EndOne ends this node's running step id (or the key <node>.<id>) as failed with why. A step that is not running is
+// refused, and so is one started since this process began (Boot: it may still run, whether a pulled ask or a step a
+// tool started), one live reports as held, and one whose key changed since it was read.
+func EndOne(scan Scan, node, id, why string, live func(id string) bool) (delivery.Step, error) {
+	id = strings.TrimSpace(id)
+	if n, rest, ok := strings.Cut(id, "."); ok {
+		if n != node {
+			return delivery.Step{}, fmt.Errorf("the step %q is of node %q, this module runs on %q", id, n, node)
+		}
+		id = rest
+	}
+	if strings.TrimSpace(why) == "" {
+		return delivery.Step{}, fmt.Errorf("say why the step is ended (why)")
+	}
+	key, err := delivery.StepKey(node, id)
+	if err != nil {
+		return delivery.Step{}, err
+	}
+	raw, rev, err := scan.Get(key)
+	if err != nil {
+		return delivery.Step{}, err
+	}
+	if len(raw) == 0 {
+		return delivery.Step{}, fmt.Errorf("no step %s in the steps state", key)
+	}
+	step, err := delivery.DecodeStep(raw)
+	if err != nil {
+		return delivery.Step{}, err
+	}
+	if step.State != delivery.StepRunning {
+		return delivery.Step{}, fmt.Errorf("the step %s is %s, not running", key, step.State)
+	}
+	if !step.Started.Before(Boot) || (live != nil && live(id)) {
+		return delivery.Step{}, fmt.Errorf("the step %s was started by this process and may run now; only a step a previous process left is ended", key)
+	}
+	if err := endRunning(scan, key, step, rev, why); err != nil {
+		if errors.Is(err, stdio.ErrChanged) {
+			return delivery.Step{}, fmt.Errorf("the step %s changed while it was being ended; read it again", key)
+		}
+		return delivery.Step{}, err
+	}
+	step.State, step.Reason = delivery.StepFailed, why
+	return step, nil
+}
+
+// StepEndTool is the module's step-end tool, named name (build_go_step_end): it ends one step left running, with a
+// reason, refusing one this process started. p may be nil.
+func StepEndTool(name string, node string, scan Scan, p *Puller) stdio.Tool {
+	return stdio.Tool{Name: name,
+		Description: "End one step of this machine that is stuck in state running (for instance left by a restart of the module) " +
+			"as failed, with the reason given; its asker then sees it over, so ending an ask still in its stream fails its asker. " +
+			"A step not running, or one this process started, is refused. " +
+			"id is the step id or the key <node>.<id>.",
+		Input: map[string]any{"type": "object", "required": []string{"id", "why"}, "properties": map[string]any{
+			"id":  map[string]any{"type": "string", "description": "the step id, or the key <node>.<id>"},
+			"why": map[string]any{"type": "string", "description": "why it is ended; it becomes the step's reason"}}},
+		Run: func(args map[string]any) (any, error) {
+			id, _ := args["id"].(string)
+			why, _ := args["why"].(string)
+			var live func(string) bool
+			if p != nil {
+				live = func(id string) bool {
+					for _, r := range p.Running() {
+						if r.ID == id {
+							return true
+						}
+					}
+					return false
+				}
+			}
+			return EndOne(scan, node, id, why, live)
+		}}
+}
+
+// StaleAttempts and StaleRetry bound EndStaleAtStart's tries: the steps state is readable once the runtime serves.
+var (
+	StaleAttempts = 6
+	StaleRetry    = 5 * time.Second
+)
+
+// EndStaleAtStart is what a build module runs once at its start, in a goroutine: it waits for the runtime to serve,
+// then ends this node's steps left running before `before` (EndStale), trying again when the state cannot be read yet.
+// A step this process starts is never one of them: it starts after `before`.
+func EndStaleAtStart(ctx context.Context, scan Scan, node string, before time.Time, logf func(string, ...any)) {
+	select {
+	case <-ctx.Done():
+		return
+	case <-stdio.Served():
+	}
+	for attempt := 1; ; attempt++ {
+		ended, err := EndStale(scan, node, before, logf)
+		if err == nil {
+			if logf != nil {
+				logf("%d steps of %s left running by a previous process ended", len(ended), node)
+			}
+			return
+		}
+		if logf != nil {
+			logf("ending the steps left running (try %d of %d): %v", attempt, StaleAttempts, err)
+		}
+		if attempt >= StaleAttempts {
+			return
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(StaleRetry):
+		}
+	}
+}
+
+// EndStaleRound is EndStale as the module's periodic round runs it: at once, and only when the runtime serves (a round
+// before that is skipped, the start's EndStaleAtStart and the next round cover it). It ends the steps a previous
+// process left and the asks past delivery.StepBound.
+func EndStaleRound(scan Scan, node string, logf func(string, ...any)) {
+	select {
+	case <-stdio.Served():
+	default:
+		return
+	}
+	if _, err := EndStale(scan, node, Boot, logf); err != nil && logf != nil {
+		logf("ending the steps left running: %v", err)
+	}
+}

go/buildstep/stale_test.go

@@ -0,0 +1,131 @@
+package buildstep
+
+import (
+	"encoding/json"
+	stdio "git.novox.be/novox/mesh-sdk/go"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// scanOf is the steps a keys double holds, last value per key, its revision the count of its puts; a write through
+// Update lands only at the revision read, as the state's does. race, when set, runs once before the next Update's check.
+func scanOf(k *keys, race func(key string)) Scan {
+	return Scan{
+		Keys: func() ([]string, error) {
+			k.mu.Lock()
+			defer k.mu.Unlock()
+			var out []string
+			for key := range k.puts {
+				out = append(out, key)
+			}
+			return out, nil
+		},
+		Get: func(key string) (json.RawMessage, uint64, error) {
+			k.mu.Lock()
+			defer k.mu.Unlock()
+			s, ok := k.puts[key]
+			if !ok {
+				return nil, 0, nil
+			}
+			raw, err := delivery.EncodeStep(s[len(s)-1])
+			return raw, uint64(len(s)), err
+		},
+		Update: func(key string, value any, revision uint64) (uint64, error) {
+			if race != nil {
+				race(key)
+			}
+			k.mu.Lock()
+			n := uint64(len(k.puts[key]))
+			k.mu.Unlock()
+			if n != revision {
+				return 0, stdio.ErrChanged
+			}
+			return k.put(key, value)
+		},
+	}
+}
+
+// 1890: EndStale ends only this node's hand-started steps left running before the process began and the asks past the
+// step bound (a younger ask is the stream's to redeliver), and never a key written meanwhile; EndOne ends one by hand, never one this process started.
+func TestEndStaleAndEndOne(t *testing.T) {
+	k := newKeys()
+	boot := time.Now()
+	oldBoot := Boot
+	Boot = boot
+	defer func() { Boot = oldBoot }()
+	put := func(node, id, tool, state string, started time.Time) {
+		key, _ := delivery.StepKey(node, id)
+		_, _ = k.put(key, json.RawMessage(mustStep(t, delivery.Step{ID: id, Tool: tool, Node: node, State: state, Started: started})))
+	}
+	put("ace", "old1", "build_go_fetch", delivery.StepRunning, boot.Add(-time.Hour))
+	put("ace", "mjk3l9x0abcdef", "check ask", delivery.StepRunning, boot.Add(-time.Hour))
+	put("ace", "mjk3l9x0abcdee", "check ask", delivery.StepRunning, time.Now().Add(-5*time.Minute))
+	put("ace", "raced1", "build_go_test", delivery.StepRunning, boot.Add(-time.Hour))
+	put("ace", "new1", "build_go_fetch", delivery.StepRunning, boot.Add(time.Second))
+	put("ace", "done1", "build_go_fetch", delivery.StepPassed, boot.Add(-time.Hour))
+	put("g14", "other1", "build_go_fetch", delivery.StepRunning, boot.Add(-time.Hour))
+	// raced1 is ended by its own run between the read and the write.
+	raced := false
+	scan := scanOf(k, func(key string) {
+		if key == "ace.raced1" && !raced {
+			raced = true
+			put("ace", "raced1", "build_go_test", delivery.StepPassed, boot.Add(-time.Hour))
+		}
+	})
+	ended, err := EndStale(scan, "ace", boot, nil)
+	if err != nil || len(ended) != 2 || ended[0] == ended[1] {
+		t.Fatalf("ended %v, %v", ended, err)
+	}
+	if s := k.last("ace.old1"); s.State != delivery.StepFailed || s.Reason != RestartReason || s.Ended.IsZero() {
+		t.Errorf("old1 = %+v", s)
+	}
+	if s := k.last("ace.mjk3l9x0abcdef"); s.State != delivery.StepFailed || !strings.HasPrefix(s.Reason, "past the step bound: its asker stopped waiting at ") {
+		t.Errorf("the old ask = %+v", s)
+	}
+	for key, state := range map[string]string{"ace.mjk3l9x0abcdee": delivery.StepRunning, "ace.raced1": delivery.StepPassed, "ace.new1": delivery.StepRunning, "ace.done1": delivery.StepPassed, "g14.other1": delivery.StepRunning} {
+		if s := k.last(key); s.State != state {
+			t.Errorf("%s = %s, want %s", key, s.State, state)
+		}
+	}
+	// EndOne: refuses without why, a held step, one started by this process (a pulled ask or a step tool's), a step not
+	// running and another node's; ends a step a previous process left.
+	for _, c := range []struct{ id, why string }{{"old1", ""}, {"new1", "stuck"}, {"done1", "x"}, {"g14.other1", "x"}} {
+		if _, err := EndOne(scan, "ace", c.id, c.why, nil); err == nil {
+			t.Errorf("ended %s with why %q", c.id, c.why)
+		}
+	}
+	put("ace", "old2", "build_go_fetch", delivery.StepRunning, boot.Add(-time.Hour))
+	if _, err := EndOne(scan, "ace", "old2", "x", func(string) bool { return true }); err == nil {
+		t.Error("ended a held step")
+	}
+	if _, err := EndOne(scan, "ace", "ace.old2", "stuck for good", nil); err != nil {
+		t.Fatal(err)
+	}
+	if s := k.last("ace.old2"); s.State != delivery.StepFailed || s.Reason != "stuck for good" {
+		t.Errorf("old2 = %+v", s)
+	}
+}
+
+func mustStep(t *testing.T, s delivery.Step) []byte {
+	t.Helper()
+	raw, err := delivery.EncodeStep(s)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return raw
+}
+
+// 1890: AskWhat names the repository, head and levels of a check ask and the module of a build ask.
+func TestAskWhat(t *testing.T) {
+	check := delivery.StepAsk{Kind: "check", Check: &delivery.CheckJob{Fetch: map[string]any{"repository": "novox/mesh-sdk", "commit": "0123456789abcdef0123"}, Levels: []string{"unit", "integration"}}}
+	if got, want := AskWhat(check), "check ask, novox/mesh-sdk@0123456789ab, levels unit,integration"; got != want {
+		t.Errorf("check = %q", got)
+	}
+	build := delivery.StepAsk{Kind: "delivery", Build: &delivery.BuildJob{Module: "mesh-x", FP: "abcdef0123456789"}}
+	if got, want := AskWhat(build), "delivery ask, module mesh-x, fp abcdef012345"; got != want {
+		t.Errorf("build = %q", got)
+	}
+}

go/buildstep/step.go

@@ -43,7 +43,7 @@ func NewID() string {
 // the error's text, or refused when the error is a *Refusal; a panic in run ends the step failed, naming it, and
 // the process goes on. If the running write fails, nothing was started and Start answers the error.
 func Start(ctx context.Context, put Put, node, tool string, run func(ctx context.Context) (result any, err error)) (string, error) {
-	step, key, err := begin(put, node, tool, NewID())
+	step, key, err := begin(put, node, tool, NewID(), "")
 	if err != nil {
 		return "", err
 	}
@@ -52,8 +52,8 @@ func Start(ctx context.Context, put Put, node, tool string, run func(ctx context
 }
 
 // begin writes the step running under id.
-func begin(put Put, node, tool, id string) (delivery.Step, string, error) {
-	step := delivery.Step{ID: id, Tool: tool, Node: node, State: delivery.StepRunning, Started: now().UTC()}
+func begin(put Put, node, tool, id, what string) (delivery.Step, string, error) {
+	step := delivery.Step{ID: id, Tool: tool, Node: node, State: delivery.StepRunning, Started: now().UTC(), What: what}
 	key, err := delivery.StepKey(node, step.ID)
 	if err != nil {
 		return delivery.Step{}, "", err

go/buildstep/trees.go

@@ -36,7 +36,7 @@ var lockFiles = []string{"go.sum", "package-lock.json"}
 func ModuleTrees(ctx context.Context, run forgekey.Runner, env []string, dir, commit string) (map[string]ModuleTree, error) {
 	r := run(ctx, env, "git", "-C", dir, "ls-files", "--", "module.json", "*/module.json")
 	if r.Status != 0 || r.Err != "" {
-		return nil, fmt.Errorf("git ls-files: %s", firstLine(r.Err+" "+r.Stderr))
+		return nil, fmt.Errorf("git ls-files: %s", forgekey.Said(r.Err+"\n"+r.Stderr))
 	}
 	trees := map[string]ModuleTree{}
 	for _, l := range strings.Split(r.Stdout, "\n") {
@@ -50,7 +50,7 @@ func ModuleTrees(ctx context.Context, run forgekey.Runner, env []string, dir, co
 		}
 		t := run(ctx, env, "git", "-C", dir, "rev-parse", spec)
 		if t.Status != 0 || t.Err != "" {
-			return nil, fmt.Errorf("git rev-parse %s: %s", spec, firstLine(t.Err+" "+t.Stderr))
+			return nil, fmt.Errorf("git rev-parse %s: %s", spec, forgekey.Said(t.Err+"\n"+t.Stderr))
 		}
 		mt := ModuleTree{Tree: strings.TrimSpace(t.Stdout)}
 		raw, err := os.ReadFile(filepath.Join(dir, filepath.FromSlash(l)))
@@ -93,7 +93,7 @@ func narrow(ctx context.Context, run forgekey.Runner, env []string, dir, commit,
 	}
 	r := run(ctx, env, "git", append([]string{"-C", dir, "ls-tree", "-z", commit, "--"}, full...)...)
 	if r.Status != 0 || r.Err != "" {
-		return fmt.Errorf("git ls-tree %s of the module %s: %s", commit, mdir, firstLine(r.Err+" "+r.Stderr))
+		return fmt.Errorf("git ls-tree %s of the module %s: %s", commit, mdir, forgekey.Said(r.Err+"\n"+r.Stderr))
 	}
 	objects := map[string]string{}
 	for _, l := range strings.Split(r.Stdout, "\x00") {

go/buscompose/announced.go

@@ -45,10 +45,25 @@ func ControllerAnnouncement(node string) announce.States {
 // announced the state readable, or announced nothing yet (the transition); refused when the owner announced and did
 // not announce that state readable.
 func ReadsAnnounced(reads []string, announced map[string]announce.States) (granted, refused []string) {
+	return ReadsAnnouncedBy("", reads, announced)
+}
+
+// ReadsAnnouncedBy is ReadsAnnounced for one reader module, which also honours the readers an owner named for a state
+// (announce.State.Readers) and the composer's named readers (NamedReaders, ADR 0547 clause 9): a read named for other
+// modules is refused. An empty reader is judged by the readable mark alone.
+func ReadsAnnouncedBy(reader string, reads []string, announced map[string]announce.States) (granted, refused []string) {
 	for _, r := range reads {
 		owner, name, ok := strings.Cut(r, ".")
 		s, said := announced[owner]
 		switch {
+		case reader != "" && !ReaderMay(reader, r):
+			refused = append(refused, r)
+		case reader != "" && ok && said && s.Keeps(name):
+			if s.ReadableBy(name, reader) {
+				granted = append(granted, r)
+			} else {
+				refused = append(refused, r)
+			}
 		case !ok || !said || s.Readable(name):
 			granted = append(granted, r)
 		default:

go/buscompose/buscompose_test.go

@@ -5,15 +5,19 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"strings"
 	"testing"
 )
 
 // Defends issue 1377 and novox/hq ADR 0547 §5: this is the controller's bus composer copied, and it composes byte for
 // byte what the controller's composes. testdata/controller-user-lists.json was written by the controller's own
-// internal/broker (mesh-controller branch fix/1945-mesh-grants-publishes-memberships), lists and memberships, from fixtures_test.go compiled there unchanged; composed.conf is the
+// internal/broker (mesh-controller branch fix/1945-mesh-grants-publishes-memberships, and fix/1790-grants-create-buckets for the grants part creating declared streams), lists and memberships, from fixtures_test.go compiled there unchanged; composed.conf is the
 // controller's golden of the whole server configuration. A row that differs is the copy drifting from the controller,
 // which is a fault while both compose (until the controller loses its lease, ADR 0547 §13).
+// createdAdvisory is one subscription to a bucket's creation in a composed list, as stateCreatedHeard composes it.
+var createdAdvisory = regexp.MustCompile(`"\$JS\.EVENT\.ADVISORY\.STREAM\.CREATED\.KV_[^"]*", `)
+
 func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 	raw, err := os.ReadFile(filepath.Join("testdata", "controller-user-lists.json"))
 	if err != nil {
@@ -48,6 +52,11 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 			if strings.Join(missing, ",") != strings.Join(want[i].Missing, ",") {
 				t.Errorf("left out %v, the controller %v", missing, want[i].Missing)
 			}
+			// The one row the copy composes beyond the controller's, on purpose (novox/hq issue 1790, 2026-10-26, after
+			// the take-over of ADR 0547 milestone 2): each principal hears its own and read buckets created, so a state
+			// missing at its start is bound when it appears. The controller's composer is frozen and its list no longer
+			// loaded; while it is not, this row is left out of the comparison and nothing else.
+			list = createdAdvisory.ReplaceAllString(list, "")
 			if list != want[i].List {
 				t.Errorf("the list differs from the controller's:\n%s", list)
 			}
@@ -69,6 +78,37 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 			}
 		})
 	}
+	// An asker on a seat pulled by kind hears what that seat's workers gave up on, and no other stream's dead letters
+	// (novox/hq issue 734: a check ask given up during a bus reload left its try running for ever).
+	t.Run("an asker reads its seat's dead letters", func(t *testing.T) {
+		build := Seat{Name: "node-build-go", Scope: "node", Accepts: []string{"delivery", "check", "recheck"}, PulledByKind: true}
+		perms, err := PermissionsFor(Principal{Kind: KindModule, Node: "one", Module: "mesh-delivery-checker", Uses: []Seat{build}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for subject, want := range map[string]bool{
+			"$JS.API.CONSUMER.CREATE.DEAD_LETTERS.x1.mesh.events.dead.SEAT_NODE_BUILD_GO.>":      true,
+			"$JS.API.CONSUMER.CREATE.DEAD_LETTERS.x1.mesh.events.dead.SEAT_NODE_BUILD_GO.w.next": true,
+			"$JS.API.CONSUMER.DELETE.DEAD_LETTERS.x1":                                            true,
+			"$JS.API.CONSUMER.MSG.NEXT.DEAD_LETTERS.x1":                                          true,
+			"$JS.API.CONSUMER.CREATE.DEAD_LETTERS.x1.mesh.events.dead.EVENTS.>":                  false,
+			"$JS.API.CONSUMER.CREATE.DEAD_LETTERS.x1":                                            false,
+			"$JS.API.STREAM.PURGE.DEAD_LETTERS":                                                  false,
+			"$JS.FC.DEAD_LETTERS.x1":                                                             false,
+		} {
+			if got := MayPublish(perms, subject); got != want {
+				t.Errorf("may publish %s: %v, want %v", subject, got, want)
+			}
+		}
+		plain, err := PermissionsFor(Principal{Kind: KindModule, Node: "one", Module: "shop",
+			Uses: []Seat{{Name: "telegram-sender", Accepts: []string{"send"}}}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if MayPublish(plain, "$JS.API.CONSUMER.DELETE.DEAD_LETTERS.x1") {
+			t.Error("a user of a seat not pulled by kind reads DEAD_LETTERS")
+		}
+	})
 	t.Run("the controller's golden server configuration", func(t *testing.T) {
 		seat := Seat{Name: "telegram-sender", Accepts: []string{"send"}, Emits: []string{"delivered", "failed"}}
 		got, err := Compose(

go/buscompose/create.go

@@ -0,0 +1,88 @@
+package buscompose
+
+import (
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// The streams a manifest declares, as the server is asked to create them (novox/hq ADR 0547 §5, issue 1790): the
+// grants part creates each one the bus does not hold yet, with what the controller asserts at its start, so the two
+// make the same stream. Pure. Only a create is ever asked with these: a stream the bus holds is never updated by the
+// grants part (CreateStreamGrants grants no update).
+
+// BucketStreamConfig is a module's bucket as the stream the controller's CreateOrUpdateKeyValue makes of its options
+// (mesh-controller internal/broker BucketConfig, with no marker age held): the client library's key-value shape
+// (rollup, no delete, direct reads, discard new, a duplicate window of two minutes or the age when shorter) with the
+// mesh's caps, file storage and one replica.
+func BucketStreamConfig(b Bucket) jetstream.StreamConfig {
+	history := b.History
+	if history < 1 {
+		history = 1
+	}
+	age := time.Duration(b.TTLSeconds) * time.Second
+	dupes := 2 * time.Minute
+	if age > 0 && age < dupes {
+		dupes = age
+	}
+	cfg := jetstream.StreamConfig{
+		Name:              "KV_" + b.Bucket(),
+		Description:       b.Why(),
+		Subjects:          []string{"$KV." + b.Bucket() + ".>"},
+		MaxMsgsPerSubject: int64(history),
+		MaxBytes:          StateMaxBytes,
+		MaxAge:            age,
+		MaxMsgSize:        StateMaxValueBytes,
+		Storage:           jetstream.FileStorage,
+		Replicas:          1,
+		AllowRollup:       true,
+		DenyDelete:        true,
+		Duplicates:        dupes,
+		MaxMsgs:           -1,
+		MaxConsumers:      -1,
+		AllowDirect:       true,
+		Discard:           jetstream.DiscardNew,
+	}
+	if b.KeyTTL {
+		cfg.AllowMsgTTL, cfg.SubjectDeleteMarkerTTL = true, KeyTTLMarkerTTL
+	}
+	return cfg
+}
+
+// ModuleStreamConfig is a module's own stream as the controller asserts it (mesh-controller internal/broker
+// StreamConfigFor of ModuleStream.Stream).
+func ModuleStreamConfig(m ModuleStream) jetstream.StreamConfig {
+	s := m.Stream()
+	cfg := jetstream.StreamConfig{
+		Name:              s.Name,
+		Subjects:          s.Subjects,
+		Retention:         jetstream.LimitsPolicy,
+		MaxAge:            time.Duration(s.MaxAge) * time.Second,
+		MaxMsgsPerSubject: int64(s.MaxMsgsPerSubject),
+		Description:       s.Why,
+		AllowDirect:       s.Direct,
+		AllowMsgTTL:       s.AllowMsgTTL,
+	}
+	if s.Retention == RetentionWorkQueue {
+		cfg.Retention = jetstream.WorkQueuePolicy
+	}
+	if s.Restricted || s.WorkQueue {
+		cfg.Metadata = map[string]string{}
+		if s.Restricted {
+			cfg.Metadata[RestrictedMetadata] = "true"
+		}
+		if s.WorkQueue {
+			cfg.Metadata[WorkQueueMetadata] = "true"
+		}
+	}
+	if s.MaxBytes > 0 {
+		cfg.MaxBytes = s.MaxBytes
+	}
+	if s.DiscardNew {
+		cfg.Discard = jetstream.DiscardNew
+	}
+	if s.DuplicatesSeconds > 0 {
+		cfg.Duplicates = time.Duration(s.DuplicatesSeconds) * time.Second
+	}
+	return cfg
+}

go/buscompose/create_test.go

@@ -0,0 +1,46 @@
+package buscompose
+
+import (
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// Defends issue 1790 (ADR 0547 §5): the grants part creates a declared bucket and stream as the controller asserts them.
+func TestDeclaredStreamsAreCreatedAsTheControllerAssertsThem(t *testing.T) {
+	plain := BucketStreamConfig(Bucket{Module: "mesh-vault", Name: "bus-accounts"})
+	keyed := BucketStreamConfig(Bucket{Module: "m", Name: "presence", History: 5, TTLSeconds: 60, KeyTTL: true})
+	queue := ModuleStreamConfig(ModuleStream{Module: "b", Name: "ASKS", Events: []string{"ask"}, MaxAgeDays: 7, MaxMiB: 32,
+		WorkQueue: true, Duplicates: 1})
+	for _, row := range []struct {
+		what      string
+		got, want any
+	}{
+		{"bucket name", plain.Name, "KV_mesh-vault_bus-accounts"},
+		{"bucket subjects", plain.Subjects[0], "$KV.mesh-vault_bus-accounts.>"},
+		{"bucket history defaults to one", plain.MaxMsgsPerSubject, int64(1)},
+		{"bucket cap", plain.MaxBytes, int64(StateMaxBytes)},
+		{"bucket value cap", plain.MaxMsgSize, int32(StateMaxValueBytes)},
+		{"bucket duplicate window", plain.Duplicates, 2 * time.Minute},
+		{"bucket discards new", plain.Discard, jetstream.DiscardNew},
+		{"bucket direct and rollup, no delete", plain.AllowDirect && plain.AllowRollup && plain.DenyDelete, true},
+		{"bucket without key ttl", plain.AllowMsgTTL, false},
+		{"history", keyed.MaxMsgsPerSubject, int64(5)},
+		{"age", keyed.MaxAge, time.Minute},
+		{"duplicate window under the age", keyed.Duplicates, time.Minute},
+		{"key ttl markers", keyed.SubjectDeleteMarkerTTL, KeyTTLMarkerTTL},
+		{"key ttl", keyed.AllowMsgTTL, true},
+		{"queue retention", queue.Retention, jetstream.WorkQueuePolicy},
+		{"queue subjects", queue.Subjects[0], "mesh.stream.b.event.ask"},
+		{"queue age", queue.MaxAge, 7 * 24 * time.Hour},
+		{"queue cap", queue.MaxBytes, int64(32 << 20)},
+		{"queue discards new", queue.Discard, jetstream.DiscardNew},
+		{"queue duplicates", queue.Duplicates, time.Hour},
+		{"queue metadata", queue.Metadata[WorkQueueMetadata] + queue.Metadata[RestrictedMetadata], "truetrue"},
+	} {
+		if row.got != row.want {
+			t.Errorf("%s: %v, want %v", row.what, row.got, row.want)
+		}
+	}
+}

go/buscompose/creates_streams_test.go

@@ -0,0 +1,130 @@
+package buscompose
+
+import "testing"
+
+// Defends issue 1790 and novox/hq ADR 0547 §5 (the operator, 2026-10-26 08:54): the grants part may create the stream
+// of each bucket, log and stream a placed module's manifest declares, by its own name, and read it back; nothing
+// wider, nothing updated or deleted, and no other principal so. Held byte-equal in the controller's copy. And ADR 0547
+// clause 7 (issue 1945, the operator's second exception): the grants part writes its own object bucket of sealed user
+// lists, and the node-engine of the node holding mesh-broker alone reads its one key and an object of it by name.
+func TestTheGrantsPartCreatesOnlyDeclaredStreams(t *testing.T) {
+	records := Records{
+		Nodes: []string{"novox", "ace"},
+		Assigned: map[string][]Declared{"ace": {{Module: "plex"}}, "novox": {
+			{Module: "nats", SnapshotsTheBus: true},
+			// mesh-sdk's copy alone (ADR 0547 clause 9, named readers): the vault's hashes are read by the grants part
+			// alone, whatever another module's reads say; the controller's copy grants any module that declares it.
+			{Module: "mesh-vault", State: []Bucket{{Module: "mesh-vault", Name: "bus-accounts"}}},
+			{Module: "spy", Serves: []string{"spy_x"}, Reads: []string{VaultBusAccounts}},
+			{Module: "mesh-delivery-builder",
+				State:   []Bucket{{Module: "mesh-delivery-builder", Name: "steps", History: 5}},
+				Logs:    []Log{{Module: "mesh-delivery-builder", Name: "builds"}},
+				Streams: []ModuleStream{{Module: "mesh-delivery-builder", Name: "BUILDASKS", Events: []string{"ask"}}}},
+			{Module: GrantsModule, State: []Bucket{{Module: GrantsModule, Name: "assertions"}}, Reads: []string{VaultBusAccounts}},
+			{Module: RuntimeModule},
+		}},
+	}
+	users, err := Users(records)
+	if err != nil {
+		t.Fatal(err)
+	}
+	perms := map[string]Permissions{}
+	for _, u := range users {
+		if u.Kind == KindNode || u.Kind == KindNodeTools {
+			p, err := PermissionsFor(u)
+			if err != nil {
+				t.Fatalf("%s: %v", u.Username(), err)
+			}
+			perms[u.Username()] = p
+			continue
+		}
+		if u.Kind != KindModule {
+			continue
+		}
+		p, err := PermissionsFor(u)
+		if err != nil {
+			t.Fatalf("%s: %v", u.Username(), err)
+		}
+		perms[u.Module] = p
+	}
+	for _, row := range []struct {
+		who, subject string
+		may          bool
+	}{
+		{GrantsModule, "$JS.API.STREAM.CREATE.KV_mesh-delivery-builder_steps", true},
+		{GrantsModule, "$JS.API.STREAM.INFO.KV_mesh-delivery-builder_steps", true},
+		{GrantsModule, "$JS.API.STREAM.CREATE.LOG_mesh-delivery-builder_builds", true},
+		{GrantsModule, "$JS.API.STREAM.CREATE.BUILDASKS", true},
+		{GrantsModule, "$JS.API.STREAM.CREATE.KV_mesh-grants_assertions", true},
+		{GrantsModule, "$JS.API.STREAM.UPDATE.KV_mesh-delivery-builder_steps", false},
+		{GrantsModule, "$JS.API.STREAM.DELETE.KV_mesh-delivery-builder_steps", false},
+		{GrantsModule, "$JS.API.STREAM.PURGE.KV_mesh-delivery-builder_steps", false},
+		{GrantsModule, "$JS.API.STREAM.CREATE.KV_mesh-delivery-builder_undeclared", false},
+		{GrantsModule, "$JS.API.STREAM.CREATE.EVENTS", false},
+		{GrantsModule, "$JS.API.STREAM.CREATE.ASSIGNMENTS", false},
+		{GrantsModule, "$JS.API.STREAM.INFO.EVENTS", false},
+		{"mesh-delivery-builder", "$JS.API.STREAM.CREATE.KV_mesh-delivery-builder_steps", false},
+		// The sealed user list (ADR 0547 clause 7): the grants part writes its own bucket and no other.
+		{GrantsModule, "$JS.API.STREAM.CREATE.OBJ_mesh-grants-user-list", true},
+		{GrantsModule, "$O.mesh-grants-user-list.C.abc", true},
+		{GrantsModule, "$JS.API.STREAM.PURGE.OBJ_mesh-grants-user-list", true},
+		{GrantsModule, "$O.declaration-files-novox.C.abc", false},
+		{GrantsModule, "$JS.API.STREAM.DELETE.OBJ_mesh-grants-user-list", false},
+		{"mesh-delivery-builder", "$O.mesh-grants-user-list.C.abc", false},
+		// The bus node's engine reads the one key and an object by name; nothing of the bucket's list, no write.
+		{"node.novox", "$JS.API.DIRECT.GET.KV_mesh-grants_user-list.$KV.mesh-grants_user-list.sealed", true},
+		{"node.novox", "$JS.API.CONSUMER.CREATE.KV_mesh-grants_user-list.abc.$KV.mesh-grants_user-list.sealed", true},
+		{"node.novox", "$JS.API.DIRECT.GET.OBJ_mesh-grants-user-list.$O.mesh-grants-user-list.M.abc", true},
+		{"node.novox", "$JS.API.CONSUMER.CREATE.OBJ_mesh-grants-user-list.abc.$O.mesh-grants-user-list.C.abc", true},
+		{"node.novox", "$JS.API.DIRECT.GET.KV_mesh-grants_user-list.$KV.mesh-grants_user-list.list", false},
+		{"node.novox", "$JS.API.STREAM.INFO.OBJ_mesh-grants-user-list", false},
+		{"node.novox", "$JS.API.STREAM.MSG.GET.OBJ_mesh-grants-user-list", false},
+		{"node.novox", "$O.mesh-grants-user-list.C.abc", false},
+		{"node.ace", "$JS.API.DIRECT.GET.KV_mesh-grants_user-list.$KV.mesh-grants_user-list.sealed", false},
+		{"node.ace", "$JS.API.DIRECT.GET.OBJ_mesh-grants-user-list.$O.mesh-grants-user-list.M.abc", false},
+		{GrantsModule, "$JS.API.DIRECT.GET.KV_mesh-vault_bus-accounts.$KV.mesh-vault_bus-accounts.x", true},
+		{"spy", "$JS.API.DIRECT.GET.KV_mesh-vault_bus-accounts.$KV.mesh-vault_bus-accounts.x", false},
+		{"novox.node-tools", "$JS.API.DIRECT.GET.KV_mesh-vault_bus-accounts.$KV.mesh-vault_bus-accounts.x", false},
+	} {
+		if got := MayPublish(perms[row.who], row.subject); got != row.may {
+			t.Errorf("%s may publish %s: %v, want %v", row.who, row.subject, got, row.may)
+		}
+	}
+	// Issue 1790 (2026-10-26): a module hears the bus create each bucket it may bind, its own and those it reads, so a
+	// state missing at its start is bound when it appears; no other bucket's, and no other advisory.
+	for _, row := range []struct {
+		who, subject string
+		may          bool
+	}{
+		{"mesh-delivery-builder", "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-delivery-builder_steps", true},
+		{GrantsModule, "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-vault_bus-accounts", true},
+		{"mesh-delivery-builder", "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-grants_assertions", false},
+		{"mesh-delivery-builder", "$JS.EVENT.ADVISORY.STREAM.CREATED.LOG_mesh-delivery-builder_builds", false},
+		{"mesh-delivery-builder", "$JS.EVENT.ADVISORY.STREAM.DELETED.KV_mesh-delivery-builder_steps", false},
+	} {
+		if got := MaySubscribe(perms[row.who], row.subject); got != row.may {
+			t.Errorf("%s may hear %s: %v, want %v", row.who, row.subject, got, row.may)
+		}
+	}
+	// A name that is no plain token is never granted, and a module other than the grants part is never granted one.
+	if got := CreateStreamGrants([]string{"*", ">", "KV_a.b", "KV_a_b"}); len(got) != 2 {
+		t.Errorf("grants for wildcard names: %v", got)
+	}
+	other, err := PermissionsFor(Principal{Kind: KindModule, Node: "novox", Module: "shop", CreatesStreams: []string{"KV_shop_x"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if MayPublish(other, "$JS.API.STREAM.CREATE.KV_shop_x") {
+		t.Error("a module other than the grants part was granted a create")
+	}
+	// The writers table refuses the grants part an update, and a create of a stream it was not given.
+	g := Principal{Kind: KindModule, Node: "novox", Module: GrantsModule, CreatesStreams: []string{"KV_a_b"}}
+	if err := CheckWriters(g, []string{"$JS.API.STREAM.CREATE.KV_a_b"}); err != nil {
+		t.Errorf("the declared create refused: %v", err)
+	}
+	for _, refused := range []string{"$JS.API.STREAM.UPDATE.KV_a_b", "$JS.API.STREAM.CREATE.KV_a_c", "$JS.API.STREAM.CREATE.*"} {
+		if CheckWriters(g, []string{refused}) == nil {
+			t.Errorf("%s was not refused", refused)
+		}
+	}
+}

go/buscompose/doc.go

@@ -3,7 +3,7 @@
 // streams, state and logs it composes them from.
 //
 // **A copy of the controller's internal/broker, composer half** (issue 1377, novox/hq ADR 0547 §5), taken at
-// mesh-controller 7cd4d18b with the grants part's membership grant of f67d1553 (ADR 0547 §5): the bus client (jetstream.go), the broker's address from the environment (broker.go, onnats.go
+// mesh-controller 7cd4d18b with the grants part's membership grant of f67d1553 (ADR 0547 §5) and its grant to create the streams manifests declare (issue 1790): the bus client (jetstream.go), the broker's address from the environment (broker.go, onnats.go
 // but its one constant) and the two methods on that client are left out; the lease's two subjects are copied in
 // (nats.go). The controller keeps its own copy, unchanged, until it loses its lease at ADR 0547's third milestone, so
 // for that time two composers state who may say what and must say the same: TestTheCopiedComposerComposesAsTheControllers

go/buscompose/fixtures_test.go

@@ -62,6 +62,9 @@ func UserListFixtures() []UserListFixture {
 					},
 					{Module: "mesh-delivery-view", Reads: []string{"mesh-delivery-builder.steps"},
 						KeyedReads: []KeyedRead{{Read: "mesh-delivery-builder.presence", Key: "novox"}}},
+					// The grants part, which may create every stream declared here (ADR 0547 §5, issue 1790).
+					{Module: "mesh-grants", Emits: []string{"membership-changed"},
+						State: []Bucket{{Module: "mesh-grants", Name: "assertions", History: 5}}},
 				},
 				"ace": {
 					{Module: "plex", Serves: []string{"plex_status"}, Checks: []string{"plex.plex_status"}},

go/buscompose/nats.go

@@ -213,9 +213,17 @@ type Principal struct {
 	// StatesItsKeyToTheVault is a machine principal whose node-engine may ask the vault's `node-key` in its own name
 	// (issue 786, novox/hq ADR 0372): set while the vault's holder serves it. That one verb, and nothing else new.
 	StatesItsKeyToTheVault bool
+	// FollowsGrantsUserList is the machine principal of the node holding mesh-broker: its node-engine reads the grants
+	// part's sealed user list, one key and an object by name (novox/hq ADR 0547 clause 7, GrantsUserListFollows).
+	FollowsGrantsUserList bool
 	// BoundBuckets are the providers' buckets of entries, `<module>_bound`, a provisioner client reads its own
 	// machine's keys of (mesh-sdk go/provider, issue 679): every bucket named bound of a module the mesh places.
 	BoundBuckets []string
+	// CreatesStreams are the streams the grants part's principal alone may create (novox/hq ADR 0547 §5; the operator,
+	// 2026-10-26 08:54): the stream of every bucket, log and stream a manifest of a module placed anywhere declares,
+	// by name. Created only, never updated or deleted: a new module state is on the bus when the grants part hears its
+	// manifest, not at the controller's next start (issue 1790).
+	CreatesStreams []string
 
 	// PasswordHash is the bcrypt hash the mesh minted. The plaintext is sealed to the principal
 	// and never appears here: this file is written to a node's disk and read by a server, and a
@@ -907,6 +915,11 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		if p.StatesItsKeyToTheVault {
 			pub = append(pub, "mesh.seat."+VaultNodeKey.Seat+"."+CallKind+"."+VaultNodeKey.Verb+"."+CallerToken(p.Username()))
 		}
+		// And, on the node holding mesh-broker, the grants part's sealed user list it follows from take-over (novox/hq ADR
+		// 0547 clause 7): one key, and an object by its name.
+		if p.FollowsGrantsUserList {
+			pub = append(pub, GrantsUserListFollows()...)
+		}
 
 	case KindModule:
 		// 0. The watchman alone hears who connects and disconnects, and asks who is connected (ADR 0431 §2).
@@ -919,6 +932,11 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		// first so it publishes only what changed, and no stream it defines.
 		if p.Module == GrantsModule {
 			pub = append(pub, "mesh.assignment.*.*", "$JS.API.DIRECT.GET."+AssignmentsStream+".mesh.assignment.*.*")
+			// And creating each stream a manifest declares, by its own name (the operator, 2026-10-26 08:54; issue
+			// 1790): the create and the read of that one stream, never an update, a delete or a stream not declared.
+			pub = append(pub, CreateStreamGrants(p.CreatesStreams)...)
+			// And its own object bucket, where it writes the user list sealed to the bus node (ADR 0547 clause 7).
+			pub = append(pub, GrantsUserListWrites()...)
 		}
 		// The view alone reads the build seats' workers for the backlog of asks (issue 1887 A8a).
 		if p.Module == ViewModule {
@@ -1067,8 +1085,12 @@ func PermissionsFor(p Principal) (Permissions, error) {
 
 		// 5. Its state, and the state of others it reads (novox/hq ADR 0201): every one read and
 		//    watched, its own written too.
-		pub = append(pub, stateGrants(stateAccess{Module: p.Module, Node: p.Node, Keeps: p.State,
-			PerMachine: p.PerMachine, Reads: p.Reads, KeyedReads: p.KeyedReads})...)
+		kept := stateAccess{Module: p.Module, Node: p.Node, Keeps: p.State, PerMachine: p.PerMachine, Reads: p.Reads,
+			KeyedReads: p.KeyedReads}
+		pub = append(pub, stateGrants(kept)...)
+		// And it hears each of those buckets created, so one not on the bus at its start is bound when it appears
+		// (novox/hq issue 1790; mesh-sdk process.AwaitBucket).
+		sub = append(sub, stateCreatedHeard(kept)...)
 		// And its logs (novox/hq ADR 0297): appended to and read directly, its own alone.
 		pub = append(pub, logGrants(p.Module, p.Logs)...)
 
@@ -1586,6 +1608,20 @@ func ComposeAccounts(principals []Principal) (string, error) {
 // from them. No other principal is granted the subjects below, and nothing is a wildcard over them.
 const WatchmanModule = "mesh-delivery-watchman"
 
+// CreateStreamGrants is what creating each named stream needs, and nothing wider (novox/hq ADR 0547 §5; the operator,
+// 2026-10-26 08:54): its create, and its information to read back what it holds. Each by its own name: a name that
+// is not one plain subject token is left out, since a wildcard there would be every stream.
+func CreateStreamGrants(streams []string) []string {
+	var out []string
+	for _, s := range streams {
+		if !safeSubject.MatchString(s) {
+			continue
+		}
+		out = append(out, "$JS.API.STREAM.CREATE."+s, "$JS.API.STREAM.INFO."+s)
+	}
+	return out
+}
+
 // GrantsModule is the one module whose principal publishes the modules' memberships (novox/hq ADR 0547 §5): the grants
 // part, which composes them from the manifests and placement. It defines no stream and is granted no other subject here.
 const GrantsModule = "mesh-grants"

go/buscompose/process_grants.go

@@ -30,7 +30,11 @@ func processGrants(p Principal) (pub, sub []string, err error) {
 
 	// 3. Its module's own state, by the local names its bus names alone — never the whole of what the
 	// module keeps (novox/hq ADR 0436 §1), read and written as stateGrants gives any module's own bucket.
-	pub = append(pub, stateGrants(stateAccess{Module: p.Module, Node: p.Node, Keeps: p.State})...)
+	kept := stateAccess{Module: p.Module, Node: p.Node, Keeps: p.State}
+	pub = append(pub, stateGrants(kept)...)
+	// And it hears each of them created, so one not on the bus at its start is bound when it appears (novox/hq issue
+	// 1790; process.AwaitBucket).
+	sub = append(sub, stateCreatedHeard(kept)...)
 
 	// 4. The router's records of its module's own asks (novox/hq ADR 0436 §1, ADR 0259 §3): the same
 	// direct-get subjects a module's own principal reads for the seats its Uses names that keep them —

go/buscompose/seattraffic.go

@@ -24,8 +24,9 @@ import (
 //     subjects cover it, so what travels there — a code typed by the operator — is never persisted. A kinded
 //     holder asks with its own kind; the modules that watch the seat answer.
 //
-// And one read: **a holder's records**, a bucket the seat names, read by each user under its own name only
-// (`$KV.<bucket>.<module>.>`), so an asker reads the state of its own asks and no other asker's.
+// And two reads: **a holder's records**, a bucket the seat names, read by each user under its own name only
+// (`$KV.<bucket>.<module>.>`), so an asker reads the state of its own asks and no other asker's; and on a seat pulled by
+// kind, **what its workers gave up on**, the copies DEAD_LETTERS keeps of the seat's stream (DeadLetterReads, issue 734).
 
 // BuildAskMaxDeliver bounds the deliveries of a build seat's ask (issue 1907): mesh-sdk delivery.AskMaxDeliver, written
 // here as the broker mirrors the catalogue rather than importing it.
@@ -129,6 +130,9 @@ func SeatTrafficOf(module string, holds, uses, watches []Seat) SeatTraffic {
 			}
 			t.Records = append(t.Records, "$JS.API.DIRECT.GET.KV_"+b+".$KV."+b+"."+module+".>")
 		}
+		if s.PulledByKind && len(s.Accepts) > 0 && safeSubject.MatchString(s.Name) {
+			t.Records = append(t.Records, DeadLetterReads(seatStreamName(s.Name))...)
+		}
 	}
 	for _, w := range watches {
 		if w.Kinded {
@@ -151,6 +155,20 @@ func SeatTrafficOf(module string, holds, uses, watches []Seat) SeatTraffic {
 	return t
 }
 
+// DeadLetterReads is what a user of a seat pulled by kind is granted to hear which of the asks it put the seat's workers
+// gave up on (novox/hq issue 734): an ordered consumer on DEAD_LETTERS filtered to the copies the controller keeps of that
+// seat's stream (DeadLetterSubject(stream, *)), pulled, and its deletion. A copy carries the ask's own message id
+// (Mesh-Dead-Msg-Id), so the asker ends the step it waits for instead of waiting for ever; it reads the seat's dead
+// letters and no other stream's, and changes none.
+func DeadLetterReads(stream string) []string {
+	return []string{
+		"$JS.API.STREAM.INFO." + DeadLettersStream,
+		"$JS.API.CONSUMER.CREATE." + DeadLettersStream + ".*." + DeadLetterSubject(stream, ">"),
+		"$JS.API.CONSUMER.MSG.NEXT." + DeadLettersStream + ".*",
+		"$JS.API.CONSUMER.DELETE." + DeadLettersStream + ".*",
+	}
+}
+
 // seatTrafficGrants is the bus permissions seat traffic needs: the subjects themselves, and the JetStream API a
 // worker is pulled and acknowledged through and a record is read through.
 func seatTrafficGrants(t SeatTraffic) (pub, sub []string) {

go/buscompose/state.go

@@ -166,6 +166,49 @@ func stateGrants(a stateAccess) []string {
 	return out
 }
 
+// StreamCreatedAdvisory is the subject the bus says a stream was created on (the server's own advisory), here for a
+// bucket's stream KV_<bucket>.
+func StreamCreatedAdvisory(bucket string) string {
+	return "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_" + bucket
+}
+
+// stateCreatedHeard is what a principal subscribes to so that a bucket it may bind and that is not on the bus yet is
+// bound when it appears (novox/hq issue 1790, 2026-10-26: since the grants part creates a manifest's buckets, ADR 0547,
+// a module's delivery can start it before its new state exists): the bus's advisory that the bucket's stream was
+// created, for each bucket stateGrants lets it bind, and no other. Read-only: the server publishes it in the mesh's own
+// account, and hearing it changes nothing.
+func stateCreatedHeard(a stateAccess) []string {
+	var out []string
+	seen := map[string]bool{}
+	add := func(bucket string) {
+		if !seen[bucket] {
+			seen[bucket] = true
+			out = append(out, StreamCreatedAdvisory(bucket))
+		}
+	}
+	perMachine := map[string]bool{}
+	for _, n := range a.PerMachine {
+		perMachine[n] = true
+	}
+	for _, name := range a.Keeps {
+		if !safeSubject.MatchString(name) || (perMachine[name] && !safeSubject.MatchString(a.Node)) {
+			continue
+		}
+		add(BucketName(a.Module, name))
+	}
+	for _, r := range a.Reads {
+		if bucket, ok := bucketOfRead(r); ok {
+			add(bucket)
+		}
+	}
+	for _, k := range a.KeyedReads {
+		if bucket, ok := bucketOfRead(k.Read); ok && safeSubject.MatchString(k.Key) {
+			add(bucket)
+		}
+	}
+	return out
+}
+
 // KeyedRead is one key of another module's state a principal reads, and no other key of it.
 type KeyedRead struct {
 	Read string `json:"read"`

go/buscompose/userlist_switch.go

@@ -0,0 +1,111 @@
+package buscompose
+
+import (
+	"slices"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **The grants part's user list, sealed to the bus node** (novox/hq ADR 0547 clause 7, issue 1945). The grants part writes
+// the list it composed as one object of its own object bucket, sealed to the key of the node holding mesh-broker, and
+// names it in one key of its own state `user-list`. The node-engine of that node follows the key when the switch says
+// so (clause 8), opens the object and writes the bus's user-list file.
+//
+// Who may do what, and nothing more:
+//
+//   - the grants part writes its object bucket (create, put, purge of an object's old chunks, delete) and its own state
+//     as before;
+//   - the node-engine of the node holding mesh-broker reads that one key of the state, watched, and an object of the
+//     bucket by its name: never the bucket's list of names, never a write, never another key of the grants part's state;
+//   - no other principal touches either.
+
+// GrantsUserListBucket, GrantsUserListKey, GrantsUserListObjects and GrantsUserListObjectStream are delivery's names,
+// here where the grants are composed.
+const (
+	GrantsUserListBucket       = delivery.GrantsUserListBucket
+	GrantsUserListKey          = delivery.GrantsUserListKey
+	GrantsUserListObjects      = delivery.GrantsUserListObjects
+	GrantsUserListObjectStream = delivery.GrantsUserListObjectStream
+)
+
+// GrantsUserListFollows is what the node-engine of the node holding mesh-broker may publish to follow the grants part's
+// list: the one key `user-list.sealed` read and watched (its own ordered consumer, filtered on that key alone), and an
+// object of the bucket by its name, as a node reads its declaration's files (ADR 0486 §2: never STREAM.INFO of the object
+// stream, which lists every name, and never STREAM.MSG.GET).
+func GrantsUserListFollows() []string {
+	kv := "KV_" + GrantsUserListBucket
+	key := "$KV." + GrantsUserListBucket + "." + GrantsUserListKey
+	obj, s := GrantsUserListObjects, GrantsUserListObjectStream
+	return []string{
+		"$JS.API.DIRECT.GET." + kv + "." + key,
+		"$JS.API.CONSUMER.CREATE." + kv + ".*." + key,
+		"$JS.API.CONSUMER.DELETE." + kv + ".*",
+		"$JS.API.STREAM.INFO." + kv,
+		"$JS.FC." + kv + ".>",
+		"$JS.API.DIRECT.GET." + s + ".$O." + obj + ".M.*",
+		"$JS.API.CONSUMER.CREATE." + s + ".*.$O." + obj + ".C.*",
+		"$JS.API.CONSUMER.DELETE." + s + ".*",
+		"$JS.FC." + s + ".>",
+	}
+}
+
+// GrantsUserListWrites is what the grants part may publish to keep its object bucket: create it and read its info back,
+// put an object (its chunks and its metadata, the old chunks of a name purged), read an object's metadata, and delete
+// one. Its own state `user-list` it writes already, as every module writes its own.
+func GrantsUserListWrites() []string {
+	obj, s := GrantsUserListObjects, GrantsUserListObjectStream
+	return []string{
+		"$JS.API.STREAM.CREATE." + s,
+		"$JS.API.STREAM.INFO." + s,
+		"$JS.API.STREAM.PURGE." + s,
+		"$JS.API.DIRECT.GET." + s + ".>",
+		"$JS.API.STREAM.MSG.GET." + s,
+		"$O." + obj + ".>",
+	}
+}
+
+// grantsOwnObjects is the grants part writing its own object bucket, and nothing of another.
+func grantsOwnObjects(p Principal, pattern string) bool {
+	return p.Kind == KindModule && p.Module == GrantsModule &&
+		(pattern == "$O."+GrantsUserListObjects+".>" || pattern == "$JS.API.STREAM.CREATE."+GrantsUserListObjectStream)
+}
+
+// **Named readers** (novox/hq ADR 0547 clause 9, progressive insight of 2026-10-26; issue 1945). A state named here is
+// read by the modules named and by no other, whatever another module's `reads` says: the vault's `bus-accounts` holds
+// every bus account's bcrypt hash, and from take-over the grants part alone may read it. A module's announcement may name
+// readers too (announce.State.Readers); both are honoured.
+const VaultBusAccounts = "mesh-vault.bus-accounts"
+
+// NamedReaders are the states only the modules named may read, by `<owner>.<name>`.
+var NamedReaders = map[string][]string{VaultBusAccounts: {GrantsModule}}
+
+// ReaderMay says whether module may read the state read (`<owner>.<name>`) by the named readers: always, for a state
+// that names none.
+func ReaderMay(module, read string) bool {
+	readers, named := NamedReaders[read]
+	return !named || slices.Contains(readers, module)
+}
+
+// readsNamed splits a module's reads by the named readers: those it may read, and those named for others.
+func readsNamed(module string, reads []string) (granted, refused []string) {
+	for _, r := range reads {
+		if ReaderMay(module, strings.TrimSpace(r)) {
+			granted = append(granted, r)
+		} else {
+			refused = append(refused, r)
+		}
+	}
+	return granted, refused
+}
+
+// withNamedReaders is d with the reads named for other modules moved to its refused reads.
+func withNamedReaders(d Declared) Declared {
+	granted, refused := readsNamed(d.Module, d.Reads)
+	if len(refused) == 0 {
+		return d
+	}
+	d.Reads = granted
+	d.ReadsRefused = append(append([]string(nil), d.ReadsRefused...), refused...)
+	return d
+}

go/buscompose/userlist_switch_integration_test.go

@@ -0,0 +1,213 @@
+//go:build integration
+
+package buscompose
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/seal"
+	"github.com/nats-io/nats-server/v2/server"
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// Defends novox/hq ADR 0547 clause 7 on a real server (issue 1945): with the list this composer writes, the grants part
+// creates its object bucket and its state, puts the sealed list and names it in `user-list.sealed`; the node-engine of
+// the node holding mesh-broker watches that one key, reads the object by its name and opens it with its key, and may
+// neither list the bucket, nor read another key of the state, nor write; another node reads nothing of either.
+func TestTheBusNodeFollowsTheGrantsPartsSealedListUnderTheComposedGrants(t *testing.T) {
+	records := Records{
+		Nodes: []string{"novox", "ace"},
+		Assigned: map[string][]Declared{
+			"novox": {{Module: "nats", SnapshotsTheBus: true},
+				{Module: GrantsModule, State: []Bucket{{Module: GrantsModule, Name: "user-list"}}}},
+			"ace": {{Module: "plex"}},
+		},
+	}
+	users, err := Users(records)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i := range users {
+		users[i].PasswordHash = "pw-" + users[i].Username()
+	}
+	accounts, err := ComposeAccounts(users)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dir := t.TempDir()
+	conf := filepath.Join(dir, "server.conf")
+	if err := os.WriteFile(conf, []byte("listen: 127.0.0.1:-1\njetstream { store_dir: \""+dir+"\" }\n"+accounts), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	opts, err := server.ProcessConfigFile(conf)
+	if err != nil {
+		t.Fatalf("the composed list is not the server's: %v", err)
+	}
+	opts.NoLog, opts.NoSigs = true, true
+	s, err := server.NewServer(opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	go s.Start()
+	if !s.ReadyForConnections(30 * time.Second) {
+		t.Fatal("the bus did not come up")
+	}
+	t.Cleanup(s.Shutdown)
+	dial := func(user string) *nats.Conn {
+		nc, err := nats.Connect(s.ClientURL(), nats.UserInfo(user, "pw-"+user), nats.CustomInboxPrefix("_INBOX."+user))
+		if err != nil {
+			t.Fatalf("%s: %v", user, err)
+		}
+		t.Cleanup(nc.Close)
+		return nc
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// The grants part: its state and its object bucket, the sealed list put and named.
+	grants, err := jetstream.New(dial("novox." + GrantsModule))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Its state is made as the grants part makes a declared state, by its stream's name (CreateKeyValue would ask the
+	// account's info, which no module is granted).
+	if _, err := grants.CreateStream(ctx, jetstream.StreamConfig{Name: "KV_" + GrantsUserListBucket,
+		Subjects: []string{"$KV." + GrantsUserListBucket + ".>"}, MaxMsgsPerSubject: 1, AllowDirect: true,
+		AllowRollup: true, DenyDelete: true, Discard: jetstream.DiscardNew}); err != nil {
+		t.Fatalf("the grants part's state: %v", err)
+	}
+	kv, err := grants.KeyValue(ctx, GrantsUserListBucket)
+	if err != nil {
+		t.Fatalf("the grants part binds its state: %v", err)
+	}
+	objects, err := grants.CreateObjectStore(ctx, jetstream.ObjectStoreConfig{Bucket: GrantsUserListObjects})
+	if err != nil {
+		t.Fatalf("the grants part's object bucket: %v", err)
+	}
+	node, err := seal.GenerateKeyPair()
+	if err != nil {
+		t.Fatal(err)
+	}
+	list := []byte(accounts)
+	digest := delivery.UserListDigest(list)
+	object, err := delivery.SealUserList(list, node.PublicKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	name := delivery.UserListObjectName(digest)
+	for range 2 { // put twice: a second put of a name purges its old chunks
+		if _, err := objects.PutBytes(ctx, name, object); err != nil {
+			t.Fatalf("the grants part put its object: %v", err)
+		}
+	}
+	value, err := delivery.EncodeGrantsUserList(delivery.GrantsUserList{Follow: delivery.FollowGrants, Digest: digest,
+		Object: name, SealedTo: delivery.SealingKeyID(node.PublicKey), Node: "novox", Revision: 1, Users: len(users)})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := kv.Put(ctx, GrantsUserListKey, value); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := kv.Put(ctx, "list", []byte(`{"v":1}`)); err != nil {
+		t.Fatal(err)
+	}
+
+	// The bus node's engine: the key watched, the object by name (as mesh-host's link reads a declaration's file).
+	busNode := dial("node.novox")
+	js, err := busNode.JetStream(nats.MaxWait(5 * time.Second))
+	if err != nil {
+		t.Fatal(err)
+	}
+	keys, err := js.KeyValue(GrantsUserListBucket)
+	if err != nil {
+		t.Fatalf("the bus node binds the grants part's state: %v", err)
+	}
+	w, err := keys.Watch(GrantsUserListKey)
+	if err != nil {
+		t.Fatalf("the bus node watches the key: %v", err)
+	}
+	defer w.Stop()
+	var got delivery.GrantsUserList
+	select {
+	case e := <-w.Updates():
+		if e == nil {
+			t.Fatal("the watch found no value")
+		}
+		if got, err = delivery.DecodeGrantsUserList(e.Value()); err != nil {
+			t.Fatal(err)
+		}
+	case <-ctx.Done():
+		t.Fatal("the watch said nothing")
+	}
+	read := func(js nats.JetStreamContext, name string) ([]byte, error) {
+		meta, err := js.GetLastMsg(GrantsUserListObjectStream, "$O."+GrantsUserListObjects+".M."+
+			base64.URLEncoding.EncodeToString([]byte(name)), nats.DirectGet())
+		if err != nil {
+			return nil, err
+		}
+		var info struct {
+			NUID string `json:"nuid"`
+			Size int    `json:"size"`
+		}
+		if err := json.Unmarshal(meta.Data, &info); err != nil {
+			return nil, err
+		}
+		sub, err := js.SubscribeSync("$O."+GrantsUserListObjects+".C."+info.NUID, nats.OrderedConsumer(),
+			nats.BindStream(GrantsUserListObjectStream))
+		if err != nil {
+			return nil, err
+		}
+		defer sub.Unsubscribe()
+		var body []byte
+		for len(body) < info.Size {
+			m, err := sub.NextMsg(5 * time.Second)
+			if err != nil {
+				return nil, err
+			}
+			body = append(body, m.Data...)
+		}
+		return body, nil
+	}
+	body, err := read(js, got.Object)
+	if err != nil {
+		t.Fatalf("the bus node reads the object by its name: %v", err)
+	}
+	opened, err := delivery.OpenUserList(body, got.Digest, func(b seal.Box) ([]byte, error) {
+		s, err := seal.Open(b, node.PrivateKey)
+		return []byte(s), err
+	})
+	if err != nil || !bytes.Equal(opened, list) {
+		t.Fatalf("the bus node opened %d bytes, %v", len(opened), err)
+	}
+
+	// And nothing beyond: no other key, no list of the bucket, no write.
+	if _, err := keys.Get("list"); err == nil {
+		t.Error("the bus node read another key of the grants part's state")
+	}
+	if _, err := js.StreamInfo(GrantsUserListObjectStream); err == nil {
+		t.Error("the bus node read the object stream's info, which lists every name")
+	}
+	if _, err := js.Publish("$O."+GrantsUserListObjects+".M.x", []byte("x")); err == nil {
+		t.Error("the bus node wrote the grants part's bucket")
+	}
+	// Another node reads nothing of it.
+	other, err := dial("node.ace").JetStream(nats.MaxWait(2 * time.Second))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := read(other, got.Object); err == nil {
+		t.Error("another node read the object")
+	}
+	if _, err := other.GetLastMsg("KV_"+GrantsUserListBucket, "$KV."+GrantsUserListBucket+"."+GrantsUserListKey, nats.DirectGet()); err == nil {
+		t.Errorf("another node read the key: %v", err)
+	}
+}

go/buscompose/users.go

@@ -147,14 +147,19 @@ func Users(r Records) ([]Principal, error) {
 	for _, node := range sortedCopy(r.Nodes) {
 		witness := false
 		var checks []string
+		bus := false
 		for _, d := range r.Assigned[node] {
 			if d.Module == controllerModule {
 				witness = true
 			}
+			if d.SnapshotsTheBus {
+				bus = true
+			}
 			checks = append(checks, d.Checks...)
 		}
 		out = append(out, Principal{Kind: KindNode, Node: node, WitnessesController: witness, Checks: checks,
-			MovesIntoTheVault: servesMoveIn(r), StatesItsKeyToTheVault: servesVerb(r, VaultNodeKey)})
+			MovesIntoTheVault: servesMoveIn(r), StatesItsKeyToTheVault: servesVerb(r, VaultNodeKey),
+			FollowsGrantsUserList: bus})
 		// **And the machine's provisioner client, on an account of its own** (novox/hq ADR 0349 clause 11): one
 		// per machine that runs it, delivered to the module running it.
 		for _, d := range r.Assigned[node] {
@@ -176,6 +181,9 @@ func Users(r Records) ([]Principal, error) {
 			}
 		}
 		for _, d := range r.Assigned[node] {
+			// A state with named readers is read by them alone (ADR 0547 clause 9): a read named for another module is
+			// granted nothing, here and in the runtime carrying the module.
+			d = withNamedReaders(d)
 			// **A process account is its own, delivered in its own secret** (broker-<process id>, novox/hq
 			// ADR 0436 §1, §2), never the module's `broker` — so it is composed whether or not the module
 			// itself has an account, and is never carried by the machine's runtime, which runs as the
@@ -207,6 +215,11 @@ func Users(r Records) ([]Principal, error) {
 				PerMachine: perMachineNames(d.State), KeyedReads: d.KeyedReads,
 				Logs: logNames(d.Logs), Streams: d.Streams, Hears: ComposedHears(d), Queues: d.Queues,
 			})
+			// **The grants part creates what a manifest declares** (novox/hq ADR 0547 §5; the operator, 2026-10-26
+			// 08:54): every placed module's buckets, logs and streams, each by its stream's name.
+			if d.Module == GrantsModule {
+				out[len(out)-1].CreatesStreams = declaredStreamsOf(r)
+			}
 			// **The vault's holder asks the desks and the issuing providers itself** (issue 723), under the
 			// account its own runtime runs on (ADR 0259 §8's runs-as): the one module granted it.
 			if holdsSeat(d, VaultSeat) {
@@ -218,6 +231,7 @@ func Users(r Records) ([]Principal, error) {
 			var carried []Declared
 			for _, d := range r.Assigned[node] {
 				if d.RunsAs == "" && runnerServes(d) {
+					d = withNamedReaders(d)
 					// Never a restricted stream for what the tool runner carries (novox/hq ADR 0376 §1).
 					d.Hears = ComposedHears(d)
 					carried = append(carried, d)
@@ -418,3 +432,29 @@ func boundBucketsOf(r Records) []string {
 func runnerServes(d Declared) bool {
 	return d.Module == RuntimeModule || d.NoAccount || d.Loads || len(d.Serves) > 0 || len(d.Holds) > 0 || len(d.Waits) > 0 || len(d.Checks) > 0
 }
+
+// declaredStreamsOf is the stream of every bucket, log and stream a module placed anywhere declares, once each, in name
+// order (novox/hq ADR 0547 §5, issue 1790): `KV_<module>_<state>`, `LOG_<module>_<log>` and each module stream's own
+// name. What the grants part may create, and nothing beside.
+func declaredStreamsOf(r Records) []string {
+	seen := map[string]bool{}
+	for _, mods := range r.Assigned {
+		for _, d := range mods {
+			for _, b := range d.State {
+				seen["KV_"+b.Bucket()] = true
+			}
+			for _, l := range d.Logs {
+				seen[l.Stream()] = true
+			}
+			for _, s := range d.Streams {
+				seen[s.Name] = true
+			}
+		}
+	}
+	out := make([]string, 0, len(seen))
+	for s := range seen {
+		out = append(out, s)
+	}
+	sort.Strings(out)
+	return out
+}

go/buscompose/writers.go

@@ -37,6 +37,20 @@ type WriterRow struct {
 // isController, and the other writers' tests, are who a row's writer is as a principal.
 func isController(p Principal, _ string) bool { return p.Kind == KindController }
 
+// createsDeclared is the controller, or the grants part creating one stream a manifest declares, by its own name: the
+// create alone, never an update or a delete (novox/hq ADR 0547 §5; the operator, 2026-10-26 08:54).
+func createsDeclared(p Principal, pattern string) bool {
+	if isController(p, pattern) {
+		return true
+	}
+	name, ok := strings.CutPrefix(pattern, "$JS.API.STREAM.CREATE.")
+	if ok && p.Kind == KindModule && p.Module == GrantsModule && name == GrantsUserListObjectStream {
+		return true
+	}
+	return ok && p.Kind == KindModule && p.Module == GrantsModule && slices.Contains(p.CreatesStreams, name) &&
+		safeSubject.MatchString(name)
+}
+
 // ownMachine is a node writing a subject whose third token is its own name, and no wildcard there.
 func ownMachine(p Principal, pattern string) bool {
 	tokens := strings.Split(pattern, ".")
@@ -170,7 +184,8 @@ var WritersTable = []WriterRow{
 		// bucket's stream (ADR 0201), which defines nothing the mesh keeps.
 		Subjects: []string{"$JS.API.STREAM.CREATE.>", "$JS.API.STREAM.UPDATE.>", "$JS.API.STREAM.DELETE.>",
 			"$JS.API.CONSUMER.DURABLE.CREATE.>"},
-		Writes: isController},
+		Writes: createsDeclared,
+		Shared: "the grants part creates a stream a manifest declares, by its name, and never updates or deletes one (novox/hq ADR 0547 §5; the operator, 2026-10-26 08:54)"},
 	{State: "builds and their outcomes", Writer: "the build seat's holder", KeptIn: "its own state",
 		Others:   "the controller asks",
 		Subjects: []string{"mesh.seat.node-build-agent.event.built", "mesh.seat.mesh-build-machine.event.built"},
@@ -237,7 +252,10 @@ var WritersTable = []WriterRow{
 		KeptIn: "the object bucket " + DeclarationFilesBucket + "-<node> of each node, an object removed a day after the " +
 			"node's latest declaration no longer names it",
 		Others:   "a node-engine reads an object of its own bucket by its name and may neither list the bucket nor write it",
-		Subjects: []string{"$O.*.>"}, Writes: isControllerOrTheHandPath},
+		Subjects: []string{"$O.*.>"}, Writes: func(p Principal, pattern string) bool {
+			return isControllerOrTheHandPath(p, pattern) || grantsOwnObjects(p, pattern)
+		},
+		Shared: "the grants part writes its own object bucket " + GrantsUserListObjects + ", the user list sealed to the bus node, and no other (novox/hq ADR 0547 clause 7)"},
 	{State: "the declared-config mirror", Writer: "controller (lease holder), from its store, only on a change",
 		KeptIn: "key-value " + DeclaredConfigBucket, Others: "read through `reads` as mesh-controller." + MirrorDeclaredConfig,
 		Subjects: kvOf(DeclaredConfigBucket), Writes: isController},

go/catalogue/holdings_test.go

@@ -172,7 +172,7 @@ func TestAStoreRowWithoutAProtocolKeepsTheCompiledOne(t *testing.T) {
 	t.Cleanup(func() { UseSeats(was) })
 	UseSeats([]Seat{{Name: "node-build-go", Scope: ScopeNode, Decision: "row"}})
 	got, ok := SeatNamed("node-build-go")
-	if !ok || len(got.Accepts) == 0 || !got.PulledByKind {
+	if !ok || len(got.Accepts) == 0 || !got.PulledByKind || !got.Yields {
 		t.Fatalf("the Go build seat lost what it accepts when loaded from the store: %+v", got)
 	}
 	if got.Decision != "row" {

go/catalogue/runtime.go

@@ -311,6 +311,17 @@ func (r Resolution) ownRuntimes(with Rendering) ([]map[string]any, error) {
 		if words, err = r.readsWords(m, words, with); err != nil {
 			return nil, err
 		}
+		// A build seat's holder gives way on its node, and its steps are told their part of the node's share
+		// (novox/hq ADR 0553).
+		yielding, yieldWords := r.yieldsOf(m, with)
+		if len(yieldWords) > 0 {
+			if words == nil {
+				words = map[string]string{}
+			}
+			for k, v := range yieldWords {
+				words[k] = v
+			}
+		}
 		if len(words) > 0 {
 			body, err := json.Marshal(map[string]map[string]string{m.Module: words})
 			if err != nil {
@@ -329,6 +340,9 @@ func (r Resolution) ownRuntimes(with Rendering) ([]map[string]any, error) {
 			process[HealthField] = m.RuntimeHealth
 			healthInto(process, m, with)
 		}
+		if yielding != nil {
+			process["yields"] = yielding
+		}
 		if err := artifactsInto(process, RuntimeModule, with); err != nil {
 			return nil, err
 		}

go/catalogue/runtime_test.go

@@ -498,6 +498,54 @@ func TestAModuleOfItsOwnAccountIsServedByARuntimeOfItsOwn(t *testing.T) {
 	if _, told := env[RuntimeOperatorAccount]; told {
 		t.Error("a runtime of a module's own account is told the operator's account")
 	}
+	if _, yields := own["yields"]; yields {
+		t.Errorf("telegram holds no build seat and yields: %v", own["yields"])
+	}
+	// The build seats' holders yield (ADR 0553): idle, under the node's one share from the node-engine's build-cpu-share,
+	// and their steps are told it.
+	builder := func(name, seat string) Manifest {
+		b := aToolsModule(t, name, "tools/index.js")
+		b.RunsAs, b.SecretsOwner = name, name
+		b.OwnSecrets = OwnSecrets{"broker": {Path: "/var/lib/" + name + "/broker"}}
+		b.Claims = []Claim{{Name: seat}}
+		return b
+	}
+	gob, img := builder("gob", "node-build-go"), builder("img", "node-build-image")
+	with.Needed["gob"], with.Needed["img"] = map[string]string{"broker": "own"}, map[string]string{"broker": "own"}
+	for _, c := range []struct {
+		settings SettingsBy
+		share    string
+	}{
+		{nil, "50"},
+		{SettingsBy{"mesh-host": {{From: "anchor", Values: map[string]any{"build-cpu-share": float64(75)}}}}, "75"},
+		{SettingsBy{"mesh-host": {{From: "anchor", Values: map[string]any{"build-cpu-share": float64(0)}}}}, "50"},
+	} {
+		with.Settings = c.settings
+		runtimes, err := Resolution{Node: "anchor", Modules: []Manifest{gob, img, telegram, goRuntime}}.ownRuntimes(with)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(runtimes) != 3 {
+			t.Fatalf("%d runtimes of their own, want gob's, img's and telegram's", len(runtimes))
+		}
+		for _, p := range runtimes {
+			name := fmt.Sprint(p["name"])
+			words := map[string]map[string]string{}
+			_ = json.Unmarshal([]byte(p["env"].(map[string]string)[RuntimeToolEnv]), &words)
+			mod := strings.TrimSuffix(name, "-runtime")
+			if mod == "telegram" {
+				if p["yields"] != nil || words[mod]["MESH_BUILD_CPU_SHARE"] != "" {
+					t.Errorf("telegram yields under %v: %v %v", c.settings, p["yields"], words)
+				}
+				continue
+			}
+			if got := fmt.Sprint(p["yields"]); got != "map[cpu-share:"+c.share+" priority:idle]" ||
+				words[mod]["MESH_BUILD_CPU_SHARE"] != c.share {
+				t.Errorf("%s under %v yields %s with words %v; want share %s", name, c.settings, got, words[mod], c.share)
+			}
+		}
+	}
+	with.Settings = nil
 	// Without the machine's runtime to run it from, it is refused in words.
 	if _, err := (Resolution{Node: "anchor", Modules: []Manifest{telegram}}).ownRuntimes(with); err == nil {
 		t.Error("a module of its own account composed without a runtime program")

go/catalogue/seats.go

@@ -49,6 +49,11 @@ type Seat struct {
 	// order Accepts lists them (novox/hq ADR 0525 §2, ADR 0536 §4): the build seats'. Compiled, never stored, like
 	// Receives.
 	PulledByKind bool
+	// Yields says the seat's holder gives way to everything else on its node (novox/hq ADR 0553): its runtime runs at
+	// idle priority in the node's one yielding slice, under the node's one processor share (buildcpu.ShareSetting) that
+	// every yielding holder of the node shares. The build seats': a build must never slow the operator's desktop.
+	// Compiled, never stored, like Receives.
+	Yields bool
 	// Serves carries each verb in full — name, description, schema — because a role's tools are the
 	// mesh's to define and an agent's to call (novox/hq ADR 0132, design 33 §2).
 	Serves []Verb
@@ -256,11 +261,11 @@ var defaultSeats = append([]Seat{
 	// its holder taking nothing, kept on the module's own pause key (issue 1887's design limit 2). They replace
 	// node-build-agent, retired with build-agent (ADR 0524 §5).
 	{Name: "node-build-go", Scope: ScopeNode, Accepts: buildAskKinds(), PulledByKind: true, Serves: buildSeatVerbs("Go"),
-		Decision: "novox/hq ADR 0525, ADR 0536"},
+		Yields: true, Decision: "novox/hq ADR 0525, ADR 0536, ADR 0553"},
 	{Name: "node-build-node", Scope: ScopeNode, Accepts: buildAskKinds(), PulledByKind: true, Serves: buildSeatVerbs("Node"),
-		Decision: "novox/hq ADR 0525, ADR 0536"},
+		Yields: true, Decision: "novox/hq ADR 0525, ADR 0536, ADR 0553"},
 	{Name: "node-build-image", Scope: ScopeNode, Accepts: buildAskKinds(), PulledByKind: true, Serves: buildSeatVerbs("image"),
-		Decision: "novox/hq ADR 0525, ADR 0536"},
+		Yields: true, Decision: "novox/hq ADR 0525, ADR 0536, ADR 0553"},
 	// **The mesh's resolvers** (novox/hq ADR 0194, 0196, 0223): every node's internal domain, and
 	// every node and container asks them and nothing else. Replicated since ADR 0223: held on more
 	// than one machine, each answering the same names from the same roster, and every machine's
@@ -497,6 +502,7 @@ func UseSeats(s []Seat) {
 			row.Paths = d.Paths
 			row.Replicated = d.Replicated
 			row.PulledByKind = d.PulledByKind
+			row.Yields = d.Yields // never stored (ADR 0553)
 			row.Serves = optionalAsCompiled(row.Serves, d.Serves)
 		}
 		merged = append(merged, row)

go/catalogue/seats_test.go

@@ -324,6 +324,9 @@ func TestNodeBuildAgentIsRetiredForTheBuildSeats(t *testing.T) {
 		if !ok || s.Scope != ScopeNode || !s.PulledByKind || strings.Join(s.Accepts, ",") != "delivery,check,recheck" {
 			t.Fatalf("%s = %+v", name, s)
 		}
+		if !s.Yields {
+			t.Errorf("%s does not yield (ADR 0553)", name)
+		}
 		var verbs []string
 		for _, v := range s.Serves {
 			verbs = append(verbs, v.Name)
@@ -332,4 +335,14 @@ func TestNodeBuildAgentIsRetiredForTheBuildSeats(t *testing.T) {
 			t.Errorf("%s serves %v", name, verbs)
 		}
 	}
+	// The build seats are the seats that yield, and no other (ADR 0553 §1).
+	var yielding []string
+	for _, s := range Seats() {
+		if s.Yields {
+			yielding = append(yielding, s.Name)
+		}
+	}
+	if strings.Join(yielding, ",") != "node-build-go,node-build-node,node-build-image" {
+		t.Errorf("the seats that yield are %v", yielding)
+	}
 }

go/catalogue/yields.go

@@ -0,0 +1,69 @@
+package catalogue
+
+import (
+	"strconv"
+
+	"git.novox.be/novox/mesh-sdk/go/buildcpu"
+)
+
+// yieldsOf is how the runtime of its own a module is served by gives way on this node (novox/hq ADR 0553), or nil when
+// it does not, and the word its steps size their threads from:
+//
+//   - a module holding a seat that yields (Seat.Yields, the build seats) runs at idle priority under the node's one share
+//     of its processors: the node-engine's own config build-cpu-share (buildcpu.ShareSetting) as this node's layers give
+//     it, its default where none does. Every yielding module of the node carries the same share, so the node-engine's
+//     one yielding slice has one quota (ADR 0553 §2, §3).
+//   - its word: that share (buildcpu.ShareWord), which a step divides by its own module's capacity (ADR 0553 §4).
+//
+// Never a refusal: a share out of range is the default, so a mistyped value bounds the builds at the default and never
+// stops the node's whole composition.
+func (r Resolution) yieldsOf(m Manifest, with Rendering) (map[string]any, map[string]string) {
+	if !yields(m) {
+		return nil, nil
+	}
+	engine := Manifest{Module: engineModule}
+	for _, e := range r.Modules {
+		if e.Module == engineModule {
+			engine = e
+		}
+	}
+	share := buildcpu.DefaultPercent
+	for _, s := range Effective(engine, with.Settings[engineModule]) {
+		if s.Key == buildcpu.ShareSetting {
+			if n, ok := percentOf(s.Value); ok {
+				share = n
+			}
+		}
+	}
+	return map[string]any{"priority": "idle", "cpu-share": share},
+		map[string]string{buildcpu.ShareWord: strconv.Itoa(share)}
+}
+
+// yields is whether a module claims a seat that yields.
+func yields(m Manifest) bool {
+	for _, c := range m.Claims {
+		if s, ok := SeatNamed(c.Name); ok && s.Yields {
+			return true
+		}
+	}
+	return false
+}
+
+// percentOf is a setting's value as a percent from 1 to 100: a number, or a string holding one.
+func percentOf(v any) (int, bool) {
+	var n int
+	switch x := v.(type) {
+	case float64:
+		n = int(x)
+	case int:
+		n = x
+	case string:
+		var err error
+		if n, err = strconv.Atoi(x); err != nil {
+			return 0, false
+		}
+	default:
+		return 0, false
+	}
+	return n, n >= 1 && n <= 100
+}

go/declaration/declaration.go

@@ -916,6 +916,56 @@ type Process struct {
 	// Health is how this resource is ready (novox/hq ADR 0240 rule 2, Phase B): one kind and its
 	// timing, judged by the node-engine beside liveness. Absent: judged alive or not, and nothing more.
 	Health *Health `json:"health,omitempty"`
+
+	// Yields says this process gives way to everything else on its machine (novox/hq ADR 0553, issue 1806): the
+	// runtime of a build seat's holder, whose builds must never slow the operator's desktop. Absent: the machine's
+	// defaults. For a process that stays up.
+	Yields *Yields `json:"yields,omitempty"`
+}
+
+// YieldIdle is the one priority a process yields at: the lowest there is.
+const YieldIdle = "idle"
+
+// YieldSlice is the one slice the node-engine places every yielding process of its node in (novox/hq ADR 0553 §2): a
+// slice at the top of the hierarchy, beside the operator's user slice and the system's, so its idle weight and its
+// quota bind against everything else on the machine. No dash in its name: a dash makes a slice a child of the slice
+// named before it, where its weight would count only against its siblings.
+const YieldSlice = "meshyield.slice"
+
+// Yields is how a process gives way, written by the node-engine (novox/hq ADR 0553).
+//
+// **Priority** "idle": the process runs in YieldSlice, whose CPUWeight is idle (it runs only on cycles nothing else
+// wants) and whose IOWeight is 1, with Nice=19 and the lowest best-effort IO level for every process it starts. The IO
+// controls bind only where the disk's scheduler honours them (bfq, or io.cost for the weight); under `none`, the
+// usual one for NVMe, they do nothing, and the CPU bound is what holds. **CPUShare** is the most of the machine's
+// processors the slice may take, in percent, shared by every yielding process of the node together: the node-engine
+// writes it as the slice's CPUQuota for the processors the machine has, so the bound is the kernel's. Every yielding
+// process of one node carries the same share: the composer gives the node's one value (ADR 0553 §3). 0 is no cap.
+type Yields struct {
+	Priority string `json:"priority,omitempty"`
+	CPUShare int    `json:"cpu-share,omitempty"`
+}
+
+func (y *Yields) problems(where string, staysUp bool) []string {
+	if y == nil {
+		return nil
+	}
+	var problems []string
+	if !staysUp {
+		problems = append(problems, where+": yields is for a process that stays up")
+	}
+	switch y.Priority {
+	case "", YieldIdle:
+	default:
+		problems = append(problems, fmt.Sprintf("%s: yields priority %q is not one this host knows: idle", where, y.Priority))
+	}
+	if y.CPUShare < 0 || y.CPUShare > 100 {
+		problems = append(problems, fmt.Sprintf("%s: yields cpu-share %d is not a percent of the machine, 0 to 100", where, y.CPUShare))
+	}
+	if y.Priority == "" && y.CPUShare == 0 {
+		problems = append(problems, where+": yields says neither a priority nor a cpu-share")
+	}
+	return problems
 }
 
 func (d *Process) Identity() string { return d.ID }
@@ -948,6 +998,7 @@ func ProcessNameProblem(name string) string {
 
 func (d *Process) validate(where string, _ bool) []string {
 	problems := d.Health.problems(where, false, !d.RunOnce && d.Schedule == "")
+	problems = append(problems, d.Yields.problems(where, !d.RunOnce && d.Schedule == "")...)
 	if problem := ProcessNameProblem(d.Name); problem != "" {
 		problems = append(problems, where+": "+problem)
 	}

go/declaration/process_test.go

@@ -92,6 +92,20 @@ func TestTheModesAreExclusive(t *testing.T) {
 	if problems := watching.validate("a process", false); len(problems) == 0 {
 		t.Fatal("a scheduled process was given something to restart on, and it is never running")
 	}
+
+	// A process yields only while it stays up, at a priority the host knows, within the machine (issue 1806).
+	for name, bad := range map[string]func(*Process){
+		"a step that yields":     func(p *Process) { p.RunOnce = true; p.Yields = &Yields{Priority: YieldIdle} },
+		"an unknown priority":    func(p *Process) { p.Yields = &Yields{Priority: "low"} },
+		"a share over the whole": func(p *Process) { p.Yields = &Yields{CPUShare: 150} },
+		"a yield saying nothing": func(p *Process) { p.Yields = &Yields{} },
+	} {
+		p := aProcess()
+		bad(p)
+		if problems := p.validate("a process", false); len(problems) == 0 {
+			t.Errorf("%s was accepted", name)
+		}
+	}
 }
 
 // A cadence that is not a cadence is refused near its author, rather than by a machine at the far
@@ -118,6 +132,11 @@ func TestEachModeOnItsOwnIsAccepted(t *testing.T) {
 	if problems := every.validate("a process", false); len(problems) != 0 {
 		t.Fatalf("a scheduled process was refused: %v", problems)
 	}
+	yielding := aProcess()
+	yielding.Yields = &Yields{Priority: YieldIdle, CPUShare: 50}
+	if problems := yielding.validate("a process", false); len(problems) != 0 {
+		t.Fatalf("a daemon yielding at idle under half the machine was refused: %v", problems)
+	}
 }
 
 // **The one that cannot be escaped, only refused.**

go/delivery/buildrun/asks_test.go

@@ -2,11 +2,15 @@ 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 {
@@ -48,6 +52,74 @@ func TestAnAskerPutsOnceAndReadsTheStep(t *testing.T) {
 	if len(g.Asks()) != 0 {
 		t.Fatal("a wait put an ask")
 	}
+	// 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)
+	}
+	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
@@ -69,3 +141,26 @@ func TestARedeliveryToTheSameNodeRestartsTheBound(t *testing.T) {
 		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) }

go/delivery/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, ", "))
+}

go/delivery/checker.go

@@ -115,6 +115,10 @@ type Composition struct {
 	Words    string   `json:"words,omitempty"`
 	SDK      string   `json:"sdk,omitempty"`
 	Machines []string `json:"machines,omitempty"`
+	// FPSet is the candidate's fingerprint set (Candidate.FPSet) the composition judged: a carry keeps a composition that
+	// passed while the candidate's set is the same, and composes again when a fingerprint changed (novox/hq ADR 0548 §5).
+	// Absent in a value written before it, which a carry composes again.
+	FPSet string `json:"fpset,omitempty"`
 }
 
 // Took is the time of each part of a check in integer milliseconds (ADR 0447 clause 3): waiting in the queue, cloning,
@@ -139,16 +143,25 @@ type FailedFirst struct {
 	Words   string `json:"words,omitempty"`
 }
 
+// MaxFailures is the most entries a verdict's Failures holds (issue 1921): fifty tests named one by one, and an entry
+// after them saying how many more failed.
+const MaxFailures = 50
+
 // Verdict is the value of a verdict key: the group and its heads hash, the trunk head of each repository it was judged
 // against (repository to full sha), the State (running, pass or fail), what failed first, the tests run and kept per
 // level, each part's time, the machines composed and the mesh-sdk version the composition ran with (ADR 0446 clause 5).
 type Verdict struct {
-	V        int                    `json:"v"`
-	Group    string                 `json:"group"`
-	Heads    string                 `json:"heads"`
-	Trunk    map[string]string      `json:"trunk,omitempty"`
-	State    string                 `json:"state"`
-	Failed   FailedFirst            `json:"failed,omitzero"`
+	V      int               `json:"v"`
+	Group  string            `json:"group"`
+	Heads  string            `json:"heads"`
+	Trunk  map[string]string `json:"trunk,omitempty"`
+	State  string            `json:"state"`
+	Failed FailedFirst       `json:"failed,omitzero"`
+	// Failures names every test that failed, in the order judged, each with the first line of its words (issue 1921):
+	// Failed keeps the first one's words whole, and a check that ran every test says all it found here. At most
+	// MaxFailures entries, the last of a longer list saying how many more failed. Absent in a value written before it,
+	// and from a verdict whose failure is no test.
+	Failures []FailedFirst          `json:"failures,omitempty"`
 	Levels   map[string]LevelResult `json:"levels,omitempty"`
 	Took     Took                   `json:"took,omitzero"`
 	Machines []string               `json:"machines,omitempty"`
@@ -157,6 +170,14 @@ type Verdict struct {
 	Composition *Composition `json:"composition,omitempty"`
 	// OverBound names the levels whose running went over their bound; it does not change the State (ADR 0453 clause 9).
 	OverBound []string `json:"over-bound,omitempty"`
+	// Beside is the commit of each sibling repository the check read beside the repositories it merged (ADR 0484 §4), by
+	// repository: a move of one puts the verdict out of date as a trunk move does, and it is carried (novox/hq ADR 0548 §6).
+	// A repository is in Trunk or here, never both. Absent in a value written before it.
+	Beside map[string]string `json:"beside,omitempty"`
+	// CarriedFrom names, of a carried verdict, the trunk and sibling commits it was judged on before the moves it was
+	// carried over, by repository (ADR 0548 §5): the verdict was rewritten for Trunk and Beside by running only the packages
+	// whose digest the moves changed. Absent from a verdict judged whole, and from one still running.
+	CarriedFrom map[string]string `json:"carried-from,omitempty"`
 }
 
 func (c *Composition) check() error {
@@ -194,6 +215,33 @@ func (v Verdict) check() error {
 			return fmt.Errorf("delivery: the verdict's trunk head of %s is empty", repository)
 		}
 	}
+	for repository, commit := range v.Beside {
+		if commit == "" {
+			return fmt.Errorf("delivery: the verdict's sibling commit of %s is empty", repository)
+		}
+		if _, ok := v.Trunk[repository]; ok {
+			return fmt.Errorf("delivery: the verdict names %s as a trunk it merged and as a sibling it read", repository)
+		}
+	}
+	if len(v.CarriedFrom) > 0 {
+		if v.State == VerdictRunning {
+			return fmt.Errorf("delivery: a running verdict is carried from nothing: carried-from is written with its end")
+		}
+		moved := false
+		for repository, commit := range v.CarriedFrom {
+			now, inTrunk := v.Trunk[repository]
+			if !inTrunk {
+				now = v.Beside[repository]
+			}
+			if commit == "" || now == "" {
+				return fmt.Errorf("delivery: the verdict's carried-from names %s, which it judged on no commit of", repository)
+			}
+			moved = moved || commit != now
+		}
+		if !moved {
+			return fmt.Errorf("delivery: the verdict's carried-from names the commits it is judged on: nothing moved, so nothing was carried")
+		}
+	}
 	for level, r := range v.Levels {
 		if err := checkLevel(level); err != nil {
 			return err
@@ -222,6 +270,12 @@ func (v Verdict) check() error {
 		}
 	}
 	named := v.Failed.Test != "" || v.Failed.Machine != ""
+	if len(v.Failures) > 0 && v.State != VerdictFail {
+		return fmt.Errorf("delivery: a %s verdict names no failures", v.State)
+	}
+	if len(v.Failures) > MaxFailures+1 {
+		return fmt.Errorf("delivery: the verdict names %d failures, more than %d and the count of the rest", len(v.Failures), MaxFailures)
+	}
 	switch v.State {
 	case VerdictRunning:
 		if v.Failed != (FailedFirst{}) {

go/delivery/checker_test.go

@@ -3,6 +3,7 @@ package delivery
 import (
 	"encoding/json"
 	"errors"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -28,7 +29,12 @@ func verdictSamples() map[string]Verdict {
 	failTest.Levels = map[string]LevelResult{LevelUnit: {Run: 1}}
 	failMachine := passVerdict()
 	failMachine.State, failMachine.Failed = VerdictFail, FailedFirst{Machine: "ace", Words: "path /etc/x is owned by two modules"}
-	return map[string]Verdict{"running": running, "pass": passVerdict(), "fail by a test": failTest, "fail by a machine": failMachine}
+	carried := passVerdict()
+	carried.Beside = map[string]string{"novox/mesh-catalog": "cccc"}
+	carried.CarriedFrom = map[string]string{"novox/mesh-sdk": "9999", "novox/mesh-control": "bbbb", "novox/mesh-catalog": "cccc"}
+	carried.Composition = &Composition{State: CompositionPass, SDK: carried.SDK, Machines: []string{"ace"}, FPSet: "fps1:00"}
+	return map[string]Verdict{"running": running, "pass": passVerdict(), "fail by a test": failTest, "fail by a machine": failMachine,
+		"carried": carried}
 }
 
 func keptSample() Kept {
@@ -247,7 +253,14 @@ func TestVerdictCarriesSkippedCompositionAndOverBound(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	for _, field := range []string{`"skipped":4`, `"composition":{"state":"pass"`, `"over-bound":["integration"]`} {
+	v.Beside, v.CarriedFrom = map[string]string{"novox/mesh-catalog": "cccc"}, map[string]string{"novox/mesh-catalog": "cbcb"}
+	v.Composition.FPSet = "fps1:ab"
+	data, err = EncodeVerdict(v)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, field := range []string{`"skipped":4`, `"composition":{"state":"pass"`, `"over-bound":["integration"]`, `"beside":{"novox/mesh-catalog":"cccc"}`,
+		`"carried-from":{"novox/mesh-catalog":"cbcb"}`, `"fpset":"fps1:ab"`} {
 		if !strings.Contains(string(data), field) {
 			t.Errorf("the value lacks %s: %s", field, data)
 		}
@@ -294,6 +307,13 @@ func TestVerdictNewFieldsChecked(t *testing.T) {
 		"a not-run composition naming machines": {func(v *Verdict) { v.Composition = &Composition{State: CompositionNotRun, Machines: []string{"ace"}} }, []string{"composition", "not run"}},
 		"an unknown over-bound level":           {func(v *Verdict) { v.OverBound = []string{"e2e"} }, []string{"e2e"}},
 		"an over-bound level named twice":       {func(v *Verdict) { v.OverBound = []string{LevelUnit, LevelUnit} }, []string{"over-bound", "unit"}},
+		// ADR 0548 §5, §6: the siblings read and the commits a verdict was carried from.
+		"a sibling with no commit":      {func(v *Verdict) { v.Beside = map[string]string{"novox/mesh-catalog": ""} }, []string{"sibling", "mesh-catalog"}},
+		"a trunk named as a sibling":    {func(v *Verdict) { v.Beside = map[string]string{"novox/mesh-sdk": "aaaa"} }, []string{"trunk", "sibling", "mesh-sdk"}},
+		"carried from an unjudged repo": {func(v *Verdict) { v.CarriedFrom = map[string]string{"novox/other": "1111"} }, []string{"carried-from", "novox/other"}},
+		"carried from an empty commit":  {func(v *Verdict) { v.CarriedFrom = map[string]string{"novox/mesh-sdk": ""} }, []string{"carried-from", "mesh-sdk"}},
+		"carried over no move":          {func(v *Verdict) { v.CarriedFrom = map[string]string{"novox/mesh-sdk": "aaaa"} }, []string{"nothing moved"}},
+		"a running verdict carried":     {func(v *Verdict) { v.State, v.CarriedFrom = VerdictRunning, map[string]string{"novox/mesh-sdk": "9999"} }, []string{"running", "carried"}},
 	}
 	for name, c := range cases {
 		v := passVerdict()
@@ -318,7 +338,7 @@ func TestVerdictOldAndNewReadersAgree(t *testing.T) {
 	if err != nil {
 		t.Fatalf("the new reader of an old value: %v", err)
 	}
-	if v.Composition != nil || v.OverBound != nil || v.Levels[LevelUnit].Skipped != 0 || v.Levels[LevelUnit].Run != 12 {
+	if v.Composition != nil || v.OverBound != nil || v.Beside != nil || v.CarriedFrom != nil || v.Levels[LevelUnit].Skipped != 0 || v.Levels[LevelUnit].Run != 12 {
 		t.Errorf("an old value grew fields: %+v", v)
 	}
 	again, err := EncodeVerdict(v)
@@ -329,6 +349,9 @@ func TestVerdictOldAndNewReadersAgree(t *testing.T) {
 	n.Levels[LevelUnit] = LevelResult{Run: 12, Kept: 301, Skipped: 4}
 	n.Composition = &Composition{State: CompositionNotRun}
 	n.OverBound = []string{LevelUnit}
+	n.Beside = map[string]string{"novox/mesh-catalog": "cccc"}
+	n.CarriedFrom = map[string]string{"novox/mesh-sdk": "9999"}
+	n.Composition.FPSet = "fps1:00"
 	data, err := EncodeVerdict(n)
 	if err != nil {
 		t.Fatal(err)
@@ -600,3 +623,38 @@ func TestPreviewOfAHeadInConflict(t *testing.T) {
 		t.Errorf("the old reader: %+v %v", old, err)
 	}
 }
+
+// Issue 1921: a failed verdict names every failed test in Failures and reads back the same; an older reader's value
+// without it reads too; Failures on a verdict that is no fail, and more than MaxFailures and the count of the rest, are
+// refused.
+func TestVerdictNamesEveryFailure(t *testing.T) {
+	v := passVerdict()
+	v.State = VerdictFail
+	v.Failed = FailedFirst{Test: "integration: x/a.TestA", Words: "a_test.go:9: want 1, got 2\nmore"}
+	v.Failures = []FailedFirst{{Test: "integration: x/a.TestA", Words: "a_test.go:9: want 1, got 2"}, {Test: "integration: x/b.TestB", Words: "b_test.go:3: boom"}}
+	data, err := EncodeVerdict(v)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := DecodeVerdict(data)
+	v.V = Version
+	if err != nil || !SameVerdict(got, v) || !strings.Contains(string(data), `"failures":[{"test":"integration: x/a.TestA"`) {
+		t.Fatalf("%s: %+v %v", data, got, err)
+	}
+	old := strings.Replace(string(data), string(data[strings.Index(string(data), `,"failures":`):strings.Index(string(data), `,"levels":`)]), "", 1)
+	if got, err := DecodeVerdict([]byte(old)); err != nil || len(got.Failures) != 0 || got.Failed != v.Failed {
+		t.Fatalf("a value without failures: %+v %v (%s)", got, err, old)
+	}
+	p := passVerdict()
+	p.Failures = v.Failures
+	if _, err := EncodeVerdict(p); err == nil {
+		t.Error("a pass with failures was written")
+	}
+	v.Failures = make([]FailedFirst, MaxFailures+2)
+	for i := range v.Failures {
+		v.Failures[i] = FailedFirst{Test: "unit: x.T" + strconv.Itoa(i)}
+	}
+	if _, err := EncodeVerdict(v); err == nil {
+		t.Error("a verdict naming more than MaxFailures and the rest was written")
+	}
+}

go/delivery/delivery.go

@@ -34,9 +34,12 @@
 // **The release 4 layouts** (issues 1356 to 1359; ADR 0453 clauses 4, 6 and 16): the new fingerprint form (fingerprint2.go),
 // the indexer's manifests by digest and the new fields of its modules and candidates (manifests.go, source.go), the
 // builder's build keys (builder.go) and the checker's verdicts and kept verdicts (checker.go). A manifests value is the
-// one exception to the size above: a manifest is up to about 21 KB, whole, byte for byte.
+// one exception to the size above: a manifest is up to about 21 KB, whole, byte for byte. The bus module's have on the
+// node holding mesh-broker is the other: its user list's handing carries a sealed box of every loaded user's hash, some
+// kilobytes (handed.go).
 //
-// Standard library only, and this module's own asks and declaration packages (a composition holds declaration resources).
+// Standard library only, and this module's own asks, declaration and seal packages (a composition holds declaration
+// resources; the adoption handing is a sealed box, handed.go).
 package delivery
 
 import (
@@ -352,6 +355,18 @@ type UserListWritten struct {
 	Users  int       `json:"users"`
 	At     time.Time `json:"at"`
 	Error  string    `json:"error,omitempty"`
+	// Follows is which list the node follows now (FollowController or FollowGrants, novox/hq ADR 0547 clause 8), empty
+	// from a node-engine before the switch.
+	Follows string `json:"follows,omitempty"`
+	// Key is the bus node's sealing key, its public half as SPKI PEM: the key the grants part seals its list to
+	// (clause 7). Public, as the vault holds it.
+	Key string `json:"key,omitempty"`
+	// Unwatched says why the bus node does not watch the grants part's key now (its watch refused or ended, and tried
+	// again), empty while it does or where it need not (ADR 0547 clause 8): it then keeps the last list it followed.
+	Unwatched string `json:"unwatched,omitempty"`
+	// Handed is the hashes of the users of the list on the machine, sealed to the vault, for its adoption of the
+	// accounts it holds no value for (ADR 0547 clause 9, handed.go); nil while the vault's key is not known.
+	Handed *AccountsHanded `json:"handed,omitempty"`
 }
 
 // HaveNode is a node's own facts, written under HaveNodeKey. Each field is the node-engine's own JSON, carried whole:
@@ -502,7 +517,8 @@ func SameHave(a, b Have) bool {
 	}
 	x, y := *ua, *ub
 	x.At, y.At = time.Time{}, time.Time{}
-	return x == y && ua.At.Equal(ub.At)
+	x.Handed, y.Handed = nil, nil
+	return x == y && ua.At.Equal(ub.At) && sameHanded(ua.Handed, ub.Handed)
 }
 
 // SameHaveNode says whether two node facts are the same value, comparing each carried JSON without its spacing.

go/delivery/delivery_test.go

@@ -1,12 +1,15 @@
 package delivery
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"reflect"
 	"strings"
 	"testing"
 	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/seal"
 )
 
 // 1131/AC1: the have key forms and parses back; bad names are refused, naming them.
@@ -167,6 +170,108 @@ func TestRoundTrip(t *testing.T) {
 		if !reflect.DeepEqual(out, in) || !out.UserList.At.Equal(at) {
 			t.Fatalf("got %+v want %+v", out, in)
 		}
+		// And with the hashes handed to the vault (ADR 0547 clause 9): sealed to its key, opened by it alone, every
+		// listed user with a bcrypt hash once, and refused to another key.
+		hash := "$2a$11$" + strings.Repeat("a", 53)
+		list := []byte("{ user: \"controller\", password: \"" + hash + "\", permissions: {\n" +
+			"{ user: \"node.ace\", password: \"" + hash + "\", permissions: {\n" +
+			"{ user: \"controller\", password: \"" + hash + "\" }\n{ user: \"nkey\", password: \"plain\" }\n")
+		accounts := HandedAccountsOf(list)
+		if len(accounts) != 2 || accounts[0].User != "controller" || accounts[1].User != "node.ace" || accounts[1].Hash != hash {
+			t.Fatalf("handed accounts: %+v", accounts)
+		}
+		vault, err := seal.GenerateKeyPair()
+		if err != nil {
+			t.Fatal(err)
+		}
+		other, _ := seal.GenerateKeyPair()
+		handed, err := HandAccounts(accounts, vault.PublicKey, "sha256:ab", at)
+		if err != nil {
+			t.Fatal(err)
+		}
+		in.UserList.Handed = &handed
+		b, err = EncodeHave(in)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if strings.Contains(string(b), "node.ace") || strings.Contains(string(b), hash) {
+			t.Fatalf("a user or a hash is in the clear: %s", b)
+		}
+		out, err = DecodeHave(b)
+		if err != nil || !SameHave(out, in) {
+			t.Fatalf("handed round trip: %v %+v", err, out.UserList)
+		}
+		opened, err := OpenHanded(*out.UserList.Handed, vault.PublicKey, vault.PrivateKey)
+		if err != nil || !reflect.DeepEqual(opened, accounts) {
+			t.Fatalf("opened %+v, %v", opened, err)
+		}
+		if _, err := OpenHanded(*out.UserList.Handed, other.PublicKey, other.PrivateKey); err == nil {
+			t.Fatal("a handing opened for another key")
+		}
+		if _, err := HandAccounts(accounts, "", "sha256:ab", at); err == nil {
+			t.Fatal("handed with no vault key")
+		}
+	})
+	// The grants part's list sealed to the bus node (novox/hq ADR 0547 clause 7): the key's value round-trips and refuses
+	// what the bus node could not follow, and the object opens with the node's key alone, to the digest the key names.
+	t.Run("the grants part's sealed user list", func(t *testing.T) {
+		in := Have{FP: "f1", Phase: PhaseRunning, Health: HealthOK, UserList: &UserListWritten{Source: GrantsUserListSource,
+			Revision: 3, Wanted: "sha256:ab", Digest: "sha256:ab", Users: 2, Follows: FollowGrants, Key: "PEM"}}
+		b, err := EncodeHave(in)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if out, err := DecodeHave(b); err != nil || out.UserList.Follows != FollowGrants || out.UserList.Key != "PEM" {
+			t.Fatalf("got %+v, %v", out.UserList, err)
+		}
+		list := []byte("accounts { MESH { users = [ { user: \"controller\" } ] } }\n")
+		digest := UserListDigest(list)
+		node, err := seal.GenerateKeyPair()
+		if err != nil {
+			t.Fatal(err)
+		}
+		other, _ := seal.GenerateKeyPair()
+		g := GrantsUserList{Follow: FollowGrants, Digest: digest, Object: UserListObjectName(digest),
+			SealedTo: SealingKeyID(node.PublicKey), Node: "novox", Revision: 1, Users: 1}
+		raw, err := EncodeGrantsUserList(g)
+		if err != nil {
+			t.Fatal(err)
+		}
+		back, err := DecodeGrantsUserList(raw)
+		if err != nil || back.Digest != digest || back.LeftOut == nil || back.Follow != FollowGrants {
+			t.Fatalf("decoded %+v, %v", back, err)
+		}
+		for _, bad := range []GrantsUserList{{Follow: "both", Digest: digest, Object: g.Object},
+			{Follow: FollowGrants, Digest: digest, Object: "other"}, {Follow: FollowGrants, Digest: "md5:x", Object: "md5:x"}} {
+			if _, err := EncodeGrantsUserList(bad); err == nil {
+				t.Errorf("%+v was written", bad)
+			}
+		}
+		if _, err := EncodeGrantsUserList(GrantsUserList{Follow: FollowController}); err != nil {
+			t.Errorf("a switch with no list yet refused: %v", err)
+		}
+		object, err := SealUserList(list, node.PublicKey)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if bytes.Contains(object, []byte("controller")) {
+			t.Fatal("the object carries the list in the clear")
+		}
+		opener := func(priv string) func(seal.Box) ([]byte, error) {
+			return func(b seal.Box) ([]byte, error) { s, err := seal.Open(b, priv); return []byte(s), err }
+		}
+		if got, err := OpenUserList(object, digest, opener(node.PrivateKey)); err != nil || !bytes.Equal(got, list) {
+			t.Fatalf("opened %q, %v", got, err)
+		}
+		if _, err := OpenUserList(object, digest, opener(other.PrivateKey)); err == nil {
+			t.Error("another key opened the list")
+		}
+		if _, err := OpenUserList(object, "sha256:00", opener(node.PrivateKey)); err == nil {
+			t.Error("a list of another digest was taken")
+		}
+		if _, err := SealUserList(list, "not a key"); err == nil {
+			t.Error("a list was sealed to no key")
+		}
 	})
 	t.Run("have node", func(t *testing.T) {
 		in := HaveNode{Windows: json.RawMessage(`{"a":1}`), Busy: json.RawMessage(`true`)}
@@ -306,6 +411,20 @@ func TestSame(t *testing.T) {
 	if SameHave(ua, ub) {
 		t.Error("different user lists same")
 	}
+	// A handing is compared by what it says: one said and one not differ, as do two to other keys.
+	ub.UserList.Revision = 1
+	ua.UserList.Handed = &AccountsHanded{From: "sha256:a", To: "sha256:k", Users: 2, At: at}
+	if SameHave(ua, ub) {
+		t.Error("a handing said and one not are the same")
+	}
+	ub.UserList.Handed = &AccountsHanded{From: "sha256:a", To: "sha256:k", Users: 2, At: at.In(time.Local)}
+	if !SameHave(ua, ub) {
+		t.Error("equal handings differ")
+	}
+	ub.UserList.Handed.To = "sha256:j"
+	if SameHave(ua, ub) {
+		t.Error("handings to other keys same")
+	}
 	n := HaveNode{V: 1, Busy: json.RawMessage(`true`)}
 	if !SameHaveNode(n, HaveNode{V: 1, Busy: json.RawMessage(`true`)}) || SameHaveNode(n, HaveNode{V: 1}) {
 		t.Error("have node")

go/delivery/gate_test.go

@@ -123,6 +123,15 @@ func sampleMerge() Merge {
 	}}
 }
 
+func sampleTurn() Turn {
+	at := time.Date(2026, 10, 26, 9, 0, 0, 0, time.UTC)
+	return Turn{Repository: "novox/mesh-sdk", Waiting: []TurnWait{
+		{Group: "feat/x", Heads: mustHash(gateHeads()), Ask: "merge.feat/x." + mustHash(gateHeads()), Approved: at, Since: at,
+			WaitsFor: "feat/y.0123456789ab", WaitsSince: at.Add(-time.Minute), Step: "the check ask of novox/mesh-sdk#40"},
+		{Group: "fix/1.2", Heads: "0123456789ac", Approved: at.Add(time.Minute), Since: at.Add(time.Minute)},
+	}}
+}
+
 func sampleAsk() Ask {
 	key, _ := MergeAskKey("feat/x", gateHeads())
 	return Ask{Group: "feat/x", Heads: gateHeads(), Ask: asks.Ask{
@@ -181,7 +190,24 @@ func TestGateValuesRoundTrip(t *testing.T) { // 1201/AC4
 			t.Errorf("owed %s round trip: %+v %v", o.Act, got, err)
 		}
 	}
+	tu := sampleTurn()
+	data, err = EncodeTurn(tu)
+	hasV("turn", data, err)
+	tu.V = Version
+	if got, err := DecodeTurn(data); err != nil || !SameTurn(got, tu) {
+		t.Errorf("turn round trip: %+v %v", got, err)
+	}
+	for _, field := range []string{`"waits-for":"feat/y.0123456789ab"`, `"waits-since":`, `"approved":`, `"step":`} {
+		if !strings.Contains(string(data), field) {
+			t.Errorf("the turn lacks %s: %s", field, data)
+		}
+	}
+	// ADR 0548 §3: a turn holds off every check but those of the heads that wait in it, whoever else waits there.
+	if !TurnHolds(tu, "fedcba987654") || TurnHolds(tu, tu.Waiting[0].Heads) || TurnHolds(tu, tu.Waiting[1].Heads) || TurnHolds(Turn{}, "fedcba987654") {
+		t.Error("TurnHolds: a turn holds other heads' checks and never the check of heads waiting in it")
+	}
 	for name, dec := range map[string]func([]byte) error{
+		"turn":   func(b []byte) error { _, err := DecodeTurn(b); return err },
 		"merge":  func(b []byte) error { _, err := DecodeMerge(b); return err },
 		"ask":    func(b []byte) error { _, err := DecodeAsk(b); return err },
 		"answer": func(b []byte) error { _, err := DecodeAnswer(b); return err },
@@ -265,6 +291,27 @@ func TestGateValuesRefused(t *testing.T) { // 1201/AC5
 	}
 	_, err = EncodeOwed(Owed{Act: OwedNote, Text: "line"})
 	wantErr("note without ref", err, "ref")
+
+	for name, c := range map[string]struct {
+		edit  func(*Turn)
+		words []string
+	}{
+		"no delivery":                {func(t *Turn) { t.Waiting = nil }, []string{"no delivery", "deleted"}},
+		"a repository in capitals":   {func(t *Turn) { t.Repository = "novox/Mesh-SDK" }, []string{"lowercase"}},
+		"no repository":              {func(t *Turn) { t.Repository = "" }, []string{"repository"}},
+		"no group":                   {func(t *Turn) { t.Waiting[0].Group = "" }, []string{"group"}},
+		"a bad heads hash":           {func(t *Turn) { t.Waiting[0].Heads = "xyz" }, []string{"xyz"}},
+		"the same heads twice":       {func(t *Turn) { t.Waiting[1].Heads = t.Waiting[0].Heads }, []string{"twice"}},
+		"no Approve time":            {func(t *Turn) { t.Waiting[1].Approved = time.Time{} }, []string{"Approve"}},
+		"out of the Approve's order": {func(t *Turn) { t.Waiting[1].Approved = t.Waiting[0].Approved.Add(-time.Hour) }, []string{"order"}},
+		"waits for no verdict key":   {func(t *Turn) { t.Waiting[0].WaitsFor = "feat/y" }, []string{"verdict key"}},
+		"a step and no check":        {func(t *Turn) { t.Waiting[1].Step = "x" }, []string{"names no check"}},
+	} {
+		tu := sampleTurn()
+		c.edit(&tu)
+		_, err = EncodeTurn(tu)
+		wantErr("turn with "+name, err, c.words...)
+	}
 	_, err = EncodeOwed(Owed{Act: OwedStatus, State: "success"})
 	wantErr("status without context", err, "context")
 }
@@ -297,7 +344,8 @@ func TestGateSame(t *testing.T) { // 1201/AC6
 func TestGateBuckets(t *testing.T) {
 	if MergesBucket != "mesh-delivery-gate_merges" || AsksBucket != "mesh-delivery-gate_asks" ||
 		OwedBucket != "mesh-delivery-gate_owed" || AnswersBucket != "mesh-delivery-teller_answers" ||
-		MergesHistory != 10 || AsksHistory != 5 || OwedHistory != 5 || AnswersHistory != 5 {
+		MergesHistory != 10 || AsksHistory != 5 || OwedHistory != 5 || AnswersHistory != 5 ||
+		TurnsBucket != "mesh-delivery-gate_turns" || TurnsHistory != 5 {
 		t.Error("a bucket or history differs from the decided layout")
 	}
 }
@@ -370,6 +418,21 @@ func TestKeysEscapeAndRoundTrip(t *testing.T) { // 1323/AC1
 		if r, n, h, a, err := ParseOwedKey(ok); err != nil || r != repo || n != 3 || h != "aaaa" || a != "view" {
 			t.Errorf("owed round trip %q = %q %d %q %q %v", repo, r, n, h, a, err)
 		}
+		// ADR 0548 §3: a repository's turn key is <owner>.<name>, lowercase, each part escaped.
+		tk, err := TurnsKey(repo)
+		if err != nil || strings.Count(tk, ".") != 1 {
+			t.Errorf("turns key for repository %q = %q, %v", repo, tk, err)
+		} else if r, err := ParseTurnsKey(tk); err != nil || r != strings.ToLower(repo) {
+			t.Errorf("turns round trip %q = %q, %v", repo, r, err)
+		}
+	}
+	if k, err := TurnsKey("novox/Mesh-SDK"); err != nil || k != "novox.mesh-sdk" {
+		t.Errorf("turns key = %q, %v; want novox.mesh-sdk", k, err)
+	}
+	for _, bad := range []string{"", "novox", "novox.", ".x", "a.b.c", "Novox.mesh-sdk", "novox.a=zz"} {
+		if _, err := ParseTurnsKey(bad); err == nil {
+			t.Errorf("parse turns key %q accepted", bad)
+		}
 	}
 	if EscapeName("a.b") != "a=2eb" || EscapeName("a=b") != "a=3db" || EscapeName("a+b") != "a=2bb" {
 		t.Errorf("escapes: %q %q %q", EscapeName("a.b"), EscapeName("a=b"), EscapeName("a+b"))

go/delivery/handed.go

@@ -0,0 +1,125 @@
+package delivery
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/seal"
+)
+
+// The adoption handing of novox/hq ADR 0547 clause 9 (issue 1945): the vault adopts, once and before `take-over`, the
+// bcrypt hashes of the bus accounts it holds no value for (the controller's own, the node accounts, the enrolled
+// devices) from the list the bus has loaded. The node-engine of the node holding mesh-broker is the one part that has
+// that list, so it hands the hashes in the bus module's have, beside what it says of the list it wrote: sealed to the
+// vault's own key, which it learns from the vault's answer to `node-key`, so that of every reader of the have bucket
+// the vault alone can open them. The have says in the clear only how many users it hands, from which list and to which
+// key; the users' names stay sealed, as the list itself is (ADR 0547 clause 7: it names every account).
+//
+// It hands every user of the loaded list; the vault takes from it only the users it holds no value for, and never
+// replaces a hash it made from a value it holds, so the node-engine never needs to read the vault's state (which the
+// grants part alone is to read, clause 9).
+
+// AccountsHanded is the hashes of the loaded list's users, sealed to the vault, in UserListWritten.
+type AccountsHanded struct {
+	// From is the digest of the list on the machine the hashes are taken from, `sha256:<hex>` (UserListWritten.Digest).
+	From string `json:"from"`
+	// To is the fingerprint of the vault's key the box is sealed to (KeyFingerprint).
+	To string `json:"to"`
+	// Users is how many users the box holds.
+	Users int `json:"users"`
+	// Box is the JSON of []HandedAccount, sealed to the vault's key (ADR 0206).
+	Box seal.Box  `json:"box"`
+	At  time.Time `json:"at"`
+}
+
+// HandedAccount is one user of an AccountsHanded box, opened: the bus user and the bcrypt hash the loaded list
+// carries for it.
+type HandedAccount struct {
+	User string `json:"user"`
+	Hash string `json:"hash"`
+}
+
+// KeyFingerprint is a public key's fingerprint as a handing names it: `sha256:<hex>` of its PEM, without the space
+// around it.
+func KeyFingerprint(publicPEM string) string {
+	sum := sha256.Sum256([]byte(strings.TrimSpace(publicPEM)))
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// listedAccount is one user of a bus user list as the composer writes it (buscompose), with its password's hash.
+var listedAccount = regexp.MustCompile(`\{\s*user:\s*"([^"]+)",\s*password:\s*"([^"]+)"`)
+
+// HandedAccountsOf is every user of a bus user list that carries a bcrypt hash, in the list's order. A user listed
+// twice is handed once, as the list first names it.
+func HandedAccountsOf(list []byte) []HandedAccount {
+	var out []HandedAccount
+	seen := map[string]bool{}
+	for _, m := range listedAccount.FindAllSubmatch(list, -1) {
+		user, hash := string(m[1]), string(m[2])
+		if seen[user] || !IsBcrypt(hash) {
+			continue
+		}
+		seen[user] = true
+		out = append(out, HandedAccount{User: user, Hash: hash})
+	}
+	return out
+}
+
+// bcryptHash is the form of a bcrypt hash: version, cost, and 53 characters of salt and digest.
+var bcryptHash = regexp.MustCompile(`^\$2[abxy]?\$[0-9]{2}\$[./A-Za-z0-9]{53}$`)
+
+// IsBcrypt says whether s has the form of a bcrypt hash.
+func IsBcrypt(s string) bool { return bcryptHash.MatchString(s) }
+
+// HandAccounts seals the accounts to the vault's public key (SPKI PEM) as the handing of the list whose digest is from.
+func HandAccounts(accounts []HandedAccount, vaultPEM, from string, at time.Time) (AccountsHanded, error) {
+	if strings.TrimSpace(vaultPEM) == "" {
+		return AccountsHanded{}, errors.New("delivery: no vault key to seal the handed accounts to")
+	}
+	body, err := json.Marshal(accounts)
+	if err != nil {
+		return AccountsHanded{}, err
+	}
+	box, err := seal.Seal(string(body), vaultPEM)
+	if err != nil {
+		return AccountsHanded{}, fmt.Errorf("delivery: the handed accounts could not be sealed to the vault's key: %w", err)
+	}
+	return AccountsHanded{From: from, To: KeyFingerprint(vaultPEM), Users: len(accounts), Box: box, At: at.UTC()}, nil
+}
+
+// OpenHanded opens a handing with the vault's private key (PEM), refusing one sealed to another key than publicPEM's
+// and a box that does not hold as many users as it says.
+func OpenHanded(h AccountsHanded, publicPEM, privatePEM string) ([]HandedAccount, error) {
+	if h.To != KeyFingerprint(publicPEM) {
+		return nil, fmt.Errorf("delivery: the handing is sealed to the key %s, not to this one (%s)", h.To,
+			KeyFingerprint(publicPEM))
+	}
+	plain, err := seal.Open(h.Box, privatePEM)
+	if err != nil {
+		return nil, fmt.Errorf("delivery: the handing does not open: %w", err)
+	}
+	var out []HandedAccount
+	if err := json.Unmarshal([]byte(plain), &out); err != nil {
+		return nil, fmt.Errorf("delivery: the handing holds no accounts: %w", err)
+	}
+	if len(out) != h.Users {
+		return nil, fmt.Errorf("delivery: the handing says %d users and holds %d", h.Users, len(out))
+	}
+	return out, nil
+}
+
+// sameHanded says whether two handings say the same: the same list, key, count and box, whatever zone their time is in.
+func sameHanded(a, b *AccountsHanded) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	x, y := *a, *b
+	x.At, y.At = time.Time{}, time.Time{}
+	return x == y && a.At.Equal(b.At)
+}

go/delivery/stepasks.go

@@ -45,6 +45,86 @@ const (
 // AskLanguages are the build seats' languages.
 var AskLanguages = []string{AskGo, AskNode, AskImage}
 
+// **An ask may name what its node needs** (issue 890, novox/hq ADR 0525 §1 as the placement record amends it). The seat's
+// workers are shared, so the asker still chooses no node; a check ask whose packages' tests need something only some
+// nodes have names it in Needs, and a holder whose node lacks one of them takes no part of the ask: it ends the ask's step
+// refused as declined (StepDeclined) and drops the message, and the asker puts the ask again under a new id, so a node
+// that has the need takes it. A need is a node seat whose holder installs what the tests read on its node; a package
+// declares it beside its tests, and the build module's digest reports it (LevelDigest.Needs).
+
+// NeedNodeBuildNode is the need of a package whose integration tests read the Node build module's installed toolchain
+// (ADR 0533 §1): the node holds the seat node-build-node, so its toolchain is installed where the Go build module's
+// integration level is given it.
+const NeedNodeBuildNode = "node-build-node"
+
+// AskNeeds are the needs an ask may name.
+var AskNeeds = []string{NeedNodeBuildNode}
+
+// CheckNeed refuses a need that is not one of AskNeeds.
+func CheckNeed(need string) error {
+	for _, n := range AskNeeds {
+		if need == n {
+			return nil
+		}
+	}
+	return fmt.Errorf("delivery: %q is not a need an ask may name (%s)", need, strings.Join(AskNeeds, ", "))
+}
+
+// Lacks is what of needs has does not say the node has, in the order of needs; a nil has has nothing.
+func Lacks(needs []string, has func(need string) bool) []string {
+	var out []string
+	for _, n := range needs {
+		if has == nil || !has(n) {
+			out = append(out, n)
+		}
+	}
+	return out
+}
+
+// PackageNeeds is one package and what its tests need of the node at a level.
+type PackageNeeds struct {
+	Package string   `json:"package"`
+	Needs   []string `json:"needs"`
+}
+
+// StepDeclined is the result of the step of an ask a holder declined: the ask's needs, and those the holder's node lacks.
+// The step's state is refused; the asker puts the ask again under a new id (DeclinedOf).
+type StepDeclined struct {
+	Declined bool     `json:"declined"`
+	Needs    []string `json:"needs"`
+	Lacks    []string `json:"lacks"`
+}
+
+// DeclinedOf says whether step is a declined ask's, and what its node lacked.
+func DeclinedOf(step Step) (StepDeclined, bool) {
+	if step.State != StepRefused || len(step.Result) == 0 {
+		return StepDeclined{}, false
+	}
+	var d StepDeclined
+	if err := json.Unmarshal(step.Result, &d); err != nil || !d.Declined {
+		return StepDeclined{}, false
+	}
+	return d, true
+}
+
+// UnmetNeeds are the needs of the packages the levels left untested (LevelAnswer.Unmet), each once, sorted.
+func UnmetNeeds(levels []LevelAnswer) []string {
+	seen := map[string]bool{}
+	var out []string
+	for _, l := range levels {
+		for _, u := range l.Unmet {
+			for _, n := range u.Needs {
+				if !seen[n] {
+					seen[n] = true
+					out = append(out, n)
+				}
+			}
+		}
+	}
+	sort.Strings(out)
+	return out
+}
+
 // AskRuns is how many times an ask is run before it is taken for poison (issue 1907): an ask whose run never ends (it
 // takes its node down, or its process dies with it) is delivered again by its stream to the next free node (ADR 0525
 // §6); the holder that takes it past AskRuns runs it no more, writes its step failed saying so, and ends it, so the
@@ -171,6 +251,8 @@ type StepAsk struct {
 	Build   *BuildJob   `json:"build,omitempty"`
 	Check   *CheckJob   `json:"check,omitempty"`
 	Compose *ComposeJob `json:"compose,omitempty"`
+	// Needs are what the node that runs the ask must have (AskNeeds); a check ask's alone. Empty: any node.
+	Needs []string `json:"needs,omitempty"`
 }
 
 // ComposeJob is a compose ask's job (novox/hq ADR 0482 clause 4, issue 1622): fetch the commit, build the composer
@@ -255,6 +337,9 @@ type CheckJob struct {
 	RunnerWhen string `json:"runner_when,omitempty"`
 	// Run is a try's test pattern (go test -run): each level runs it alone, digesting nothing.
 	Run string `json:"run,omitempty"`
+	// Packages, when set, are the only packages each level tests (issue 890, ADR 0552 §4): a placed ask names the
+	// packages the first ask left unmet, and the others are neither tested nor taken kept, so nothing is judged twice.
+	Packages []string `json:"packages,omitempty"`
 }
 
 func (a StepAsk) check() error {
@@ -290,6 +375,13 @@ func (a StepAsk) check() error {
 		return fmt.Errorf("delivery: the ask %s is a check on the delivery stream, which carries trunk builds alone", a.ID)
 	case a.Check != nil && a.Language == AskImage:
 		return fmt.Errorf("delivery: the ask %s is a check of an image, which has no tests", a.ID)
+	case len(a.Needs) > 0 && a.Check == nil:
+		return fmt.Errorf("delivery: the ask %s names needs and is no check, whose tests alone need a node", a.ID)
+	}
+	for _, n := range a.Needs {
+		if err := CheckNeed(n); err != nil {
+			return fmt.Errorf("the ask %s: %w", a.ID, err)
+		}
 	}
 	if a.Build != nil {
 		return a.Build.check(a.ID)
@@ -350,6 +442,11 @@ func (c CheckJob) check(id string) error {
 			return err
 		}
 	}
+	for _, p := range c.Packages {
+		if p == "" || strings.ContainsAny(p, " \t\n") {
+			return fmt.Errorf("delivery: the check ask %s names a package %q that is no import path", id, p)
+		}
+	}
 	return checkFetchArgs(id, c.Fetch)
 }
 
@@ -433,6 +530,9 @@ type LevelAnswer struct {
 	Digest *LevelDigest      `json:"digest,omitempty"`
 	Kept   []KeptTaken       `json:"kept,omitempty"`
 	Tests  []json.RawMessage `json:"tests,omitempty"`
+	// Unmet are the packages the level did not test on this node, because their tests need what it lacks (issue 890): the
+	// asker keeps what passed and asks them again of a node that has it (StepAsk.Needs).
+	Unmet []PackageNeeds `json:"unmet,omitempty"`
 }
 
 // LevelDigest is the digest's answer as a level keeps it in the ask's step result: its packages a list of
@@ -446,6 +546,8 @@ type LevelDigest struct {
 	Beside       []string        `json:"beside,omitempty"`
 	WithoutTests []string        `json:"without_tests,omitempty"`
 	JudgedBy     string          `json:"judged_by,omitempty"`
+	// Needs are the packages whose tests at this level need something of the node (issue 890), as they declare it.
+	Needs []PackageNeeds `json:"needs,omitempty"`
 }
 
 // PackageDigest is one package's digest at a level.
@@ -463,6 +565,7 @@ func (d *LevelDigest) UnmarshalJSON(raw []byte) error {
 		Beside       []string        `json:"beside"`
 		WithoutTests []string        `json:"without_tests"`
 		JudgedBy     string          `json:"judged_by"`
+		Needs        []PackageNeeds  `json:"needs"`
 	}
 	if err := json.Unmarshal(raw, &v); err != nil {
 		return err
@@ -482,7 +585,20 @@ func (d *LevelDigest) UnmarshalJSON(raw []byte) error {
 		}
 	}
 	sort.Slice(pkgs, func(i, j int) bool { return pkgs[i].Package < pkgs[j].Package })
-	*d = LevelDigest{Level: v.Level, Packages: pkgs, Beside: v.Beside, WithoutTests: v.WithoutTests, JudgedBy: v.JudgedBy}
+	*d = LevelDigest{Level: v.Level, Packages: pkgs, Beside: v.Beside, WithoutTests: v.WithoutTests, JudgedBy: v.JudgedBy, Needs: v.Needs}
+	return nil
+}
+
+// NeedsOf is what the package's tests need of the node at the digest's level; nil when it declares nothing.
+func (d *LevelDigest) NeedsOf(pkg string) []string {
+	if d == nil {
+		return nil
+	}
+	for _, n := range d.Needs {
+		if n.Package == pkg {
+			return n.Needs
+		}
+	}
 	return nil
 }
 
@@ -535,6 +651,11 @@ func ParseAskStepKey(key string) (node, askID string, err error) {
 	return node, askID, nil
 }
 
+// StepBound is how long an asker waits for one ask's step once a build node took it (30 minutes): past it the asker has
+// stopped waiting, so a key still running is nobody's. The build modules end such a key (buildstep.EndStale); the
+// checker's, the builder's and the watchman's own copies of the number are to read this one (issue 1916).
+const StepBound = 30 * time.Minute
+
 // PausesState is the state a build module keeps its nodes' pause keys in. It has no age, unlike StepsState, whose keys
 // are per step and dropped after their age: a pause kept among the steps would end by itself.
 const PausesState = "pauses"

go/delivery/stepasks_test.go

@@ -56,6 +56,7 @@ func TestAskRefusesUnknownKindAndLanguage(t *testing.T) {
 		"recheck":  func(a *StepAsk) { a.Kind = AskRecheck },
 		"commit":   func(a *StepAsk) { a.Build.Fetch = map[string]any{"repository": "novox/x", "commit": "main"} },
 		"path":     func(a *StepAsk) { a.Build.Path = "" },
+		"needs":    func(a *StepAsk) { a.Needs = []string{NeedNodeBuildNode} }, // issue 890: a build needs no node
 	}
 	for name, change := range cases {
 		a := buildAsk()
@@ -80,6 +81,23 @@ func TestAskRefusesUnknownKindAndLanguage(t *testing.T) {
 	if _, err := EncodeStepAsk(c); err == nil {
 		t.Error("a check of an image encoded")
 	}
+	// Issue 890: a check names a known need and round-trips it; an unknown need is refused.
+	c = checkAsk()
+	c.Check.Packages = []string{"a b"}
+	if _, err := EncodeStepAsk(c); err == nil {
+		t.Error("a package that is no import path encoded")
+	}
+	c.Check.Packages = []string{"x/pkg/a"}
+	c.Needs = []string{"gpu"}
+	if _, err := EncodeStepAsk(c); err == nil {
+		t.Error("an unknown need encoded")
+	}
+	c.Needs = []string{NeedNodeBuildNode}
+	if raw, err := EncodeStepAsk(c); err != nil {
+		t.Errorf("a check needing %s: %v", NeedNodeBuildNode, err)
+	} else if back, err := DecodeStepAsk(raw); err != nil || len(back.Needs) != 1 || back.Needs[0] != NeedNodeBuildNode {
+		t.Errorf("the need did not round-trip: %+v %v", back.Needs, err)
+	}
 	raw, _ := EncodeStepAsk(buildAsk())
 	for _, bad := range []string{
 		strings.Replace(string(raw), `"kind":"delivery"`, `"kind":"queue"`, 1),

go/delivery/steps.go

@@ -70,6 +70,9 @@ type Step struct {
 	Ended   time.Time       `json:"ended,omitzero"`
 	Reason  string          `json:"reason,omitempty"`
 	Result  json.RawMessage `json:"result,omitempty"`
+	// What says what the step is, for a reader of the steps state: an ask's kind, repository, head and levels or
+	// module (issue 1890). Empty for a step a tool started by hand.
+	What string `json:"what,omitempty"`
 }
 
 func (s Step) check() error {

go/delivery/turns.go

@@ -0,0 +1,174 @@
+package delivery
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+// **The merge turns** (novox/hq ADR 0548 clauses 3 and 4). An approved merge holds a turn on each repository it goes into:
+// before it reads the checker's verdicts for the merge, the gate writes one key per repository in its bucket turns, naming
+// the deliveries that wait in the order of their Approve, the verdict key each waits for and since when. The gate is the
+// key's one writer; the checker is granted to read the bucket, reads it absent as empty, and claims no check of a repository
+// a turn names, except the check of the waiting delivery's own heads (TurnHolds). The key goes when the last delivery in it
+// merged or left.
+const (
+	// TurnsBucket is the gate's bucket of merge turns.
+	TurnsBucket = GateModule + "_turns"
+	// TurnsHistory is the revisions the turns bucket keeps per key.
+	TurnsHistory = 5
+)
+
+// TurnsKey is the key, in TurnsBucket, of a repository's turn: `<owner>.<name>`, lowercase, each part escaped (EscapeName),
+// so the key names the repository the checker's verdicts name as a trunk whatever its case.
+func TurnsKey(repository string) (string, error) {
+	repository = strings.ToLower(repository)
+	if _, err := escapeRepository(repository); err != nil {
+		return "", err
+	}
+	owner, name, _ := strings.Cut(repository, "/")
+	return EscapeName(owner) + "." + EscapeName(name), nil
+}
+
+// ParseTurnsKey is the inverse of TurnsKey: the repository, lowercase.
+func ParseTurnsKey(key string) (string, error) {
+	owner, name, ok := strings.Cut(key, ".")
+	if !ok || owner == "" || name == "" || strings.Contains(name, ".") {
+		return "", fmt.Errorf("delivery: %q is not a turns key, <owner>.<name>", key)
+	}
+	o, err := UnescapeName(owner)
+	if err != nil {
+		return "", fmt.Errorf("delivery: %q is not a turns key: %w", key, err)
+	}
+	n, err := UnescapeName(name)
+	if err != nil {
+		return "", fmt.Errorf("delivery: %q is not a turns key: %w", key, err)
+	}
+	repository := o + "/" + n
+	if again, err := TurnsKey(repository); err != nil || again != key {
+		return "", fmt.Errorf("delivery: %q is not a turns key: it does not name a lowercase <owner>/<name>", key)
+	}
+	return repository, nil
+}
+
+// Turn is the value of a turns key: the repository and the approved deliveries that wait to merge into it, in the order of
+// their Approve. A turn with no delivery is no value: its key is deleted.
+type Turn struct {
+	V          int        `json:"v"`
+	Repository string     `json:"repository"`
+	Waiting    []TurnWait `json:"waiting"`
+}
+
+// TurnWait is one approved delivery in a turn: its group (a lone pull request's branch), the hash of the heads the Approve
+// covers (the checker's verdict key's hash, HeadsHash over its members), the Approve's ask key, when it was approved and since
+// when it waits; and, while a check of another delivery runs on the repository, that check's verdict key, when the gate saw
+// it start, and the step the checker says it is at.
+type TurnWait struct {
+	Group    string    `json:"group"`
+	Heads    string    `json:"heads"`
+	Ask      string    `json:"ask,omitempty"`
+	Approved time.Time `json:"approved"`
+	Since    time.Time `json:"since"`
+	// WaitsFor is the verdict key (`<group>.<heads hash>`) of the running check the merge waits for; empty when none runs.
+	WaitsFor   string    `json:"waits-for,omitempty"`
+	WaitsSince time.Time `json:"waits-since,omitzero"`
+	Step       string    `json:"step,omitempty"`
+}
+
+func (t Turn) check() error {
+	repository := strings.ToLower(t.Repository)
+	if repository != t.Repository {
+		return fmt.Errorf("delivery: the turn's repository %q is not lowercase", t.Repository)
+	}
+	if _, err := escapeRepository(repository); err != nil {
+		return err
+	}
+	if len(t.Waiting) == 0 {
+		return fmt.Errorf("delivery: the turn of %s names no delivery: its key is deleted instead", t.Repository)
+	}
+	seen := map[string]bool{}
+	for i, w := range t.Waiting {
+		if w.Group == "" {
+			return fmt.Errorf("delivery: a delivery in the turn of %s names no group", t.Repository)
+		}
+		if !isHex12(w.Heads) {
+			return fmt.Errorf("delivery: the heads hash %q in the turn of %s is not 12 lowercase hex digits", w.Heads, t.Repository)
+		}
+		if seen[w.Heads] {
+			return fmt.Errorf("delivery: the turn of %s names the heads %s twice", t.Repository, w.Heads)
+		}
+		seen[w.Heads] = true
+		if w.Approved.IsZero() || w.Since.IsZero() {
+			return fmt.Errorf("delivery: the delivery %s in the turn of %s says no time of its Approve or of its wait", w.Group, t.Repository)
+		}
+		if i > 0 && w.Approved.Before(t.Waiting[i-1].Approved) {
+			return fmt.Errorf("delivery: the turn of %s is not in the order of the Approve: %s was approved before %s", t.Repository, w.Group, t.Waiting[i-1].Group)
+		}
+		if w.WaitsFor != "" {
+			if _, _, err := ParseCheckerVerdictKey(w.WaitsFor); err != nil {
+				return fmt.Errorf("delivery: the delivery %s in the turn of %s waits for what is not a verdict key: %w", w.Group, t.Repository, err)
+			}
+		} else if !w.WaitsSince.IsZero() || w.Step != "" {
+			return fmt.Errorf("delivery: the delivery %s in the turn of %s says when and where a check runs, and names no check", w.Group, t.Repository)
+		}
+	}
+	return nil
+}
+
+// TurnHolds says whether a turn holds off the check of the heads: it names deliveries, and none of them of these heads. A
+// turn never holds the check of heads that wait in it (the carry a waiting merge needs): two approved merges in one turn whose
+// trunk moved would otherwise each hold the other's carry, and neither would ever merge (review of ADR 0548's build, round 1).
+func TurnHolds(t Turn, heads string) bool {
+	if len(t.Waiting) == 0 {
+		return false
+	}
+	for _, w := range t.Waiting {
+		if w.Heads == heads {
+			return false
+		}
+	}
+	return true
+}
+
+// EncodeTurn is t as JSON at Version; it refuses a turn with no delivery, a repository that is not lowercase <owner>/<name>,
+// a delivery without its group, heads hash or times, the same heads twice, an order other than the Approve's, and a check
+// waited for that is not a verdict key.
+func EncodeTurn(t Turn) ([]byte, error) {
+	if err := t.check(); err != nil {
+		return nil, err
+	}
+	t.V = Version
+	return json.Marshal(t)
+}
+
+// DecodeTurn reads a turn; it refuses an unknown version (ErrUnknownVersion) and what EncodeTurn refuses.
+func DecodeTurn(data []byte) (Turn, error) {
+	var t Turn
+	if err := decode(data, &t); err != nil {
+		return Turn{}, err
+	}
+	if err := t.check(); err != nil {
+		return Turn{}, err
+	}
+	return t, nil
+}
+
+// SameTurn says whether two turns are the same value, so the gate writes only when they differ.
+func SameTurn(a, b Turn) bool {
+	if len(a.Waiting) != len(b.Waiting) || a.Repository != b.Repository || a.V != b.V {
+		return false
+	}
+	for i := range a.Waiting {
+		x, y := a.Waiting[i], b.Waiting[i]
+		if !x.Approved.Equal(y.Approved) || !x.Since.Equal(y.Since) || !x.WaitsSince.Equal(y.WaitsSince) {
+			return false
+		}
+		x.Approved, y.Approved, x.Since, y.Since, x.WaitsSince, y.WaitsSince = time.Time{}, time.Time{}, time.Time{}, time.Time{}, time.Time{}, time.Time{}
+		if !reflect.DeepEqual(x, y) {
+			return false
+		}
+	}
+	return true
+}

go/delivery/userlist.go

@@ -0,0 +1,149 @@
+package delivery
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/seal"
+)
+
+// **The grants part's user list, sealed to the bus node** (novox/hq ADR 0547 clauses 7 and 8, issue 1945): the contract
+// between the grants part (mesh-delivery modules/mesh-grants), which writes it, and the node-engine of the node holding
+// mesh-broker (mesh-host), which follows it once the operator's take-over says so.
+//
+//   - The grants part composes the bus's user list (the accounts block, buscompose.ComposeAccounts, with the vault's
+//     hashes), seals it to the bus node's sealing key (seal.Seal, the key the node says in its have of the bus module,
+//     UserListWritten.Key), and puts the box as one object of its object bucket GrantsUserListObjects, named by the
+//     list's digest (UserListObjectName).
+//   - It writes the key GrantsUserListKey of its state `user-list` (bucket GrantsUserListBucket): the GrantsUserList
+//     below, which names the object, the list's digest, its revision, its user count and the users left out, and which
+//     source the bus node follows (Follow: FollowGrants from take-over, FollowController in shadow and after hand-back).
+//   - The node-engine of the bus node watches that key alone. While it says FollowGrants it opens the object, checks
+//     the digest, writes the bus's user-list file (mode 0600) only when the file's digest differs, and says what it
+//     loaded in its have of the bus module (UserListWritten, Source GrantsUserListSource); otherwise it follows the
+//     controller's compositions as before (clause 8). Never both.
+
+// The names of the grants part's user list on the bus.
+const (
+	// GrantsUserListBucket is the grants part's state `user-list`.
+	GrantsUserListBucket = "mesh-grants_user-list"
+	// GrantsUserListKey is the one key of it the bus node reads.
+	GrantsUserListKey = "sealed"
+	// GrantsUserListObjects is the grants part's object bucket, where each sealed list is one object.
+	GrantsUserListObjects = "mesh-grants-user-list"
+	// GrantsUserListObjectStream is the bucket's stream.
+	GrantsUserListObjectStream = "OBJ_" + GrantsUserListObjects
+	// GrantsUserListSource is the source a have names for a list taken from the grants part.
+	GrantsUserListSource = GrantsUserListBucket + "." + GrantsUserListKey
+)
+
+// Which list the bus node follows.
+const (
+	FollowController = "controller"
+	FollowGrants     = "grants"
+)
+
+// GrantsUserList is the value of the grants part's key `user-list.sealed`.
+type GrantsUserList struct {
+	V int `json:"v"`
+	// Follow is which list the bus node follows: FollowGrants from take-over, FollowController otherwise.
+	Follow string `json:"follow"`
+	// Digest is the list's digest, `sha256:<hex>` of the file's bytes as the bus loads them.
+	Digest string `json:"digest"`
+	// Object is the object's name in GrantsUserListObjects (UserListObjectName of Digest).
+	Object string `json:"object"`
+	// SealedTo is the fingerprint of the key the object is sealed to (SealingKeyID), and Node the node it holds.
+	SealedTo string `json:"sealed_to"`
+	Node     string `json:"node"`
+	// Revision counts the lists the grants part wrote: one more for each new digest.
+	Revision uint64 `json:"revision"`
+	Users    int    `json:"users"`
+	// LeftOut are the users the list leaves out for want of a hash in the vault.
+	LeftOut []string  `json:"left_out"`
+	At      time.Time `json:"at"`
+}
+
+// EncodeGrantsUserList is g as JSON at Version; it refuses a value the bus node could not follow.
+func EncodeGrantsUserList(g GrantsUserList) ([]byte, error) {
+	g.V = Version
+	if g.LeftOut == nil {
+		g.LeftOut = []string{}
+	}
+	if err := g.check(); err != nil {
+		return nil, err
+	}
+	return json.Marshal(g)
+}
+
+// DecodeGrantsUserList reads the key's value; it refuses another version and what Encode refuses.
+func DecodeGrantsUserList(data []byte) (GrantsUserList, error) {
+	var g GrantsUserList
+	if err := decode(data, &g); err != nil {
+		return GrantsUserList{}, err
+	}
+	if err := g.check(); err != nil {
+		return GrantsUserList{}, err
+	}
+	return g, nil
+}
+
+func (g GrantsUserList) check() error {
+	if g.Follow != FollowGrants && g.Follow != FollowController {
+		return fmt.Errorf("delivery: the user list's follow %q is not %s or %s", g.Follow, FollowGrants, FollowController)
+	}
+	if g.Digest == "" {
+		return nil // a switch with no list written yet: the bus node keeps what it follows
+	}
+	if !strings.HasPrefix(g.Digest, "sha256:") || g.Object != UserListObjectName(g.Digest) {
+		return fmt.Errorf("delivery: the user list names object %q for digest %q; the object is the digest's hex", g.Object, g.Digest)
+	}
+	return nil
+}
+
+// UserListDigest is a list's digest as the have and the key say it, `sha256:<hex>` of its bytes.
+func UserListDigest(content []byte) string {
+	sum := sha256.Sum256(content)
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// UserListObjectName is the object a list of that digest is put under: the digest's hex.
+func UserListObjectName(digest string) string { return strings.TrimPrefix(digest, "sha256:") }
+
+// SealingKeyID is a short fingerprint of a public key in PEM, `sha256:<16 hex>`, to say which key a box is sealed to
+// without carrying the key.
+func SealingKeyID(publicPEM string) string {
+	sum := sha256.Sum256([]byte(strings.TrimSpace(publicPEM)))
+	return "sha256:" + hex.EncodeToString(sum[:8])
+}
+
+// SealUserList is the object a list is put as: the sealed box (seal.Seal) of its bytes to the bus node's key, as JSON.
+func SealUserList(list []byte, nodePEM string) ([]byte, error) {
+	if !strings.Contains(nodePEM, "PUBLIC KEY") {
+		return nil, fmt.Errorf("delivery: the bus node's key is not a public key in PEM")
+	}
+	box, err := seal.Seal(string(list), nodePEM)
+	if err != nil {
+		return nil, fmt.Errorf("delivery: the user list could not be sealed: %w", err)
+	}
+	return json.Marshal(box)
+}
+
+// OpenUserList opens an object with open (the node's own key) and checks it is the list of digest.
+func OpenUserList(object []byte, digest string, open func(seal.Box) ([]byte, error)) ([]byte, error) {
+	var box seal.Box
+	if err := json.Unmarshal(object, &box); err != nil {
+		return nil, fmt.Errorf("delivery: the object is no sealed box: %w", err)
+	}
+	list, err := open(box)
+	if err != nil {
+		return nil, err
+	}
+	if got := UserListDigest(list); got != digest {
+		return nil, fmt.Errorf("delivery: the opened list's digest is %s, and the key names %s", got, digest)
+	}
+	return list, nil
+}

go/forgekey/keykeeper.go

@@ -101,7 +101,7 @@ func (k *KeyKeeper) ensure(ctx context.Context) error {
 	}
 	r := k.Run(ctx, nil, "ssh-keygen", "-q", "-t", "ed25519", "-N", "", "-C", k.Account+"@"+k.Node+" (mesh)", "-f", k.path())
 	if r.Status != 0 || r.Err != "" {
-		return fmt.Errorf("ssh-keygen: %s", firstLine(r.Err+" "+r.Stderr))
+		return fmt.Errorf("ssh-keygen: %s", Said(r.Err+"\n"+r.Stderr))
 	}
 	return nil
 }

go/forgekey/runner.go

@@ -9,6 +9,7 @@ import (
 	"os/exec"
 	"strings"
 	"time"
+	"unicode/utf8"
 )
 
 // Ran is what a command did: its output, its exit status, and why it never ran to an answer.
@@ -43,7 +44,8 @@ func ExecRunnerFor(bound time.Duration) Runner {
 
 // ExecRunnerClean is ExecRunnerFor whose commands get exactly the env argument as their environment, and nothing of
 // this process's (issue 1497; novox/hq ADR 0466 §4: no registry password in a fetch's environment). The caller
-// gives PATH and HOME itself. A directory is the command's own business (`git -C`, `go -C`).
+// gives PATH and HOME itself. A directory is the command's own business (`git -C`, `go -C`): it is started in the HOME
+// it is given, or the machine's temporary directory, never in this process's (stableDir).
 func ExecRunnerClean(bound time.Duration) Runner {
 	return func(ctx context.Context, env []string, name string, args ...string) Ran {
 		return execRun(ctx, bound, true, env, name, args...)
@@ -62,6 +64,7 @@ func execRun(ctx context.Context, bound time.Duration, clean bool, env []string,
 	} else {
 		cmd.Env = append(os.Environ(), env...)
 	}
+	cmd.Dir = stableDir(clean, env)
 	var out, errb bytes.Buffer
 	cmd.Stdout, cmd.Stderr = &out, &errb
 	err := cmd.Run()
@@ -83,11 +86,60 @@ func execRun(ctx context.Context, bound time.Duration, clean bool, env []string,
 	return r
 }
 
-func firstLine(s string) string {
-	for _, l := range strings.Split(s, "\n") {
-		if l = strings.TrimSpace(l); l != "" {
-			return l
+// stableDir is the directory a command starts in when it names none (novox/hq issue 734). **Never one that may be
+// deleted under it**: a module runs in the directory its build was unpacked in, which a new build replaces, and a
+// command started there inherits it — `go version` then fails "getwd: no such file or directory" before it reads
+// anything. A clean command starts in the HOME it is given, or the temporary directory; any other keeps this
+// process's directory while it exists, and starts in the temporary directory once it is gone. "" is this process's.
+func stableDir(clean bool, env []string) string {
+	if !clean {
+		if _, err := os.Getwd(); err == nil {
+			return ""
+		}
+		return os.TempDir()
+	}
+	for i := len(env) - 1; i >= 0; i-- {
+		if home, ok := strings.CutPrefix(env[i], "HOME="); ok {
+			if info, err := os.Stat(home); err == nil && info.IsDir() {
+				return home
+			}
+			break
 		}
 	}
-	return ""
+	return os.TempDir()
+}
+
+// SaidBound bounds what Said keeps of a command's words, so a reason stays a line of a step's record and of a log.
+const SaidBound = 600
+
+// Said is what a command said of its failure in its own words, for a reason: every line that says something, trimmed
+// and joined with "; ", bounded at SaidBound bytes. A line that is a bare prefix and nothing else (git writes "error:"
+// alone before and after the forge's own message, "remote:" or "fatal:" likewise) is left out, so the cause is never
+// cut off behind it: the first line alone of `git fetch` from a repository the account cannot read was "error:".
+func Said(s string) string {
+	var keep []string
+	for _, l := range strings.Split(s, "\n") {
+		l = strings.TrimSpace(l)
+		if l == "" || barePrefix(l) {
+			continue
+		}
+		keep = append(keep, l)
+	}
+	out := strings.Join(keep, "; ")
+	if len(out) > SaidBound {
+		cut := SaidBound
+		for cut > 0 && !utf8.RuneStart(out[cut]) {
+			cut--
+		}
+		out = out[:cut] + " …"
+	}
+	return out
+}
+
+// barePrefix says whether a line is one word and a colon, such as "error:" or "remote:", with nothing after it.
+func barePrefix(l string) bool {
+	if !strings.HasSuffix(l, ":") {
+		return false
+	}
+	return !strings.ContainsAny(strings.TrimSuffix(l, ":"), " \t:")
 }

go/forgekey/runner_test.go

@@ -48,13 +48,29 @@ func TestExecRunnerForZeroIsCutByItsContext(t *testing.T) {
 	}
 }
 
-// 1497/AC4: ExecRunnerClean(0) runs env with only the given words: PATH and HOME, not the process's secret.
+// 1497/AC4: ExecRunnerClean(0) runs env with only the given words: PATH and HOME, not the process's secret. And issue
+// 734: run from a process whose own directory was deleted under it (a module whose build a new one replaced), a clean
+// command starts in its HOME, and any other in the temporary directory, rather than failing to find where it is.
 func TestExecRunnerCleanGivesTheCommandOnlyTheEnvArgument(t *testing.T) {
 	t.Setenv("MESH_TEST_SECRET", "x")
 	r := ExecRunnerClean(0)(context.Background(), []string{"PATH=" + os.Getenv("PATH"), "HOME=/h"}, "env")
 	if r.Status != 0 || !strings.Contains(r.Stdout, "HOME=/h") || !strings.Contains(r.Stdout, "PATH=") || strings.Contains(r.Stdout, "MESH_TEST_SECRET") {
 		t.Errorf("ran = %+v", r)
 	}
+
+	home, gone := t.TempDir(), t.TempDir()
+	t.Chdir(gone)
+	if err := os.Remove(gone); err != nil {
+		t.Fatal(err)
+	}
+	r = ExecRunnerClean(0)(context.Background(), []string{"PATH=" + os.Getenv("PATH"), "HOME=" + home}, "pwd")
+	if r.Status != 0 || strings.TrimSpace(r.Stdout) != home {
+		t.Errorf("a clean command run from a deleted directory = %+v, want it started in its HOME %s", r, home)
+	}
+	r = ExecRunnerFor(0)(context.Background(), nil, "pwd")
+	if r.Status != 0 || strings.TrimSpace(r.Stdout) != os.TempDir() {
+		t.Errorf("a command run from a deleted directory = %+v, want it started in %s", r, os.TempDir())
+	}
 }
 
 // 1497/AC5: ExecRunnerFor(0) is unchanged: the env argument is added to the process's environment.

go/forgekey/said_test.go

@@ -0,0 +1,28 @@
+package forgekey
+
+import (
+	"strings"
+	"testing"
+)
+
+// git's own words survive as the reason: a bare "error:" or "fatal:" line is never the whole reason (the mirror of
+// jschoubben/car-hunter "is not used: git -C: error:", 2026-10-26), every line that says something is kept, and the
+// words are bounded.
+func TestSaidKeepsTheCauseBehindABarePrefix(t *testing.T) {
+	forge := "error: \nerror: User: 22:nox-builder with Key: 30:mesh:ace.mesh-build-go is not authorized to read jschoubben/car-hunter.\nerror: \nfatal: Could not read from remote repository.\n\nPlease make sure you have the correct access rights\nand the repository exists.\n"
+	for _, c := range []struct{ name, in, want string }{
+		{"forge refusal", forge, "error: User: 22:nox-builder with Key: 30:mesh:ace.mesh-build-go is not authorized to read jschoubben/car-hunter.; fatal: Could not read from remote repository.; Please make sure you have the correct access rights; and the repository exists."},
+		{"one line", "fatal: couldn't find remote ref x\n", "fatal: couldn't find remote ref x"},
+		{"bare prefixes only", "error:\nremote:\n", ""},
+		{"a colon inside stays", " ENOENT \nfatal: bad: thing\n", "ENOENT; fatal: bad: thing"},
+		{"empty", "", ""},
+	} {
+		if got := Said(c.in); got != c.want {
+			t.Errorf("%s: Said = %q, want %q", c.name, got, c.want)
+		}
+	}
+	long := Said(strings.Repeat("é", SaidBound))
+	if !strings.HasSuffix(long, " …") || len(long) > SaidBound+len(" …") || !strings.HasPrefix(long, "é") {
+		t.Errorf("long: %d bytes, ends %q", len(long), long[len(long)-6:])
+	}
+}

go/process/account_test.go

@@ -1,11 +1,19 @@
 package process
 
 import (
+	"context"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
 )
 
 // 1171/AC2: given an account file broker-<process id> in the controller's form {url, fingerprint, node,
@@ -46,6 +54,97 @@ func TestReadAccountToleratesNoClaimsAtAll(t *testing.T) {
 // 1171/AC2: a file missing url, user or password is refused, naming the field; the password never appears
 // in the error even when it is the field present and another is missing.
 func TestReadAccountRefusesAFileMissingAField(t *testing.T) {
+	t.Run("1945: a refused bucket stops a start only when the part cannot work without it", func(t *testing.T) {
+		refusal := errors.New("nats: permissions violation for publish to $JS.API.STREAM.INFO.KV_mesh-delivery-gate_source")
+		for _, c := range []struct {
+			name string
+			err  error
+		}{{"refused", refusal}, {"not answered", context.DeadlineExceeded}} {
+			var said []string
+			logf := func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }
+			if kv := OptionalBucket(context.Background(), refusingBus{c.err}, "b", "b is not heard", logf); kv != nil {
+				t.Errorf("%s: an optional bucket answered %v", c.name, kv)
+			}
+			NotWatched(logf, "b", c.err, "b is not heard")
+			if len(said) != 2 || !strings.Contains(said[0], c.err.Error()) || !strings.Contains(said[1], "cannot be watched") {
+				t.Errorf("%s: said %q", c.name, said)
+			}
+			if _, err := EssentialBucket(context.Background(), refusingBus{c.err}, "builder", "b", "build"); err == nil ||
+				!strings.Contains(err.Error(), "grant of b") || !strings.Contains(err.Error(), "the builder cannot build") {
+				t.Errorf("%s: an essential bucket: %v", c.name, err)
+			}
+		}
+	})
+
+	t.Run("1790: a bucket missing at start is bound when the bus says it was created, and what was written meanwhile is kept", func(t *testing.T) {
+		bus := &laterBus{}
+		hear := &heldSubscriber{}
+		var said []string
+		logf := func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }
+		b := AwaitBucket(context.Background(), bus, hear, "m_hearing", "the health tool cannot say it", logf)
+		if hear.subject != "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_m_hearing" {
+			t.Fatalf("heard %q", hear.subject)
+		}
+		ready := make(chan jetstream.KeyValue, 1)
+		b.Ready(func(kv jetstream.KeyValue) { ready <- kv })
+		for _, v := range []string{"one", "two"} {
+			if _, err := b.Put(context.Background(), "dead-letters", []byte(v)); !errors.Is(err, ErrNotYet) {
+				t.Fatalf("a write while missing: %v", err)
+			}
+		}
+		if b.KV() != nil || len(ready) > 0 {
+			t.Fatal("bound before the bucket exists")
+		}
+		bus.create()
+		hear.deliver()
+		select {
+		case <-ready:
+		case <-time.After(5 * time.Second):
+			t.Fatal("not bound within 5s of the bus saying the bucket was created")
+		}
+		if got := bus.kv.puts; strings.Join(got, ",") != "dead-letters=two" {
+			t.Errorf("written when it appeared: %v, want the latest value only", got)
+		}
+		if _, err := b.Put(context.Background(), "dead-letters", []byte("three")); err != nil {
+			t.Errorf("a write once bound: %v", err)
+		}
+		if len(said) != 2 || !strings.Contains(said[0], "cannot be read yet") || !strings.Contains(said[1], "appeared") {
+			t.Errorf("said %q", said)
+		}
+		// The bus refuses the subscription to the creation: said once, loudly; a reconnect hears it again and binds.
+		refusedBus, refusing := &laterBus{}, &heldSubscriber{refused: true}
+		var loud []string
+		r := AwaitBucket(context.Background(), refusedBus, refusing, "m_reasks", "x",
+			func(f string, a ...any) { loud = append(loud, fmt.Sprintf(f, a...)) })
+		bound := make(chan struct{})
+		r.Ready(func(jetstream.KeyValue) { close(bound) })
+		if len(loud) != 2 || !strings.Contains(loud[0], "cannot hear the creation of m_reasks") ||
+			!strings.Contains(loud[0], "permissions violation") {
+			t.Fatalf("a refused subscription was said as %q", loud)
+		}
+		refusing.mu.Lock()
+		refusing.refused = false
+		refusing.mu.Unlock()
+		refusedBus.create()
+		refusing.status <- nats.CONNECTED
+		select {
+		case <-bound:
+		case <-time.After(5 * time.Second):
+			t.Fatal("not bound after the connection connected again")
+		}
+		if refusing.subscribed != 2 {
+			t.Errorf("subscribed %d times, want again at the reconnect", refusing.subscribed)
+		}
+
+		// Without the advisory heard, the next use binds it.
+		quiet := &laterBus{}
+		c := AwaitBucket(context.Background(), quiet, nil, "m_hearing", "x", nil)
+		quiet.create()
+		if c.KV() == nil {
+			t.Error("a use after the bucket appeared did not bind it")
+		}
+	})
+
 	for _, tc := range []struct {
 		field  string
 		values map[string]any
@@ -82,3 +181,79 @@ func writeAccount(t *testing.T, fields map[string]any) string {
 	}
 	return path
 }
+
+// refusingBus refuses every bucket with err.
+type refusingBus struct{ err error }
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) { return nil, r.err }
+
+// laterBus has no bucket until create, and then one.
+type laterBus struct {
+	mu sync.Mutex
+	kv *keptKV
+}
+
+func (l *laterBus) create() { l.mu.Lock(); l.kv = &keptKV{}; l.mu.Unlock() }
+
+func (l *laterBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.kv == nil {
+		return nil, jetstream.ErrBucketNotFound
+	}
+	return l.kv, nil
+}
+
+// keptKV records each put as key=value.
+type keptKV struct {
+	jetstream.KeyValue
+	puts []string
+}
+
+func (k *keptKV) Put(_ context.Context, key string, value []byte) (uint64, error) {
+	k.puts = append(k.puts, key+"="+string(value))
+	return uint64(len(k.puts)), nil
+}
+
+// heldSubscriber keeps the last subscription made, for the test to deliver to; refused, the bus refuses it as a
+// *nats.Conn says it (the connection's last error after a round trip). status stands for the connection's CONNECTED.
+type heldSubscriber struct {
+	mu         sync.Mutex
+	subject    string
+	handle     nats.MsgHandler
+	subscribed int
+	refused    bool
+	last       error
+	status     chan nats.Status
+}
+
+func (h *heldSubscriber) Subscribe(subject string, handle nats.MsgHandler) (*nats.Subscription, error) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.subject, h.handle = subject, handle
+	h.subscribed++
+	if h.refused {
+		h.last = fmt.Errorf("%w: Permissions Violation for Subscription to %q", nats.ErrPermissionViolation, subject)
+	}
+	return nil, nil
+}
+
+func (h *heldSubscriber) FlushTimeout(time.Duration) error { return nil }
+
+func (h *heldSubscriber) LastError() error { h.mu.Lock(); defer h.mu.Unlock(); return h.last }
+
+func (h *heldSubscriber) StatusChanged(...nats.Status) chan nats.Status {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.status = make(chan nats.Status, 1)
+	return h.status
+}
+
+func (h *heldSubscriber) RemoveStatusListener(chan nats.Status) {}
+
+func (h *heldSubscriber) deliver() {
+	h.mu.Lock()
+	handle, subject := h.handle, h.subject
+	h.mu.Unlock()
+	handle(&nats.Msg{Subject: subject})
+}

go/process/buckets.go

@@ -0,0 +1,322 @@
+package process
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the delivery
+// builder exited on a refused read of the gate's source and crash-looped). A grant reaches the bus with a delivery, so a
+// bucket, a watch or a consumer the bus refuses, or times out on, at start is often only not granted yet: exiting for it
+// stops the part until a person's hand. A part opens what it cannot do its job at all without with EssentialBucket, which
+// stops its start with an error naming the bucket and its grant, and everything else with OptionalBucket, which says what
+// is not heard and goes on; a watch the bus refuses on an optional bucket is said with NotWatched. Here, beside State,
+// because this is where a process opens what it keeps and reads on the bus; the parts that open buckets with their own
+// JetStream (the delivery parts) take the same three.
+
+// BucketOpener is the part of the bus a start opens buckets with: a jetstream.JetStream, or a test's fake.
+type BucketOpener interface {
+	KeyValue(ctx context.Context, bucket string) (jetstream.KeyValue, error)
+}
+
+// EssentialBucket opens a bucket part cannot work without (it cannot `does` without it); its error is EssentialErr's.
+func EssentialBucket(ctx context.Context, js BucketOpener, part, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, EssentialErr(part, name, does, err)
+	}
+	return kv, nil
+}
+
+// EssentialErr is the error of a bucket, consumer or stream named name that part cannot work without: it says what part
+// cannot do, that it stops, and the grant to look at.
+func EssentialErr(part, name, does string, err error) error {
+	return fmt.Errorf("%s cannot be read (%v): the %s cannot %s without it, so it stops; where the bus refused it or did not "+
+		"answer, this module's grant of %s (its manifest's reads, state or consumes, issued with its credential) has not "+
+		"reached the bus yet", name, err, part, does, name)
+}
+
+// OptionalBucket opens a bucket the part works without: any error is said with what is not heard (without), and nil
+// answered.
+func OptionalBucket(ctx context.Context, js BucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
+
+// NotWatched says that an optional bucket opened but its watch was refused or not answered: what is not heard.
+func NotWatched(logf func(string, ...any), name string, err error, without string) {
+	logf("the bucket %s cannot be watched (%v): %s", name, err, without)
+}
+
+// ErrNotYet is a write to an awaited bucket that is not on the bus yet: the value is kept, the latest per key, and
+// written once the bucket appears.
+var ErrNotYet = errors.New("the bucket is not on the bus yet: the value is kept and written when it appears")
+
+// Subscriber is the part of a connection that hears what the bus says: a *nats.Conn, or a test's fake.
+type Subscriber interface {
+	Subscribe(subject string, handle nats.MsgHandler) (*nats.Subscription, error)
+}
+
+// createdAdvisory is the subject the bus says a bucket's stream was created on: the server's own advisory, which a
+// principal is granted for each bucket it may bind (mesh-sdk buscompose StreamCreatedAdvisory, stateCreatedHeard).
+func createdAdvisory(bucket string) string { return "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_" + bucket }
+
+// bindWithin bounds one bind of an awaited bucket: one STREAM.INFO.
+const bindWithin = 10 * time.Second
+
+// AwaitedBucket is a bucket a part keeps or reads that may not be on the bus at its start, bound once it is (novox/hq
+// issue 1790, met 2026-10-26: since the grants part creates a manifest's buckets after a delivery, ADR 0547, a module
+// restarted by that delivery opened its new state `hearing` before it existed, got "bucket not found", and never looked
+// again). It binds at AwaitBucket when it can; otherwise when the bus says the bucket's stream was created (heard on
+// nc), and at each use before then (one STREAM.INFO, the cheap check), never on a timer. It says once that it waits and
+// once that the bucket appeared.
+type AwaitedBucket struct {
+	ctx     context.Context
+	js      BucketOpener
+	name    string
+	without string
+	logf    func(string, ...any)
+
+	nc Subscriber
+
+	mu          sync.Mutex
+	kv          jetstream.KeyValue
+	refusedSaid bool
+	stopStatus  func()
+	pending     map[string][]byte
+	order       []string
+	ready       []func(jetstream.KeyValue)
+	sub         *nats.Subscription
+}
+
+// AwaitBucket opens the bucket name now if the bus holds it, and otherwise waits for it as AwaitedBucket says; without
+// is what is not done while it is missing. nc may be nil: then only a use binds it. ctx is the part's life: a bind
+// after it ends is not tried.
+func AwaitBucket(ctx context.Context, js BucketOpener, nc Subscriber, name, without string, logf func(string, ...any)) *AwaitedBucket {
+	if logf == nil {
+		logf = func(string, ...any) {}
+	}
+	b := &AwaitedBucket{ctx: ctx, js: js, name: name, without: without, logf: logf, pending: map[string][]byte{}}
+	// Heard before the first try, so a creation between the try and the subscription is not missed.
+	if nc != nil {
+		b.nc = nc
+		b.hear()
+		b.followReconnects()
+	}
+	ctxB, cancel := context.WithTimeout(ctx, bindWithin)
+	kv, err := js.KeyValue(ctxB, name)
+	cancel()
+	if err == nil {
+		b.bound(kv, false)
+		return b
+	}
+	logf("the bucket %s cannot be read yet (%v): %s until it appears; it is bound when the bus says it was created, or at "+
+		"its next use", name, err, without)
+	return b
+}
+
+// KV is the bound bucket, or nil while it is not on the bus; while nil, the call tries to bind it once.
+func (b *AwaitedBucket) KV() jetstream.KeyValue {
+	b.mu.Lock()
+	kv := b.kv
+	b.mu.Unlock()
+	if kv != nil {
+		return kv
+	}
+	return b.bind()
+}
+
+// Ready runs f with the bucket: now when it is bound, otherwise once it appears (on the goroutine that bound it).
+func (b *AwaitedBucket) Ready(f func(jetstream.KeyValue)) {
+	b.mu.Lock()
+	kv := b.kv
+	if kv == nil {
+		b.ready = append(b.ready, f)
+	}
+	b.mu.Unlock()
+	if kv != nil {
+		f(kv)
+	}
+}
+
+// Put writes key, as jetstream.KeyValue's Put. While the bucket is missing it keeps value as key's latest and answers
+// ErrNotYet; the kept values are written, in the order their keys were first kept, when it appears.
+func (b *AwaitedBucket) Put(ctx context.Context, key string, value []byte) (uint64, error) {
+	kv := b.KV()
+	if kv == nil {
+		b.mu.Lock()
+		if b.kv == nil {
+			if _, ok := b.pending[key]; !ok {
+				b.order = append(b.order, key)
+			}
+			b.pending[key] = append([]byte(nil), value...)
+			b.mu.Unlock()
+			return 0, fmt.Errorf("%s: %w", b.name, ErrNotYet)
+		}
+		kv = b.kv
+		b.mu.Unlock()
+	}
+	return kv.Put(ctx, key, value)
+}
+
+// bind tries one STREAM.INFO of the bucket and, when it is there, binds it; it answers the bucket or nil.
+func (b *AwaitedBucket) bind() jetstream.KeyValue {
+	if b.ctx.Err() != nil {
+		return nil
+	}
+	ctx, cancel := context.WithTimeout(b.ctx, bindWithin)
+	defer cancel()
+	kv, err := b.js.KeyValue(ctx, b.name)
+	if err != nil {
+		return nil
+	}
+	return b.bound(kv, true)
+}
+
+// bound keeps kv as the bucket (unless another bind did first), writes what was kept and runs what waited on it.
+func (b *AwaitedBucket) bound(kv jetstream.KeyValue, appeared bool) jetstream.KeyValue {
+	b.mu.Lock()
+	if b.kv != nil {
+		kv = b.kv
+		b.mu.Unlock()
+		return kv
+	}
+	// The kept values are written before the bucket is handed to anyone, so no later write is overtaken by an earlier.
+	written, failed := 0, 0
+	for _, key := range b.order {
+		ctx, cancel := context.WithTimeout(b.ctx, bindWithin)
+		_, err := kv.Put(ctx, key, b.pending[key])
+		cancel()
+		if err != nil {
+			failed++
+			b.logf("the bucket %s appeared but the value kept for %s could not be written: %v", b.name, key, err)
+			continue
+		}
+		written++
+	}
+	b.kv, b.pending, b.order = kv, nil, nil
+	ready, sub, stop := b.ready, b.sub, b.stopStatus
+	b.ready, b.sub, b.stopStatus = nil, nil, nil
+	b.mu.Unlock()
+	if sub != nil {
+		_ = sub.Unsubscribe()
+	}
+	if stop != nil {
+		stop()
+	}
+	if appeared {
+		b.logf("the bucket %s appeared and is bound: %d kept value(s) written, %d not", b.name, written, failed)
+	}
+	for _, f := range ready {
+		f(kv)
+	}
+	return kv
+}
+
+// refusalReader is the part of a *nats.Conn that says whether the bus refused a subscription: the server's refusal comes
+// back after a round trip as the connection's last error, naming the subject.
+type refusalReader interface {
+	FlushTimeout(time.Duration) error
+	LastError() error
+}
+
+// statusFollower is the part of a *nats.Conn that says when it connected again, without taking its reconnect handler.
+type statusFollower interface {
+	StatusChanged(statuses ...nats.Status) chan nats.Status
+	RemoveStatusListener(ch chan nats.Status)
+}
+
+// hear subscribes to the bucket's creation (again), and says once, loudly, when the bus refuses it: then only a use or
+// a reconnect binds the bucket.
+func (b *AwaitedBucket) hear() {
+	subject := createdAdvisory(b.name)
+	b.mu.Lock()
+	old, bound := b.sub, b.kv != nil
+	b.sub = nil
+	b.mu.Unlock()
+	if old != nil {
+		_ = old.Unsubscribe()
+	}
+	if bound {
+		return
+	}
+	checks, _ := b.nc.(refusalReader)
+	var before error
+	if checks != nil {
+		before = checks.LastError()
+	}
+	sub, err := b.nc.Subscribe(subject, func(*nats.Msg) { go b.bind() })
+	if err == nil && checks != nil && checks.FlushTimeout(bindWithin) == nil {
+		if after := checks.LastError(); after != nil && after != before && errors.Is(after, nats.ErrPermissionViolation) &&
+			strings.Contains(after.Error(), subject) {
+			err = after
+		}
+	}
+	if err != nil {
+		if sub != nil {
+			_ = sub.Unsubscribe()
+		}
+		b.mu.Lock()
+		said := b.refusedSaid
+		b.refusedSaid = true
+		b.mu.Unlock()
+		if !said {
+			b.logf("cannot hear the creation of %s: %v; it binds at its next use, or when the connection reconnects", b.name, err)
+		}
+		return
+	}
+	b.mu.Lock()
+	if b.kv != nil {
+		b.mu.Unlock()
+		if sub != nil {
+			_ = sub.Unsubscribe()
+		}
+		return
+	}
+	b.sub, b.refusedSaid = sub, false
+	b.mu.Unlock()
+}
+
+// followReconnects hears the bucket's creation again and tries a bind each time the connection connects again (a grant
+// reaches the bus with a new user list; a lost subscription is made again), until the bucket is bound or the part ends.
+func (b *AwaitedBucket) followReconnects() {
+	w, ok := b.nc.(statusFollower)
+	if !ok {
+		return
+	}
+	ch := w.StatusChanged(nats.CONNECTED)
+	b.mu.Lock()
+	if b.kv != nil {
+		b.mu.Unlock()
+		w.RemoveStatusListener(ch)
+		return
+	}
+	b.stopStatus = func() { w.RemoveStatusListener(ch) }
+	b.mu.Unlock()
+	go func() {
+		for {
+			select {
+			case <-b.ctx.Done():
+				w.RemoveStatusListener(ch)
+				return
+			case _, open := <-ch:
+				if !open {
+					return
+				}
+				b.hear()
+				b.KV()
+			}
+		}
+	}()
+}

go/process/fixture_integration_test.go

@@ -57,8 +57,10 @@ func grantedSendProcess(t *testing.T) (url string, account Account) {
 		Users: []*server.User{
 			{Username: adminUser, Password: adminPass},
 			{Username: sendUser, Password: sendPassword, Permissions: &server.Permissions{
-				Publish:   &server.SubjectPermission{Allow: sendGrants},
-				Subscribe: &server.SubjectPermission{Allow: []string{"_INBOX." + sendUser + ".>"}},
+				Publish: &server.SubjectPermission{Allow: sendGrants},
+				// And the creation of its bucket, as mesh-sdk's composer grants it since issue 1790 (stateCreatedHeard).
+				Subscribe: &server.SubjectPermission{Allow: []string{"_INBOX." + sendUser + ".>",
+					"$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-mail_sends"}},
 			}},
 		},
 	}

go/process/state_integration_test.go

@@ -18,12 +18,40 @@ import (
 // key, reads it, and updates it with the revision it read, then each succeeds and returns the new
 // revision; an update with a stale revision fails as stdio.ErrChanged; a create of an existing key fails
 // as stdio.ErrChanged.
+//
+// 1790: and before that, the bucket is not on the bus when the process opens it (a delivery restarted it before the
+// grants part created its new state): it is bound when the bus says the bucket was created, as the process's own
+// account hears it, and the value written while it was missing is there.
 func TestStateCreateGetUpdateOnAGrantedBucket(t *testing.T) {
 	url, account := grantedSendProcess(t)
 	_, adminJetStream := adminJS(t, url)
+
+	nc, err := nats.Connect(url, nats.UserInfo(sendUser, sendPassword), nats.CustomInboxPrefix("_INBOX."+sendUser))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	js, err := jetstream.New(nc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	awaited := AwaitBucket(ctxFor(t), js, nc, "mesh-mail_sends", "nothing is kept", t.Logf)
+	appeared := make(chan struct{})
+	awaited.Ready(func(jetstream.KeyValue) { close(appeared) })
+	if _, err := awaited.Put(ctxFor(t), "hearing", []byte(`{"heard":false}`)); !errors.Is(err, ErrNotYet) {
+		t.Fatalf("a write before the bucket exists: %v, want ErrNotYet", err)
+	}
+	if _, err := awaited.Put(ctxFor(t), "hearing", []byte(`{"heard":true}`)); !errors.Is(err, ErrNotYet) {
+		t.Fatalf("a second write before the bucket exists: %v, want ErrNotYet", err)
+	}
 	if _, err := adminJetStream.CreateKeyValue(ctxFor(t), jetstream.KeyValueConfig{Bucket: "mesh-mail_sends"}); err != nil {
 		t.Fatalf("the admin could not make the bucket: %v", err)
 	}
+	select {
+	case <-appeared:
+	case <-time.After(5 * time.Second):
+		t.Fatal("the bucket was not bound within 5s of its creation, with no use since")
+	}
 
 	conn, err := Connect(account)
 	if err != nil {
@@ -31,6 +59,9 @@ func TestStateCreateGetUpdateOnAGrantedBucket(t *testing.T) {
 	}
 	defer conn.Close()
 	s := conn.State("sends")
+	if kept, err := s.Get("hearing"); err != nil || kept == nil || string(kept.Value) != `{"heard":true}` {
+		t.Fatalf("the value written while the bucket was missing: %+v, %v; want the latest", kept, err)
+	}
 
 	rev, err := s.Create("key", map[string]any{"v": 1})
 	if err != nil {