A runtime that already dropped a carried module's tools serves them again, read from what runs and its build (issue 1126, review)

rev-held2: ToolsRunning took a carried module's bundles from the runtime's MESH_TOOL_MODULES alone, and shanks had
already applied the drop of systemd-resolved, so its runs stayed empty and the drop permanent. Now every bundle
archive that runs at its module's BundlePath is a running bundle; one the runtime loads nothing of takes its loads and
words from the module's build (its built bundles, else its build's artifacts, by catalogue.BundleLoads, the rule a
build's resolution keeps, now one function). The runtime process and each archive are matched by their owning module
too, not only by id and path. A row added: the runtime already dropped it.

go/asks/asks.go

@@ -571,3 +571,8 @@ type ProofAnswer struct {
 	Accepted bool   `json:"accepted"`
 	Words    string `json:"words"`
 }
+
+// EngineAsker is the asker name a node's engine asks the operator under (novox/hq ADR 0563 §3, which changes ADR 0259
+// §2 to admit a node's engine as an asker): `node-engine-<node>`, the last token of the by-caller subjects granted to that
+// node's engine account alone, so no engine acts on another node's warrant.
+func EngineAsker(node string) string { return "node-engine-" + node }

go/buscompose/accounts.go

@@ -0,0 +1,244 @@
+package buscompose
+
+import (
+	"encoding/json"
+	"fmt"
+	"slices"
+	"strings"
+	"time"
+)
+
+// **The accounts the grants part wants, and the one shape a held account takes** (novox/hq ADR 0561 §1, §2; issue 774).
+//
+// The bus composer derives every user from placement, the manifests and the wants. For each account the mesh mints (a
+// module's, a module's process's, a machine's provisioner client's), the grants part writes one key of its state
+// `accounts`, keyed by the bus user, holding the account's fields that are not secret: what the controller's credential
+// carries today beside the password. The vault watches that state, mints the user it holds no value for, and keeps the
+// value as the module's own secret on that node, built by HeldCredential, which gives byte for byte the controller's
+// shape, so a runtime reads it unchanged. The state is read by the vault alone (NamedReaders), as `bus-accounts` is read
+// by the grants part alone.
+//
+// The node accounts, the controller's own, an enrolment user and a person are never wanted here: the vault mints none
+// of them (ADR 0561 §4, §5).
+
+// AccountsState is the grants part's state of wanted accounts, by bus user.
+const AccountsState = "accounts"
+
+// GrantsAccounts is that state as a reader names it (`<owner>.<name>`).
+const GrantsAccounts = GrantsModule + "." + AccountsState
+
+// AccountsBucket is the bucket the state lives in.
+var AccountsBucket = BucketName(GrantsModule, AccountsState)
+
+// AccountsSubject is the subject of one wanted account's key: `$KV.mesh-grants_accounts.<user>`.
+func AccountsSubject(user string) string { return "$KV." + AccountsBucket + "." + user }
+
+// AccountIssuedEvent is what the vault says when it minted an account: AccountIssued, never a value or a hash.
+const AccountIssuedEvent = "account-issued"
+
+// AccountIssuedSubject is where it says it, as the runtime addresses mesh-vault's events.
+const AccountIssuedSubject = "mesh.mod." + VaultSeat + ".event." + AccountIssuedEvent
+
+// ClaimedSeat is one seat a module claims, as its runtime needs it (the controller's seatClaimed): the name, the scope (a
+// node-scoped seat's verb carries the machine) and the verbs the runtime serves for it.
+type ClaimedSeat struct {
+	Seat   string   `json:"seat"`
+	Scope  string   `json:"scope"`
+	Serves []string `json:"serves,omitempty"`
+}
+
+// WantedAccount is one key of the grants part's state `accounts`: an account the mesh needs, without its password.
+type WantedAccount struct {
+	User string `json:"user"`
+	// Kind is KindModule (KindNodeTools for the runtime, named as a module is), KindProcess or KindProvisioner.
+	Kind   Kind   `json:"kind"`
+	Node   string `json:"node"`
+	Module string `json:"module"`
+	// Process is a KindProcess account's process id.
+	Process string `json:"process,omitempty"`
+	// URL is the bus's address as that node reaches it, `nats://<host>:<port>`; Fingerprint the bus certificate's.
+	URL         string `json:"url"`
+	Fingerprint string `json:"fingerprint,omitempty"`
+	// Claims are a module's claims with the verbs each seat promises: none for a process or a provisioner client.
+	Claims []ClaimedSeat `json:"claims,omitempty"`
+	// At is when the grants part wrote the key: not compared (Same).
+	At time.Time `json:"at"`
+}
+
+// mintedKinds are the kinds of account the vault mints (ADR 0561 §1).
+var mintedKinds = []Kind{KindModule, KindNodeTools, KindProcess, KindProvisioner}
+
+// principal is the account as the composer names it.
+func (w WantedAccount) principal() Principal {
+	return Principal{Kind: w.Kind, Node: w.Node, Module: w.Module, Process: w.Process}
+}
+
+// Valid says why w is not an account the vault may mint, or nil: a kind it mints, every name a subject token, the user
+// the one the composer derives from them, and an address to reach the bus at.
+func (w WantedAccount) Valid() error {
+	if !slices.Contains(mintedKinds, w.Kind) {
+		return fmt.Errorf("%s is a %s account, which the vault never mints (ADR 0561 §4)", w.User, w.Kind)
+	}
+	for what, v := range map[string]string{"node": w.Node, "module": w.Module} {
+		if !safeSubject.MatchString(v) {
+			return fmt.Errorf("%s: the %s %q is not a name the mesh writes", w.User, what, v)
+		}
+	}
+	if w.Kind == KindProcess && !safeSubject.MatchString(w.Process) {
+		return fmt.Errorf("%s: the process %q is not a name the mesh writes", w.User, w.Process)
+	}
+	if w.Kind != KindProcess && w.Process != "" {
+		return fmt.Errorf("%s: only a process's account names a process", w.User)
+	}
+	if want := w.principal().Username(); w.User != want {
+		return fmt.Errorf("%s is not the user of a %s account of %s on %s (that is %s)", w.User, w.Kind, w.Module, w.Node, want)
+	}
+	if !strings.HasPrefix(w.URL, "nats://") || len(w.URL) == len("nats://") {
+		return fmt.Errorf("%s names no bus address (url, nats://<host>:<port>)", w.User)
+	}
+	if len(w.Claims) > 0 && w.Kind != KindModule && w.Kind != KindNodeTools {
+		return fmt.Errorf("%s: a %s account holds no seat, so it carries no claims", w.User, w.Kind)
+	}
+	return nil
+}
+
+// Same says whether two wanted accounts want the same account: every field but when it was written.
+func (w WantedAccount) Same(o WantedAccount) bool {
+	a, b := w, o
+	a.At, b.At = time.Time{}, time.Time{}
+	ra, _ := json.Marshal(a)
+	rb, _ := json.Marshal(b)
+	return string(ra) == string(rb)
+}
+
+// OwnSecret is the module's own secret the account is held in: `broker`, `broker-<process id>` or `provisioner-broker`
+// (the controller's names, ADR 0436 §2, ADR 0349 §11).
+func (w WantedAccount) OwnSecret() string {
+	switch w.Kind {
+	case KindProcess:
+		return "broker-" + w.Process
+	case KindProvisioner:
+		return "provisioner-broker"
+	}
+	return "broker"
+}
+
+// ReadWantedAccount reads the key user of the state: refused when it is not a valid wanted account of that user.
+func ReadWantedAccount(user string, raw []byte) (WantedAccount, error) {
+	var w WantedAccount
+	if err := json.Unmarshal(raw, &w); err != nil {
+		return WantedAccount{}, fmt.Errorf("%s %s is not a wanted account: %w", GrantsAccounts, user, err)
+	}
+	if w.User != user {
+		return WantedAccount{}, fmt.Errorf("%s %s names the user %q", GrantsAccounts, user, w.User)
+	}
+	return w, w.Valid()
+}
+
+// AccountIssued is the vault's account-issued: which account it minted, and its generation. Never a value or a hash.
+type AccountIssued struct {
+	User       string    `json:"user"`
+	Kind       Kind      `json:"kind"`
+	Node       string    `json:"node"`
+	Module     string    `json:"module"`
+	Process    string    `json:"process,omitempty"`
+	Generation int       `json:"generation"`
+	At         time.Time `json:"at"`
+}
+
+// HeldCredential is the value the account's holder reads, exactly as the controller builds it today (issueWith,
+// sealProcess and sealProvisionerClient): a module's `{url, fingerprint, node, module, user, password, claims}`, a
+// process's without claims, a provisioner client's without module or claims; an empty fingerprint or claims left out.
+func HeldCredential(w WantedAccount, password string) ([]byte, error) {
+	if err := w.Valid(); err != nil {
+		return nil, err
+	}
+	if password == "" {
+		return nil, fmt.Errorf("%s: an account is held with its password", w.User)
+	}
+	switch w.Kind {
+	case KindProcess:
+		return json.Marshal(struct {
+			URL         string `json:"url"`
+			Fingerprint string `json:"fingerprint,omitempty"`
+			Node        string `json:"node"`
+			Module      string `json:"module"`
+			User        string `json:"user"`
+			Password    string `json:"password"`
+		}{URL: w.URL, Fingerprint: w.Fingerprint, Node: w.Node, Module: w.Module, User: w.User, Password: password})
+	case KindProvisioner:
+		return json.Marshal(struct {
+			URL         string `json:"url"`
+			Fingerprint string `json:"fingerprint,omitempty"`
+			Node        string `json:"node"`
+			User        string `json:"user"`
+			Password    string `json:"password"`
+		}{URL: w.URL, Fingerprint: w.Fingerprint, Node: w.Node, User: w.User, Password: password})
+	}
+	return json.Marshal(struct {
+		URL         string        `json:"url"`
+		Fingerprint string        `json:"fingerprint,omitempty"`
+		Node        string        `json:"node"`
+		Module      string        `json:"module"`
+		User        string        `json:"user"`
+		Password    string        `json:"password"`
+		Claims      []ClaimedSeat `json:"claims,omitempty"`
+	}{URL: w.URL, Fingerprint: w.Fingerprint, Node: w.Node, Module: w.Module, User: w.User, Password: password,
+		Claims: w.Claims})
+}
+
+// **One issuer at every moment: minting turns on at the lease write** (novox/hq ADR 0561 §3, §6). The controller's lease
+// is the one key `holder` of its bucket (LeaseBucket). The operator's credential hands it away by writing a value that
+// names its new holder in `handed-to`; while the key holds that, the vault mints and the grants part creates the durable
+// consumers an account needs. A controller's value, a key deleted or expired, or one that cannot be read or parsed, turn
+// both off: when in doubt nothing is minted, so the controller and the vault never both mint one account. No clock and
+// no setting turns it.
+
+// ControllerLease is the lease's bucket as a reader names it; the vault and the grants part alone read it
+// (NamedReaders), the controller's announcement marking it readable by nobody.
+const ControllerLease = ControllerSeat + ".lease"
+
+// ControllerLeaseKey is the lease's one key.
+const ControllerLeaseKey = leaseKey
+
+// LeaseHolder is the lease key's value: a controller instance's (mesh-controller internal/lease Holder), or, once handed
+// away, one naming its holder in HandedTo.
+type LeaseHolder struct {
+	Instance string    `json:"instance,omitempty"`
+	Host     string    `json:"host,omitempty"`
+	Epoch    uint64    `json:"epoch,omitempty"`
+	Taken    time.Time `json:"taken,omitzero"`
+	Renewed  time.Time `json:"renewed,omitzero"`
+	// HandedTo is who holds the lease once the controller handed it away: never a controller instance.
+	HandedTo string `json:"handed-to,omitempty"`
+	// HandedBy is the credential that wrote it (the operator's), and Why its reason.
+	HandedBy string `json:"handed-by,omitempty"`
+	Why      string `json:"why,omitempty"`
+}
+
+// LeaseHandedAway reads the lease key as a getter answered it (its value, whether it was there, the read's error) and
+// says whether it is handed to a holder that is no controller, with why either way.
+func LeaseHandedAway(raw []byte, found bool, readErr error) (bool, string) {
+	switch {
+	case readErr != nil:
+		return false, "the controller's lease cannot be read (" + readErr.Error() + "), so nothing is minted"
+	case !found || len(raw) == 0 || string(raw) == "null":
+		return false, "no lease is written (expired, deleted, or never taken): a controller may take it, so nothing is minted"
+	}
+	var h LeaseHolder
+	if err := json.Unmarshal(raw, &h); err != nil {
+		return false, "the controller's lease is not readable as a holder (" + err.Error() + "), so nothing is minted"
+	}
+	if strings.TrimSpace(h.HandedTo) == "" {
+		who := h.Instance
+		if who == "" {
+			who = "an instance that names itself not"
+		}
+		return false, "the controller holds the lease (" + who + "): it mints, so the vault mints nothing (ADR 0561 §3)"
+	}
+	if h.Instance != "" {
+		return false, "the lease names both a controller instance (" + h.Instance + ") and a holder it is handed to (" +
+			h.HandedTo + "), so nothing is minted"
+	}
+	return true, "the lease is handed to " + h.HandedTo + ": the vault mints every new account (ADR 0561 §1, §3)"
+}

go/buscompose/announced.go

@@ -1,6 +1,7 @@
 package buscompose
 
 import (
+	"slices"
 	"sort"
 	"strings"
 
@@ -58,6 +59,10 @@ func ReadsAnnouncedBy(reader string, reads []string, announced map[string]announ
 		switch {
 		case reader != "" && !ReaderMay(reader, r):
 			refused = append(refused, r)
+		case reader != "" && namedReader(reader, r):
+			// A state the composer names its readers for is theirs whatever its owner announced (ADR 0561 §3: the
+			// controller's lease, which its announcement marks readable by nobody).
+			granted = append(granted, r)
 		case reader != "" && ok && said && s.Keeps(name):
 			if s.ReadableBy(name, reader) {
 				granted = append(granted, r)
@@ -95,3 +100,8 @@ func NotAnnounced(r Records) []string {
 	sort.Strings(out)
 	return out
 }
+
+// namedReader says the composer names module among the readers of read (NamedReaders).
+func namedReader(module, read string) bool {
+	return slices.Contains(NamedReaders[strings.TrimSpace(read)], module)
+}

go/buscompose/buscompose_test.go

@@ -2,6 +2,7 @@ package buscompose
 
 import (
 	"encoding/json"
+	"errors"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -9,8 +10,11 @@ import (
 	"slices"
 	"strings"
 	"testing"
+	"time"
 
+	"git.novox.be/novox/mesh-sdk/go/announce"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"github.com/nats-io/nats.go/jetstream"
 )
 
 // Defends issue 1377 and novox/hq ADR 0547 §5: this is the controller's bus composer copied, and it composes byte for
@@ -51,6 +55,26 @@ func mayBeyondTheControllers(user string) map[string]bool {
 		VaultSecretChanged: true}
 }
 
+// engineBeyond is a node's engine holding its node seat and asking the operator in its own name (novox/hq ADR 0563 §1,
+// §3), beyond the controller's on purpose: its own node's verbs, events and discovery, the bus's discovery asked, and
+// the router's seat traffic under node-engine-<node>.
+func engineBeyond(user, g string) bool {
+	node, ok := strings.CutPrefix(user, "node.")
+	if !ok {
+		return false
+	}
+	return strings.HasPrefix(g, "mesh.seat."+EngineSeat+".") && strings.Contains(g, "."+node) ||
+		strings.HasPrefix(g, "$SRV.") || strings.Contains(g, ".node-engine-"+node) ||
+		strings.Contains(g, "KV_"+EngineActsBucket) || strings.HasPrefix(g, "$KV."+EngineActsBucket+"."+node+".")
+}
+
+// createsAnAccountsConsumer is the grants part's create and read of a durable consumer an account needs, by its stream
+// and name (novox/hq ADR 0561 §6): beyond the controller's on purpose, since the controller made them alone.
+func createsAnAccountsConsumer(user, g string) bool {
+	return strings.HasSuffix(user, "."+GrantsModule) &&
+		(strings.HasPrefix(g, "$JS.API.CONSUMER.CREATE.") || strings.HasPrefix(g, "$JS.API.CONSUMER.INFO."))
+}
+
 // quotedToken is a quoted token of a composed list.
 var quotedToken = regexp.MustCompile(`"[^"]*"`)
 
@@ -102,7 +126,8 @@ func grantsAsTheControllers(t *testing.T, got, want string) {
 			}
 		}
 		for g := range now {
-			if !was[g] && !intended[g] && !mayBeyondTheControllers(user)[g] && !createdAdvisory.MatchString(`"`+g+`", `) {
+			if !was[g] && !intended[g] && !mayBeyondTheControllers(user)[g] && !createdAdvisory.MatchString(`"`+g+`", `) &&
+				!createsAnAccountsConsumer(user, g) && !engineBeyond(user, g) {
 				t.Errorf("%s: the copy grants %s beyond the controller's, and no decision names it", user, g)
 			}
 		}
@@ -119,6 +144,8 @@ func grantsAsTheControllers(t *testing.T, got, want string) {
 	}
 }
 
+const SignersBucketName = "mesh-vault_signers"
+
 func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 	// ADR 0567 §3, §9: a node reads every key of the seat's placement and its candidates (it composes with the whole
 	// proposal laid over), and none of its open proposals; it writes neither.
@@ -221,6 +248,55 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 			t.Error("a user of a seat not pulled by kind reads DEAD_LETTERS")
 		}
 	})
+	// ADR 0563 §1, §3, §6: each node's engine alone answers its own node's node-engine verbs and says its events, any
+	// runtime may call them, and it asks the operator under node-engine-<node> alone.
+	t.Run("a node's engine holds its node seat and asks in its own name", func(t *testing.T) {
+		router := Seat{Name: AsksSeat, Accepts: []string{"ask", "cancel"}, Emits: []string{"decided"},
+			ByCaller: []string{"ask", "cancel", "decided"}, Records: []string{"messenger_asks"}}
+		users, err := Users(Records{Nodes: []string{"one", "two"}, Assigned: map[string][]Declared{
+			"one": {{Module: "messenger", Holds: []Seat{router}, Invokes: []string{"seat:" + EngineSeat + ".root-free"}}},
+			"two": {{Module: RuntimeModule}, {Module: "shop", Invokes: []string{"*"}}}}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, u := range users {
+			perms, err := PermissionsFor(u)
+			if err != nil {
+				t.Fatal(err)
+			}
+			answers := MaySubscribe(perms, "mesh.seat."+EngineSeat+".tool.root-free.one") ||
+				MaySubscribe(perms, "mesh.seat."+EngineSeat+".call.root-free.one.messenger~one")
+			if engineOne := u.Kind == KindNode && u.Node == "one"; answers != engineOne {
+				t.Errorf("%s answers one's root-free: %v", u.Username(), answers)
+			}
+			switch {
+			case u.Kind == KindNode && u.Node == "one":
+				for subject, want := range map[string]bool{
+					"mesh.seat.operator-channel.accept.ask.node-engine-one":                               true,
+					"mesh.seat.operator-channel.accept.cancel.node-engine-one":                            true,
+					"mesh.seat.operator-channel.accept.ask.node-engine-two":                               false,
+					"$JS.API.DIRECT.GET.KV_messenger_asks.$KV.messenger_asks.node-engine-one.hand-over-1": true,
+					"$JS.API.DIRECT.GET.KV_messenger_asks.$KV.messenger_asks.node-engine-two.hand-over-1": false,
+					"mesh.seat." + EngineSeat + ".event.done.one":                                         true,
+					"mesh.seat." + EngineSeat + ".event.done.two":                                         false,
+					"$SRV.INFO": true,
+				} {
+					if got := MayPublish(perms, subject); got != want {
+						t.Errorf("node one may publish %s: %v, want %v", subject, got, want)
+					}
+				}
+				if !MaySubscribe(perms, "mesh.seat.operator-channel.event.decided.node-engine-one") ||
+					MaySubscribe(perms, "mesh.seat.operator-channel.event.decided.node-engine-two") ||
+					!MaySubscribe(perms, "$SRV.INFO."+EngineSeat) || MaySubscribe(perms, "mesh.seat."+EngineSeat+".tool.hand-over.two") {
+					t.Errorf("node one hears %v", perms.Subscribe)
+				}
+			case u.Kind == KindNodeTools || u.Module == "messenger":
+				if !MayPublish(perms, "mesh.seat."+EngineSeat+".tool.root-free.one") {
+					t.Errorf("%s cannot call one's root-free", u.Username())
+				}
+			}
+		}
+	})
 	// Issue 1126 (ADR 0550 §5): a node's engine asks the vault's `own` in its own name while the vault serves it, and no
 	// other node's.
 	t.Run("a node asks the vault its own secrets", func(t *testing.T) {
@@ -239,6 +315,21 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 		if !slices.Contains(perms.Subscribe, VaultSecretChanged) {
 			t.Errorf("node one does not hear the vault's secret-changed: %v", perms.Subscribe)
 		}
+		// L3 s6 (ADR 0550 §2): while the vault serves `sign`, a node asks it in its own name alone, and reads the vault's
+		// `signers` and the lease key, never writing either.
+		signs, _ := PermissionsFor(Principal{Kind: KindNode, Node: "one", AsksTheVaultToSign: true})
+		signersGet := "$JS.API.DIRECT.GET.KV_" + SignersBucketName + ".$KV." + SignersBucketName + ".key"
+		leaseGet := "$JS.API.DIRECT.GET.KV_" + LeaseBucket + ".$KV." + LeaseBucket + ".holder"
+		for subject, want := range map[string]bool{VaultSignCall(one): true, signersGet: true, leaseGet: true,
+			VaultSignCall(Principal{Kind: KindNode, Node: "two"}): false, "$KV." + SignersBucketName + ".key": false,
+			"$KV." + LeaseBucket + ".holder": false} {
+			if MayPublish(signs, subject) != want {
+				t.Errorf("a node asking sign may publish %s: %v, want %v", subject, !want, want)
+			}
+		}
+		if MayPublish(perms, VaultSignCall(one)) || MayPublish(perms, signersGet) {
+			t.Error("a node asks sign or reads signers while the vault does not serve sign")
+		}
 		// And what a module on another node serves from its settings, that key alone (mailu's smtp domain, issue 1126).
 		users, err := Users(Records{Nodes: []string{"one", "two"}, Assigned: map[string][]Declared{
 			"two": {{Module: "mailer", Served: []string{"domain", "not.a.token"}}}}})
@@ -293,4 +384,174 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 		}
 		grantsAsTheControllers(t, got, string(want))
 	})
+	// 774/AC2 (novox/hq ADR 0561 §2): a wanted account round-trips through the grants part's state `accounts`, keyed by
+	// its user, at the subject `$KV.mesh-grants_accounts.<user>`, read by the vault alone; and the vault's account-issued
+	// names the account, never a value.
+	t.Run("a wanted account is kept by its user and read by the vault alone", func(t *testing.T) {
+		for _, w := range []WantedAccount{
+			{User: "ace.mesh-build-go", Kind: KindModule, Node: "ace", Module: "mesh-build-go", URL: "nats://novox.mesh:4222",
+				Fingerprint: "ab", Claims: []ClaimedSeat{{Seat: "node-build-go", Scope: "node", Serves: []string{"build"}}}},
+			{User: "novox.mesh-mail.send", Kind: KindProcess, Node: "novox", Module: "mesh-mail", Process: "send",
+				URL: "nats://novox.mesh:4222"},
+			{User: "provisioner.g14", Kind: KindProvisioner, Node: "g14", Module: "mesh-provisioner-client",
+				URL: "nats://novox.mesh:4222", Fingerprint: "ab"},
+		} {
+			if err := w.Valid(); err != nil {
+				t.Fatalf("%s: %v", w.User, err)
+			}
+			raw, err := json.Marshal(w)
+			if err != nil {
+				t.Fatal(err)
+			}
+			back, err := ReadWantedAccount(w.User, raw)
+			if err != nil || !back.Same(w) {
+				t.Errorf("%s does not round-trip: %+v, %v", w.User, back, err)
+			}
+			if got := AccountsSubject(w.User); got != "$KV.mesh-grants_accounts."+w.User {
+				t.Errorf("%s is kept at %s", w.User, got)
+			}
+			if _, err := ReadWantedAccount("someone.else", raw); err == nil {
+				t.Errorf("%s was read under another user's key", w.User)
+			}
+		}
+		for _, bad := range []WantedAccount{
+			{User: "ace.x", Kind: KindModule, Node: "ace", Module: "y", URL: "nats://a:1"},
+			{User: "ace.x.p", Kind: KindProcess, Node: "ace", Module: "x", URL: "nats://a:1"},
+			{User: "node.ace", Kind: KindNode, Node: "ace", URL: "nats://a:1"},
+			{User: "controller", Kind: KindController, URL: "nats://a:1"},
+			{User: "ace.x", Kind: KindModule, Node: "ace", Module: "x"},
+		} {
+			if bad.Valid() == nil {
+				t.Errorf("%+v is taken as a wanted account", bad)
+			}
+		}
+		if ReaderMay("mesh-delivery-assigner", GrantsAccounts) || !ReaderMay(VaultSeat, GrantsAccounts) {
+			t.Errorf("%s is read by %v alone, want the vault's", GrantsAccounts, NamedReaders[GrantsAccounts])
+		}
+		e := AccountIssued{User: "ace.x", Kind: KindModule, Node: "ace", Module: "x", Generation: 1}
+		raw, _ := json.Marshal(e)
+		if strings.Contains(string(raw), "password") || strings.Contains(string(raw), "hash") ||
+			AccountIssuedSubject != "mesh.mod.mesh-vault.event.account-issued" {
+			t.Errorf("account-issued says %s at %s", raw, AccountIssuedSubject)
+		}
+	})
+	// 774/AC3 (novox/hq ADR 0561 §2): the account the vault seals is, byte for byte, what the controller hands for each of
+	// its three kinds: testdata/controller-credentials.json was written by the controller's own code (its "how").
+	t.Run("a held account is the controller's shape byte for byte", func(t *testing.T) {
+		raw, err := os.ReadFile(filepath.Join("testdata", "controller-credentials.json"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		var captured struct {
+			Rows []struct{ Name, Held string }
+		}
+		if err := json.Unmarshal(raw, &captured); err != nil {
+			t.Fatal(err)
+		}
+		vault := ClaimedSeat{Seat: "mesh-vault", Scope: "mesh", Serves: []string{"get", "accept", "secret-ask", "issued",
+			"rotate", "move-in", "node-key", "own", "move-asks"}}
+		controller := ClaimedSeat{Seat: "mesh-controller", Scope: "mesh", Serves: strings.Split("tools,calls,status,nodes,"+
+			"node,placement-export,modules,seats,builds,plans,delivery-plan,delivery-order,delivery-check,deliver,"+
+			"delivery-stop,delivery-backups-again,delivery-walks,plan,assign,unassign,pin,unpin,push,rotate,give,issued,"+
+			"secret-move,secret-ask,issue,token,settings,command,queue,cancel,clear,replay,try,kill,pause,resume,hand-act,"+
+			"drill,warranted,hand-acts,durations,conditions,healers,doctor,upgrade,bus,retire,cleanup,judge-directories,"+
+			"root-free,dead-letters,data,build,artifacts,held,collect,move-placement,move-config,mirrors,images", ",")}
+		at := "nats://10.0.0.1:4222"
+		wanted := map[string]struct {
+			w        WantedAccount
+			password string
+		}{
+			"module": {WantedAccount{User: "laptop.cap-bot", Kind: KindModule, Node: "laptop", Module: "cap-bot", URL: at,
+				Fingerprint: "ab:cd", Claims: []ClaimedSeat{vault, {Seat: "node-service-manager", Scope: "node",
+					Serves: []string{"status"}}, controller, {Seat: "no-such-seat", Scope: "node"}}}, "pw-module"},
+			"module-no-claims-no-fingerprint": {WantedAccount{User: "laptop.cap-plain", Kind: KindModule, Node: "laptop",
+				Module: "cap-plain", URL: at}, "pw-plain"},
+			"provisioner": {WantedAccount{User: "provisioner.laptop", Kind: KindProvisioner, Node: "laptop", Module: "nats",
+				URL: at, Fingerprint: "ab:cd"}, "pw-prov"},
+			"process": {WantedAccount{User: "laptop.mesh-mail.send", Kind: KindProcess, Node: "laptop", Module: "mesh-mail",
+				Process: "send", URL: at, Fingerprint: "ab:cd"}, "pw-proc"},
+		}
+		if len(captured.Rows) != len(wanted) {
+			t.Fatalf("%d rows captured, %d wanted", len(captured.Rows), len(wanted))
+		}
+		for _, row := range captured.Rows {
+			c, ok := wanted[row.Name]
+			if !ok {
+				t.Fatalf("no wanted account for the captured %s", row.Name)
+			}
+			got, err := HeldCredential(c.w, c.password)
+			if err != nil || string(got) != row.Held {
+				t.Errorf("%s:\n got %s (%v)\nwant %s", row.Name, got, err, row.Held)
+			}
+		}
+		if _, err := HeldCredential(wanted["module"].w, ""); err == nil {
+			t.Error("an account was held with no password")
+		}
+	})
+	// 774 subtasks 6 and 8 (novox/hq ADR 0561 §3, §6): minting and the grants part's consumers turn on only while the
+	// lease is handed to a holder that is no controller; the vault and the grants part alone read the lease, whatever the
+	// controller announced; a module's consumer is created as the controller's EnsureConsumer creates it.
+	t.Run("the lease turns minting on only when handed away; a consumer is created as the controller's", func(t *testing.T) {
+		for _, row := range []struct {
+			name  string
+			raw   string
+			found bool
+			err   error
+			on    bool
+		}{
+			{"a controller holds it", `{"instance":"novox/1234/2026-10-27T20:00:00Z","epoch":57}`, true, nil, false},
+			{"handed away", `{"handed-to":"the operator's hand-over","handed-by":"person.jochen"}`, true, nil, true},
+			{"expired or deleted", ``, false, nil, false},
+			{"unreadable", ``, false, errors.New("refused"), false},
+			{"not a holder", `[1]`, true, nil, false},
+			{"both a controller and a handed holder", `{"instance":"novox/1","handed-to":"x"}`, true, nil, false},
+		} {
+			if on, why := LeaseHandedAway([]byte(row.raw), row.found, row.err); on != row.on || why == "" {
+				t.Errorf("%s: on %v (%s), want %v", row.name, on, why, row.on)
+			}
+			// The assigner's grants source follows it: the grants part's bucket only for a handed-away lease (issue 774).
+			on, _ := LeaseHandedAway([]byte(row.raw), row.found, row.err)
+			if bucket, _ := delivery.GrantSource(on); (bucket == delivery.PartGrantsBucket) != row.on {
+				t.Errorf("%s: the grants source is %s", row.name, bucket)
+			}
+		}
+		announced := map[string]announce.States{ControllerSeat: ControllerAnnouncement("novox")}
+		for reader, want := range map[string]bool{VaultSeat: true, GrantsModule: true, "mesh-delivery-assigner": true, "mesh-delivery-view": false} {
+			granted, _ := ReadsAnnouncedBy(reader, []string{ControllerLease}, announced)
+			if (len(granted) == 1) != want {
+				t.Errorf("%s reads the lease: %v, want %v", reader, granted, want)
+			}
+		}
+		c, _ := ConsumerFor(Principal{Kind: KindModule, Node: "a", Module: "m", Consumes: []string{"x.happened"}})
+		cfg := ConsumerConfig(c)
+		if cfg.Durable != "a_m" || cfg.AckPolicy != jetstream.AckExplicitPolicy || cfg.AckWait != 30*time.Second ||
+			cfg.MaxDeliver != 5 || cfg.DeliverPolicy != jetstream.DeliverNewPolicy || len(cfg.FilterSubjects) != 2 ||
+			cfg.Description == "" {
+			t.Errorf("a module's consumer is created as %+v", cfg)
+		}
+		// The grants part is granted the create of each account's consumer by its stream and name, and no other.
+		users, err := Users(Records{Nodes: []string{"a"}, Assigned: map[string][]Declared{"a": {
+			{Module: GrantsModule}, {Module: "m", Consumes: []string{"x.happened"}}, {Module: "quiet"}}}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, u := range users {
+			if u.Module != GrantsModule || u.Kind != KindModule {
+				continue
+			}
+			perms, err := PermissionsFor(u)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !MayPublish(perms, "$JS.API.CONSUMER.CREATE.EVENTS.a_m") || MayPublish(perms, "$JS.API.CONSUMER.CREATE.EVENTS.a_quiet") ||
+				MayPublish(perms, "$JS.API.CONSUMER.DELETE.EVENTS.a_m") || MayPublish(perms, "$JS.API.CONSUMER.CREATE.EVENTS.a_m.mesh.mod.x.event.happened") {
+				t.Errorf("the grants part creates consumers as %v", u.CreatesConsumers)
+			}
+		}
+		q := ConsumerConfig(QueueConsumer(Principal{Kind: KindProcess, Node: "a", Module: "m", Process: "p"},
+			QueueOwner{Process: "p", Stream: "M_WORK", MaxDeliver: 3}))
+		if q.Durable != "a_m_p" || q.FilterSubject != "" || q.MaxDeliver != 3 || q.DeliverPolicy != jetstream.DeliverAllPolicy {
+			t.Errorf("a process's queue consumer is created as %+v", q)
+		}
+	})
 }

go/buscompose/create.go

@@ -86,3 +86,30 @@ func ModuleStreamConfig(m ModuleStream) jetstream.StreamConfig {
 	}
 	return cfg
 }
+
+// ConsumerConfig is a pull consumer as the controller's EnsureConsumer creates it (mesh-controller internal/broker
+// JetStream.EnsureConsumer, a consumer not there yet): its durable name, explicit acks, its ack wait, max deliver and max
+// ack pending, its description, one filter or several, and from the stream's end when it is made FromNow. The grants part
+// creates a module's and a process's consumers with it from the lease write (novox/hq ADR 0561 §6): a create alone,
+// never an update of one the bus holds. A push consumer or a queue group is the controller's own and never made here.
+func ConsumerConfig(c Consumer) jetstream.ConsumerConfig {
+	cfg := jetstream.ConsumerConfig{
+		Durable:       c.Name,
+		AckPolicy:     jetstream.AckExplicitPolicy,
+		AckWait:       time.Duration(c.AckWaitSeconds) * time.Second,
+		MaxDeliver:    c.MaxDeliver,
+		MaxAckPending: c.MaxAckPending,
+		Description:   c.Why,
+	}
+	switch len(c.Filters) {
+	case 0:
+	case 1:
+		cfg.FilterSubject = c.Filters[0]
+	default:
+		cfg.FilterSubjects = c.Filters
+	}
+	if c.FromNow {
+		cfg.DeliverPolicy = jetstream.DeliverNewPolicy
+	}
+	return cfg
+}

go/buscompose/creates_streams_test.go

@@ -23,6 +23,8 @@ func TestTheGrantsPartCreatesOnlyDeclaredStreams(t *testing.T) {
 			{Module: GrantsModule, State: []Bucket{{Module: GrantsModule, Name: "assertions"}}, Reads: []string{VaultBusAccounts}},
 			{Module: RuntimeModule},
 		}},
+		// The node-engine's own manifest, placed on every node though no node is assigned it (novox/hq ADR 0563 §2, §3).
+		Engine: &Declared{Module: EngineModule, State: []Bucket{{Module: EngineModule, Name: EngineActsState}}},
 	}
 	users, err := Users(records)
 	if err != nil {
@@ -64,6 +66,15 @@ func TestTheGrantsPartCreatesOnlyDeclaredStreams(t *testing.T) {
 		{GrantsModule, "$JS.API.STREAM.CREATE.ASSIGNMENTS", false},
 		{GrantsModule, "$JS.API.STREAM.INFO.EVENTS", false},
 		{"mesh-delivery-builder", "$JS.API.STREAM.CREATE.KV_mesh-delivery-builder_steps", false},
+		// The node-engine's acts: created by the grants part, written by each node's engine under its own keys alone.
+		{GrantsModule, "$JS.API.STREAM.CREATE.KV_mesh-host_acts", true},
+		{"node.ace", "$JS.API.STREAM.CREATE.KV_mesh-host_acts", false},
+		{"node.ace", "$KV.mesh-host_acts.ace.act.hand-over-1", true},
+		{"node.ace", "$KV.mesh-host_acts.ace.open.hand-over.abc", true},
+		{"node.ace", "$KV.mesh-host_acts.novox.act.hand-over-1", false},
+		{"node.ace", "$JS.API.DIRECT.GET.KV_mesh-host_acts.$KV.mesh-host_acts.ace.ask.hand-over-1", true},
+		{"node.ace", "$JS.API.DIRECT.GET.KV_mesh-host_acts.$KV.mesh-host_acts.novox.ask.hand-over-1", false},
+		{"novox.node-tools", "$KV.mesh-host_acts.novox.act.hand-over-1", false},
 		// The sealed user list (ADR 0547 clause 7): the grants part writes its own bucket and no other.
 		{GrantsModule, "$JS.API.STREAM.CREATE.OBJ_mesh-grants-user-list", true},
 		{GrantsModule, "$O.mesh-grants-user-list.C.abc", true},

go/buscompose/derived.go

@@ -247,6 +247,30 @@ func ConsumersOf(users []Principal) []ModuleConsumer {
 	return out
 }
 
+// AccountConsumers are the durable consumers an account needs (novox/hq ADR 0561 §6): of ConsumersOf, each module's on
+// EVENTS and each process's on its own work queue, never one on a module stream it hears (those the controller makes with
+// the stream's grant). The grants part creates them from the lease write, with these configurations.
+func AccountConsumers(users []Principal) []ModuleConsumer {
+	queues := map[string]bool{}
+	for _, p := range users {
+		for _, q := range p.Queues {
+			queues[q.Stream] = true
+		}
+		for _, d := range p.Carries {
+			for _, q := range d.Queues {
+				queues[q.Stream] = true
+			}
+		}
+	}
+	var out []ModuleConsumer
+	for _, mc := range ConsumersOf(users) {
+		if mc.Consumer.Stream == consumerStream(Principal{Kind: KindModule}) || queues[mc.Consumer.Stream] {
+			out = append(out, mc)
+		}
+	}
+	return out
+}
+
 // HolderConsumerFor is the worker a seat's holders share on that seat's work queue.
 //
 // **One worker for every holder, and each holder pulls one ask when it is idle** (novox/hq ADR

go/buscompose/engine.go

@@ -0,0 +1,45 @@
+package buscompose
+
+import (
+	"git.novox.be/novox/mesh-sdk/go/asks"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+)
+
+// The node seat node-engine (novox/hq ADR 0563 §1): every node's engine holds it on its own bus account, and no module
+// claims it. Its verbs and events are the catalogue's (catalogue.EngineVerbs), read here rather than copied.
+
+// EngineSeat is the seat.
+const EngineSeat = catalogue.EngineSeat
+
+// EngineModule is the node-engine's manifest's module name, and EngineActsState its state the acts asked through the
+// node seat and its own asks are kept in (ADR 0563 §2, §3: "the engine's own state"): the bucket mesh-host_acts, keys
+// `<node>.act.<id>`, `<node>.open.<act>.<digest>` and `<node>.ask.<id>`, each written by that node's engine alone.
+const (
+	EngineModule    = "mesh-host"
+	EngineActsState = "acts"
+)
+
+// EngineActsBucket is that state's bucket.
+var EngineActsBucket = BucketName(EngineModule, EngineActsState)
+
+// engineGrants is what a node's engine is granted to hold its node seat and to ask the operator (ADR 0563 §1, §3): it
+// answers its own node's verbs (the caller-named subjects are added beside them with every principal's), says the
+// seat's events about its node, answers discovery for the seat, asks who answers what (the login shell's execute, ADR
+// 0563 §6), and asks the operator under asks.EngineAsker(node) on the router's seat as its holder declares it, as any
+// user of that seat is granted.
+func engineGrants(p Principal) (pub, sub []string) {
+	for _, v := range catalogue.EngineVerbs() {
+		sub = append(sub, "mesh.seat."+EngineSeat+".tool."+v.Name+"."+p.Node)
+	}
+	for _, e := range catalogue.EngineEvents {
+		pub = append(pub, "mesh.seat."+EngineSeat+".event."+e+"."+p.Node)
+	}
+	sub = append(sub, announcing(EngineSeat)...)
+	pub = append(pub, discovering()...)
+	tp, ts := seatTrafficGrants(SeatTrafficOf(asks.EngineAsker(p.Node), nil, p.Uses, nil))
+	// And its acts and asks, under its own node's keys alone; never the bucket's creation, which is the grants part's.
+	if own, err := NodeKeysGrants(EngineActsBucket, p.Node); err == nil {
+		pub = append(pub, own...)
+	}
+	return append(pub, tp...), append(sub, ts...)
+}

go/buscompose/nats.go

@@ -217,6 +217,11 @@ type Principal struct {
 	// ADR 0547 §2, ADR 0550 §5, issue 1126): its modules' own secrets sealed to its key, for the compositions it makes
 	// itself. Set while the vault's holder serves it.
 	AsksItsOwnSecrets bool
+	// AsksTheVaultToSign is a machine principal whose node-engine may ask the vault's `sign` in its own name, read the
+	// vault's public signing halves (`signers`) and the controller's lease key (novox/hq ADR 0550 §2): its own node's
+	// certificate, the keys it trusts, and the lease write that drops the controller's key. Set while the vault's holder
+	// serves `sign`.
+	AsksTheVaultToSign bool
 	// ServedReads are, for a machine principal, the keys of mesh-config's resolved values that other nodes' modules serve
 	// from (`<node>.<module>.<key>`, catalogue.ServedSettings): what every consumer is told, and so what a node composing
 	// its own modules reads of a provider elsewhere (issue 1126), each key alone. Sorted, none twice.
@@ -232,6 +237,10 @@ type Principal struct {
 	// 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
+	// CreatesConsumers are the durable consumers the grants part's principal alone may create beside the controller
+	// (novox/hq ADR 0561 §6): each placed module's on EVENTS and each process's on its work queue (AccountConsumers), by
+	// stream and name. Created only, never updated or deleted.
+	CreatesConsumers []ModuleConsumer
 
 	// 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
@@ -356,6 +365,10 @@ var VaultNodeKey = SeatVerb{Seat: "mesh-vault", Verb: "node-key"}
 // key (issue 1126, ADR 0550 §5); granted as Principal.AsksItsOwnSecrets says.
 var VaultOwn = SeatVerb{Seat: "mesh-vault", Verb: "own"}
 
+// VaultSign is the vault's verb a machine's node-engine asks in its own name for its own node's certificate (novox/hq
+// ADR 0550 §2); granted as Principal.AsksTheVaultToSign says.
+var VaultSign = SeatVerb{Seat: "mesh-vault", Verb: delivery.SignVerb}
+
 // VerbsTheControllerActsOnAWarrant are the other seat verbs the controller calls when the operator's warrant
 // chooses them (novox/hq ADR 0259): a machine's service restarted, and a walk started or stopped through the
 // controller's own `plans`, a machine's held builds sent by its own `push` and the builds held after a failed release
@@ -952,6 +965,18 @@ func PermissionsFor(p Principal) (Permissions, error) {
 			// on it rather than at the next unrelated change (ADR 0547 §2).
 			sub = append(sub, VaultSecretChanged)
 		}
+		// And, while the vault serves `sign`, its own node's certificate in its own name, the vault's public signing
+		// halves, read and watched, and the controller's lease key, read and watched, which says when the controller's key
+		// is no longer trusted (ADR 0550 §2). Read only.
+		if p.AsksTheVaultToSign {
+			pub = append(pub, VaultSignCall(p))
+			pub = append(pub, readGrants(delivery.SignersBucket, "")...)
+			pub = append(pub, readGrants(LeaseBucket, leaseKey)...)
+		}
+		// And its node seat, node-engine, and its asks to the operator in its own name (novox/hq ADR 0563 §1, §3).
+		ep, es := engineGrants(p)
+		pub = append(pub, ep...)
+		sub = append(sub, es...)
 		// 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 {
@@ -972,6 +997,8 @@ func PermissionsFor(p Principal) (Permissions, error) {
 			// 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 creating each durable consumer an account needs, by its stream and name (ADR 0561 §6).
+			pub = append(pub, CreateConsumerGrants(p.CreatesConsumers)...)
 			// And its own object bucket, where it writes the user list sealed to the bus node (ADR 0547 clause 7).
 			pub = append(pub, GrantsUserListWrites()...)
 		}
@@ -1659,6 +1686,21 @@ func CreateStreamGrants(streams []string) []string {
 	return out
 }
 
+// CreateConsumerGrants are the subjects that create each consumer by its stream and name, and read its info back: the
+// create of the client library's CreateConsumer for a consumer with no filter or several, never one filter's form (a
+// wildcard in a filter would widen the grant), an update or a delete.
+func CreateConsumerGrants(consumers []ModuleConsumer) []string {
+	var out []string
+	for _, mc := range consumers {
+		c := mc.Consumer
+		if !safeSubject.MatchString(c.Stream) || !safeSubject.MatchString(c.Name) || len(c.Filters) == 1 {
+			continue
+		}
+		out = append(out, "$JS.API.CONSUMER.CREATE."+c.Stream+"."+c.Name, "$JS.API.CONSUMER.INFO."+c.Stream+"."+c.Name)
+	}
+	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"
@@ -1827,6 +1869,11 @@ func VaultOwnCall(p Principal) string {
 	return "mesh.seat." + VaultOwn.Seat + "." + CallKind + "." + VaultOwn.Verb + "." + CallerToken(p.Username())
 }
 
+// VaultSignCall is the subject a machine principal's node-engine asks the vault's `sign` on, in its own name.
+func VaultSignCall(p Principal) string {
+	return "mesh.seat." + VaultSign.Seat + "." + CallKind + "." + VaultSign.Verb + "." + CallerToken(p.Username())
+}
+
 // VaultSecretChanged is the vault's event that a secret changed (a name and its generation, never a value), which a
 // node composing its own hears to compose again (issue 1126, ADR 0547 §2).
 var VaultSecretChanged = "mesh.mod." + VaultOwn.Seat + ".event.secret-changed"

go/buscompose/testdata/controller-credentials.json

@@ -0,0 +1,21 @@
+{
+ "how": "Written by mesh-controller 0fbb5ef's own issueWith, sealProvisionerClient and heldProcessAccount (cmd/mesh-controller), run unchanged in a scratch integration test against a local store with the default seats seeded, on 2026-10-27 (issue 774): each row is the exact value the controller handed the vault. Never edit a row by hand: capture it again.",
+ "rows": [
+  {
+   "name": "module",
+   "held": "{\"url\":\"nats://10.0.0.1:4222\",\"fingerprint\":\"ab:cd\",\"node\":\"laptop\",\"module\":\"cap-bot\",\"user\":\"laptop.cap-bot\",\"password\":\"pw-module\",\"claims\":[{\"seat\":\"mesh-vault\",\"scope\":\"mesh\",\"serves\":[\"get\",\"accept\",\"secret-ask\",\"issued\",\"rotate\",\"move-in\",\"node-key\",\"own\",\"move-asks\"]},{\"seat\":\"node-service-manager\",\"scope\":\"node\",\"serves\":[\"status\"]},{\"seat\":\"mesh-controller\",\"scope\":\"mesh\",\"serves\":[\"tools\",\"calls\",\"status\",\"nodes\",\"node\",\"placement-export\",\"modules\",\"seats\",\"builds\",\"plans\",\"delivery-plan\",\"delivery-order\",\"delivery-check\",\"deliver\",\"delivery-stop\",\"delivery-backups-again\",\"delivery-walks\",\"plan\",\"assign\",\"unassign\",\"pin\",\"unpin\",\"push\",\"rotate\",\"give\",\"issued\",\"secret-move\",\"secret-ask\",\"issue\",\"token\",\"settings\",\"command\",\"queue\",\"cancel\",\"clear\",\"replay\",\"try\",\"kill\",\"pause\",\"resume\",\"hand-act\",\"drill\",\"warranted\",\"hand-acts\",\"durations\",\"conditions\",\"healers\",\"doctor\",\"upgrade\",\"bus\",\"retire\",\"cleanup\",\"judge-directories\",\"root-free\",\"dead-letters\",\"data\",\"build\",\"artifacts\",\"held\",\"collect\",\"move-placement\",\"move-config\",\"mirrors\",\"images\"]},{\"seat\":\"no-such-seat\",\"scope\":\"node\"}]}"
+  },
+  {
+   "name": "module-no-claims-no-fingerprint",
+   "held": "{\"url\":\"nats://10.0.0.1:4222\",\"node\":\"laptop\",\"module\":\"cap-plain\",\"user\":\"laptop.cap-plain\",\"password\":\"pw-plain\"}"
+  },
+  {
+   "name": "provisioner",
+   "held": "{\"url\":\"nats://10.0.0.1:4222\",\"fingerprint\":\"ab:cd\",\"node\":\"laptop\",\"user\":\"provisioner.laptop\",\"password\":\"pw-prov\"}"
+  },
+  {
+   "name": "process",
+   "held": "{\"url\":\"nats://10.0.0.1:4222\",\"fingerprint\":\"ab:cd\",\"node\":\"laptop\",\"module\":\"mesh-mail\",\"user\":\"laptop.mesh-mail.send\",\"password\":\"pw-proc\"}"
+  }
+ ]
+}

go/buscompose/userlist_switch.go

@@ -77,8 +77,12 @@ func grantsOwnObjects(p Principal, pattern string) bool {
 // 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}}
+// NamedReaders are the states only the modules named may read, by `<owner>.<name>`: the grants part's wanted accounts
+// are read by the vault alone (novox/hq ADR 0561 §2).
+// The controller's lease is read by the parts that turn on at its write (ADR 0561 §3, §6), and by the assigner, which
+// reads the catalogue's placement alone from then (ADR 0549 §5, issue 774).
+var NamedReaders = map[string][]string{VaultBusAccounts: {GrantsModule}, GrantsAccounts: {VaultSeat},
+	ControllerLease: {VaultSeat, GrantsModule, delivery.AssignerModule}}
 
 // ReaderMay says whether module may read the state read (`<owner>.<name>`) by the named readers: always, for a state
 // that names none.

go/buscompose/users.go

@@ -134,6 +134,11 @@ type Records struct {
 	// account agents run as, judged unable to become root by its node-engine, and serves no login shell
 	// execute. A machine absent is not free: no record of a pass is no pass.
 	RootFree map[string]bool
+	// Engine is the node-engine's own declaration, from its manifest (EngineModule): placed on every node though no node is
+	// assigned it, since every node runs it (novox/hq ADR 0563 §2, §3). Its state, logs and streams are created by the
+	// grants part as a placed module's are; it adds no principal, since each node's engine speaks as the node's account.
+	// Nil where its manifest was not read.
+	Engine *Declared
 	// Announced is each module's last announcement of the states it keeps (novox/hq ADR 0495, issue 1790), as the
 	// controller keeps it; a module absent has announced nothing yet. Nil where none was read.
 	Announced map[string]announce.States
@@ -149,6 +154,7 @@ func Users(r Records) ([]Principal, error) {
 		AsksTheConfig: servedOf(r, VerbsTheControllerAsksTheConfig), FilesFor: sortedCopy(r.Nodes)}}
 
 	served := servedReadsOf(r)
+	grants := -1
 	for _, node := range sortedCopy(r.Nodes) {
 		witness := false
 		var checks []string
@@ -164,7 +170,7 @@ func Users(r Records) ([]Principal, error) {
 		}
 		out = append(out, Principal{Kind: KindNode, Node: node, WitnessesController: witness, Checks: checks,
 			MovesIntoTheVault: servesMoveIn(r), StatesItsKeyToTheVault: servesVerb(r, VaultNodeKey),
-			AsksItsOwnSecrets:     servesVerb(r, VaultOwn),
+			AsksItsOwnSecrets: servesVerb(r, VaultOwn), AsksTheVaultToSign: servesVerb(r, VaultSign), Uses: asksSeatOf(r),
 			FollowsGrantsUserList: bus, ServedReads: servedOn(served, node)})
 		// **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.
@@ -225,6 +231,7 @@ func Users(r Records) ([]Principal, error) {
 			// 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)
+				grants = len(out) - 1
 			}
 			// **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.
@@ -258,6 +265,11 @@ func Users(r Records) ([]Principal, error) {
 		out = append(out, p)
 	}
 
+	// The grants part creates the durable consumers the accounts need (novox/hq ADR 0561 §6), by stream and name.
+	if grants >= 0 {
+		out[grants].CreatesConsumers = AccountConsumers(out)
+	}
+
 	// Refused here rather than discovered by the server. Two users with one name is a file the
 	// server reads as one of them, and which one depends on the order — so a module assigned to a
 	// node twice, or a person named after nothing, is a composition that must not be written.
@@ -444,7 +456,15 @@ func runnerServes(d Declared) bool {
 // name. What the grants part may create, and nothing beside.
 func declaredStreamsOf(r Records) []string {
 	seen := map[string]bool{}
+	placed := [][]Declared{}
 	for _, mods := range r.Assigned {
+		placed = append(placed, mods)
+	}
+	// The node-engine's manifest is placed on every node (ADR 0563): its declared state is created as a placed module's.
+	if r.Engine != nil {
+		placed = append(placed, []Declared{*r.Engine})
+	}
+	for _, mods := range placed {
 		for _, d := range mods {
 			for _, b := range d.State {
 				seen["KV_"+b.Bucket()] = true

go/buscompose/writers.go

@@ -245,6 +245,11 @@ var WritersTable = []WriterRow{
 	{State: "a machine's have", Writer: "the node-engine of the machine, under its own keys `<node>.>`",
 		KeptIn: "key-value " + delivery.HaveBucket + ", twenty revisions of each key",
 		Others: "read through `reads` as node-engine.have", Subjects: kvOf(delivery.HaveBucket), Writes: ownNodeKeys},
+	// The acts a node's engine was asked through its node seat, and its own asks (novox/hq ADR 0563 §2, §3): the
+	// node-engine's declared state, created by the grants part, written by each node's engine under its own keys.
+	{State: "a machine's hand acts", Writer: "the node-engine of the machine, under its own keys `<node>.>`, compare-and-set",
+		KeptIn: "key-value " + EngineActsBucket + ", the node-engine's declared state acts",
+		Others: "read through the node seat's verb acts", Subjects: kvOf(EngineActsBucket), Writes: ownNodeKeys},
 	// The contents of a declaration's files over 64 KiB (novox/hq ADR 0486 §2): the controller alone writes the bucket, each
 	// object under the digest of its content; a node-engine reads one by its name, with no list and no write.
 	{State: "a declaration's large files", Writer: "controller, each object under the sha256 digest of its content; the " +

go/caller_test.go

@@ -75,6 +75,21 @@ func TestACallerInTheArgumentsIsNeverTheCaller(t *testing.T) {
 	if got != "shanks.node-tools" {
 		t.Fatalf("with a caller in the arguments the tool read %q, want the runtime's", got)
 	}
+	// A module's trusted list of callers (issue 774, ADR 0563 §8) grants the callers it names as the runtime proved them:
+	// a module on any machine, <machine>.<module> exactly, person.<name> exactly; no wildcard, never one unproven.
+	callers, err := ParseCallers([]byte(`{"callers":["node-tools","ace.claude-code","person.jo","*"]}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for caller, want := range map[string]bool{"shanks.node-tools": true, "ace.claude-code": true, "g14.claude-code": false,
+		"person.jo": true, "person.node-tools": false, Unproven: false, "": false, "novox.mesh-vault": false} {
+		if callers.Allows(caller) != want {
+			t.Errorf("%q allowed: %v, want %v", caller, !want, want)
+		}
+	}
+	if _, err := ParseCallers([]byte(`{"callers":["x"],"more":1}`)); err == nil {
+		t.Error("a list with a field it does not know was read")
+	}
 }
 
 // A runtime that names no caller — one from before issue 365, or a call on the subject that names none — is

go/callers.go

@@ -0,0 +1,48 @@
+package stdio
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+// Callers is a module's trusted list of who may call a verb of its (novox/hq ADR 0459 §2, ADR 0563 §8), as the mesh
+// writes a list setting into a file the module reads: `{"callers": [...]}`. An entry is a module's name (that module on
+// any machine), exactly <machine>.<module>, or exactly person.<name>. Each caller is the runtime's proof (CallerOf), never
+// an argument; nobody beyond the list is granted, a wildcard is no entry, and an unproven caller never matches.
+type Callers []string
+
+// ParseCallers reads a callers file: the list under `callers`, and nothing else.
+func ParseCallers(raw []byte) (Callers, error) {
+	var f struct {
+		Callers Callers `json:"callers"`
+	}
+	dec := json.NewDecoder(bytes.NewReader(raw))
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&f); err != nil {
+		return nil, fmt.Errorf("the callers setting is not a list of callers: %v", err)
+	}
+	return f.Callers, nil
+}
+
+// Allows says whether caller, as the runtime proved it, is one the list names.
+func (c Callers) Allows(caller string) bool {
+	if caller == "" || caller == Unproven {
+		return false
+	}
+	for _, entry := range c {
+		if entry == "" || strings.ContainsAny(entry, "*> ") {
+			continue
+		}
+		if entry == caller {
+			return true
+		}
+		if !strings.Contains(entry, ".") {
+			if _, module, ok := strings.Cut(caller, "."); ok && module == entry && !strings.HasPrefix(caller, "person.") {
+				return true
+			}
+		}
+	}
+	return false
+}

go/catalogue/build.go

@@ -126,23 +126,7 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
 				continue
 			}
 			made := by[a.Name]
-			// What the runtime loads: what the artifact said, else every entrypoint of a module
-			// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
-			//
-			// **Never, unasked, a bundle one of the module's own resources runs** (novox/hq issue 213).
-			// A process the host runs is the module's service, not its tools: the controller declares
-			// the verbs it answers as `tools` and serves them itself, and its bundle would otherwise
-			// have been launched a second time by the node's runtime, as an MCP child it is not.
-			loads := append([]string(nil), a.Loads...)
-			if a.Loads == nil && len(m.Tools) > 0 && !run[a.Name] {
-				loads = append([]string(nil), a.Entrypoints...)
-				// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
-				// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
-				// as Go — the runtime execs it — exactly as a TypeScript one is through its launcher.
-				if bin := BinaryOf(a); bin != "" {
-					loads = []string{bin}
-				}
-			}
+			loads := BundleLoads(m, a, run)
 			// **Kept, never routed** (ADR 0155): the builder publishes to the store at the address
 			// it reached it by, and a manifest carrying that address names an installation —
 			// registration refused node-tools for exactly this on 2026-10-02. The build record
@@ -715,3 +699,31 @@ func undeliveredBundles(m Manifest) []string {
 	}
 	return problems
 }
+
+// BundleLoads is what the runtime loads of the bundle artifact a of m (run: the bundles one of m's own resources runs,
+// runByAResource): what the artifact said, else every entrypoint of a module that declares tools, else nothing; a
+// bundle compiled to a binary is served by its binary. The rule a build's resolution keeps on Bundle.Loads, and what a
+// module composed as what runs of it reads again when the runtime already dropped it (issue 1126).
+func BundleLoads(m Manifest, a Artifact, run map[string]bool) []string {
+	// What the runtime loads: what the artifact said, else every entrypoint of a module
+	// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
+	//
+	// **Never, unasked, a bundle one of the module's own resources runs** (novox/hq issue 213).
+	// A process the host runs is the module's service, not its tools: the controller declares
+	// the verbs it answers as `tools` and serves them itself, and its bundle would otherwise
+	// have been launched a second time by the node's runtime, as an MCP child it is not.
+	loads := append([]string(nil), a.Loads...)
+	if a.Loads == nil && len(m.Tools) > 0 && !run[a.Name] {
+		loads = append([]string(nil), a.Entrypoints...)
+		// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
+		// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
+		// as Go — the runtime execs it — exactly as a TypeScript one is through its launcher.
+		if bin := BinaryOf(a); bin != "" {
+			loads = []string{bin}
+		}
+	}
+	return loads
+}
+
+// RunByAResource is the bundles of m one of its own resources runs (its service, not its tools).
+func RunByAResource(m Manifest) map[string]bool { return runByAResource(m) }

go/catalogue/checker_seat.go

@@ -0,0 +1,37 @@
+package catalogue
+
+// The delivery's checker (novox/hq ADR 0547 §10, issue 774): one holder for the mesh, the module
+// mesh-delivery-checker, which judges a pull request's head and a pushed head the same way. The try the
+// controller forwarded to it is a verb of this seat, answered by the checker with the verdict it gives a pull
+// request, so the try outlives the controller.
+
+// CheckerSeat is the seat mesh-delivery-checker holds.
+const CheckerSeat = "mesh-delivery-checker"
+
+// checkerVerbs are the checker seat's verbs: ask a try, read one, end one by hand. Optional until the checker serves them
+// everywhere.
+func checkerVerbs() []Verb {
+	return []Verb{
+		{Name: "try", Optional: true, Description: "Try a pushed head before its pull request is opened: the checker " +
+			"judges it as it judges a pull request's head, merged onto its trunk's head, its unit and integration " +
+			"levels through the build modules, and owes the forge nothing. Answers the try's id at once; try-read " +
+			"reads where it stands. A try of the same head that waits or runs is the answer to a second ask; at most " +
+			"4 wait or run at once, mesh-wide.",
+			Input: schema(map[string]string{"repository": "<owner>/<name>",
+				"head":  "the full commit to try, 40 or 64 hex digits",
+				"trunk": "the trunk commit to merge it onto, or the trunk's branch for its head now; the trunk's head when absent",
+				"tests": "a go test -run pattern: only those tests run, and nothing is kept",
+				"level": "unit or integration: only this level; both when absent"},
+				[]string{"repository", "head"}),
+			Replaces: []string{"sh merge-check.sh", "docker run postgres"}},
+		{Name: "try-read", Optional: true, Description: "Where a try stands, as stored: queued, running, or its end " +
+			"(pass, fail, or error when it could not run), with what was said of it, the head and the trunk commit " +
+			"it was merged onto, the time it took and what failed first. Read-only.",
+			Input: schema(map[string]string{"id": "the try's id, try-<digits>"}, []string{"id"})},
+		{Name: "try-end", Optional: true, Description: "End a try that waits or runs, as error, by hand: say why (kept in " +
+			"what it says). Its place among the tries is free at once and the next try of its head asks anew with a new " +
+			"id. A try that ended already is refused.",
+			Input: schema(map[string]string{"id": "the try's id, try-<digits>", "why": "why it is ended, in words"},
+				[]string{"id", "why"})},
+	}
+}

go/catalogue/declaration.go

@@ -1103,6 +1103,9 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 		}
 		for _, unsettled := range resources {
 			if pr, ok := unsettled[HandedProvisionField].(PlanProvision); ok {
+				if handing == nil && m.Stubbed {
+					continue // held: its credential file is what runs of it, left out (issue 1126)
+				}
 				if handing == nil {
 					return nil, fmt.Errorf("%s: its credential of %s is handed to the provisioner and the module is "+
 						"not: nothing would fill it", m.Module, pr.Provision)
@@ -1127,6 +1130,9 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 				continue
 			}
 			if unsettled[HandedSecretField] != nil {
+				if handing == nil && m.Stubbed {
+					continue // held: its own secret's file is what runs of it, left out (issue 1126)
+				}
 				if handing == nil {
 					return nil, fmt.Errorf("%s: its own secret %v is handed to the provisioner and the module is "+
 						"not: nothing would fill it", m.Module, unsettled[HandedSecretField])

go/catalogue/engine_seat.go

@@ -0,0 +1,57 @@
+package catalogue
+
+// The node seat node-engine (novox/hq ADR 0563 §1): held on every node by that node's engine (mesh-host), which serves
+// its verbs on its own bus account. No module claims it and no assignment holds it: what the mesh knows of its holder
+// is the node's record and the engine's haves (ADR 0563 §1 changes ADR 0110 §6 and §7 for this one seat).
+//
+// Its verbs carry no signature (§7): the runtime proves the caller, which matters only for the record. The read-only
+// ones change nothing or are bounded in the engine's own state (§2); hand-over and access-act perform nothing on the
+// call, and act only on the operator's warrant to the engine's own ask (§3).
+
+// EngineSeat is the node seat every node's engine holds.
+const EngineSeat = "node-engine"
+
+// EngineVerbs are the node-engine seat's verbs, in the order ADR 0563 §1 names them.
+func EngineVerbs() []Verb {
+	return []Verb{
+		{Name: "hand-over", Description: "Hand a directory this machine uses as found to the mesh (novox/hq ADR 0563 §3, " +
+			"§5): the engine judges the path as it does every hand-over (absolute, as it states it, used as found, " +
+			"reached through no link) and refuses in words, or asks the operator on their channel at the level approve, " +
+			"binding the owner, group and mode it will set. Nothing changes on the call: only the operator's yes hands " +
+			"it over. One ask is open per path; acts shows where it stands.",
+			Input: schema(map[string]string{"path": "the directory's absolute path, as the engine states it",
+				"why": "why it is asked, in words the operator reads"}, []string{"path"})},
+		{Name: "access-act", Description: "Ask the operator for the take act on a library whose root holds data outside its " +
+			"group (novox/hq ADR 0328 §7, ADR 0563 §3, §4), on the library's home engine: the access as declared and its " +
+			"root as last declared, judged and refused in words or asked at the level approve. Only the operator's yes " +
+			"sets the library's group, group write and setgid under its root. One ask is open per access.",
+			Input: schema(map[string]string{"act": "the act: take", "access": "the access, library:<name>",
+				"why": "why it is asked, in words the operator reads"}, []string{"act", "access"})},
+		{Name: "judge-directories", Description: "Which of this machine's declared directories the engine would refuse to " +
+			"make or keep, one line each (novox/hq ADR 0563 §2). Read-only: changes no owner or mode.",
+			Input: schema(map[string]string{}, nil)},
+		{Name: "setuid-search", Description: "Throw away the engine's last search for setuid programs and start a full one " +
+			"(novox/hq ADR 0563 §2); until it completes root-free answers that the machine is not judged yet. Refused while " +
+			"one runs, and when one was started within the hour, naming when the next may start.",
+			Input: schema(map[string]string{"why": "why it is asked, in words"}, nil)},
+		{Name: "root-free", Description: "Whether this machine is root-free (novox/hq ADR 0259 §8, ADR 0563 §6): free only " +
+			"on the engine's own verdict, at most fifteen minutes old, that the account agents run as cannot become root " +
+			"without a person, and the login shell's execute not served here. Anything else is no pass, and says why. " +
+			"Answered by this machine's engine alone.",
+			Input: schema(map[string]string{}, nil)},
+		{Name: "acts", Description: "Every act this machine's engine was asked through this seat (novox/hq ADR 0563 §9): " +
+			"each hand-over, access act and setuid search, open, done or refused, with who asked, the ask and the " +
+			"operator's warrant. Read-only.",
+			Input: schema(map[string]string{"limit": "at most this many, newest", "id": "one act, by its id"}, nil)},
+	}
+}
+
+// EngineEvents are what the seat says of an act, each naming the act, the path or access, the caller as the runtime
+// proved it and the ask (ADR 0563 §1).
+var EngineEvents = []string{"asked", "done", "refused"}
+
+// engineSeat is the seat's row in the closed set.
+func engineSeat() Seat {
+	return Seat{Name: EngineSeat, Scope: ScopeNode, Serves: EngineVerbs(), Emits: append([]string(nil), EngineEvents...),
+		HeldByTheEngine: true, Decision: "novox/hq ADR 0563"}
+}

go/catalogue/handed_secrets_test.go

@@ -185,6 +185,22 @@ func TestAHandedModulesCredentialIssuedForItIsNamedInItsPlanAndNoValueIsSealed(t
 	if !reflect.DeepEqual(c.Plans["bot"].Provisions, want) {
 		t.Fatalf("the plan names %+v, want %+v", c.Plans["bot"].Provisions, want)
 	}
+	// Issue 1126 (novox's seed: "gitea: its credential of postgres-database is handed to the provisioner and the module
+	// is not"): held, the module is composed as its stub, with no template and no item, so nothing is handed. Its
+	// credential and its own secret are what runs of it, left out, and the composition is not refused.
+	r := forgeReader(t, true, true)
+	for i := range r.Modules {
+		if r.Modules[i].Module == "bot" {
+			h := *r.Modules[i].Handed
+			h.Templates = nil
+			r.Modules[i].Handed, r.Modules[i].Stubbed, r.Modules[i].Build = &h, true, nil
+			r.Modules[i].Resources = slices.DeleteFunc(r.Modules[i].Resources, func(x map[string]any) bool { return x["type"] != "directory" })
+		}
+	}
+	c, got = composeWith(t, r, handingTo("store:5000"))
+	if strings.Contains(got, SecretID("forge-read")) || strings.Contains(got, NeedID("token")) || c.Plans["bot"].Provisions != nil {
+		t.Fatalf("a held module's handed credential or own secret is composed: %s", got)
+	}
 }
 
 func TestACredentialIssuedForAHolderIsSealedAsBeforeWhereItsModuleIsNotHanded(t *testing.T) {

go/catalogue/manifest.go

@@ -870,6 +870,11 @@ type Manifest struct {
 	// path its manifest leaves to the mesh, a binding). Nil for any other module. Never in a manifest's JSON.
 	OwnsPaths []string `json:"-"`
 
+	// Stubbed marks a module composed as its stub (compose.Stub: held on its node, issue 1126): none of its own
+	// composition is applied, so what it hands the provisioner (a credential the vault keeps for it, its own secrets)
+	// is left out of its plan as it runs, never refused for want of a plan. Never in a manifest's JSON.
+	Stubbed bool `json:"-"`
+
 	// Jails are the fail2ban jails this module declares for its own service (novox/hq to-be 31).
 	// Written into whichever node runs the module, the same way `listens` become that node's rules.
 	Jails []Jail `json:"jails,omitempty"`

go/catalogue/seats.go

@@ -67,6 +67,10 @@ type Seat struct {
 	// names paths. Compiled, never stored, like Receives: adding or taking away a path is a decision,
 	// recorded, and the store's rows carry no column for it.
 	Paths []SeatPath
+	// HeldByTheEngine says the seat is held on every node by that node's engine, which serves its verbs on its own bus
+	// account (novox/hq ADR 0563 §1): no module claims it and no assignment holds it. Compiled, never stored, like
+	// Receives.
+	HeldByTheEngine bool
 	// Decision is the record that made it a seat.
 	Decision string
 }
@@ -171,7 +175,8 @@ var defaultSeats = append([]Seat{
 					"origin": "issued for a bus account the controller minted for a core or moved module and hands " +
 						"at once (ADR 0374, issue 787); left out for a value given at the terminal"}), nil)},
 			{Name: "secret-ask", Optional: true, Description: "Ask the operator for a module's own secret at a desk, " +
-				"from the controller alone: the ask is recorded in the vault's store and bounded before the prompt " +
+				"from the controller or a caller the vault's manifest names, named as the bus proved it (novox/hq ADR " +
+				"0563 §8): the ask is recorded in the vault's store and bounded before the prompt " +
 				"opens, and what is typed is sealed to a key the vault made for the call and opens there alone.",
 				Input: schema(vaultIntake(map[string]string{"node": "the machine the secret is for",
 					"module": "the module", "name": "the secret's name in the module",
@@ -224,6 +229,18 @@ var defaultSeats = append([]Seat{
 				Input: map[string]any{"type": "object", "properties": map[string]any{"asks": map[string]any{
 					"type": "array", "items": map[string]any{"type": "object"},
 					"description": "the controller's rows: id, node, module, name, desk, asked_by, opened_at, ended_at, outcome"}}}},
+			{Name: "issue-account", Optional: true, Description: "Mint one bus account the grants part wants, now (novox/hq " +
+				"ADR 0561 §9): only while the controller's lease is handed away, never a node's account or the " +
+				"controller's, never anew for one the vault holds a value or an adopted hash for. Never the value.",
+				Input: schema(map[string]string{"user": "the bus user, e.g. ace.mesh-build-go"}, []string{"user"})},
+			{Name: "sign", Optional: true, Description: "Sign with the vault's key or authority (novox/hq ADR 0550 §2): " +
+				"kind node-certificate signs the certificate of the calling machine's internal name for the serving key " +
+				"its record states, built from bus state alone and asked by that machine's node-engine only; kind " +
+				"enrolment signs an enrolment reply under its own context, for a caller the adoption record names. " +
+				"Answers the certificate or the signature and the signer's fingerprint, and says signed; never a key.",
+				Input: schema(map[string]string{"kind": "node-certificate or enrolment",
+					"node":  "the machine, for a node certificate: the caller's own",
+					"reply": "the enrolment reply's bytes in base64, for an enrolment"}, []string{"kind"})},
 		}},
 	// The owner of every config value (novox/hq ADR 0348 §9, design 57 K3): its holder alone writes the buckets
 	// mesh-config_values, _resolved, _predefined and _proposals, and serves the one verb `config` (§1, §10).
@@ -261,6 +278,8 @@ var defaultSeats = append([]Seat{
 	// Placement (novox/hq ADR 0567): which module runs on which node, state on the bus held by the assigner, changed only by
 	// a proposal the nodes answer and the operator approves. Its states and events are the holder module's.
 	{Name: PlacementSeat, Scope: ScopeMesh, Serves: placementVerbs(), Decision: "novox/hq ADR 0567"},
+	// The delivery's checker (novox/hq ADR 0547 §10, issue 774): the try is its verb, not the controller's.
+	{Name: CheckerSeat, Scope: ScopeMesh, Serves: checkerVerbs(), Decision: "novox/hq ADR 0547"},
 	// Deferred renames (novox/hq ADR 0121): these deliver a provision, so renaming them is a
 	// delivering-seat migration with a mesh-wide cascade if a holder stops resolving mid-flight.
 	// They keep their names until that migration is done deliberately, apart from the node-* pass.
@@ -442,6 +461,8 @@ var defaultSeats = append([]Seat{
 	// A node's files, read and managed (novox/hq ADR 0394, files.go): beside node-reads until mesh-files is assigned
 	// on every node, then node-reads goes (ADR 0394 §9).
 	{Name: FilesSeat, Scope: ScopeNode, Decision: "novox/hq ADR 0394", Serves: filesVerbs()},
+	// The node's engine's own verbs and asks (novox/hq ADR 0563 §1): held by the engine on every node, by no module.
+	engineSeat(),
 },
 	// The graphical session's roles (novox/hq ADR 0208), last because they are a workstation's.
 	graphicalSessionSeats()...)
@@ -515,7 +536,8 @@ 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.Yields = d.Yields                   // never stored (ADR 0553)
+			row.HeldByTheEngine = d.HeldByTheEngine // never stored (ADR 0563)
 			row.Serves = optionalAsCompiled(row.Serves, d.Serves)
 		}
 		merged = append(merged, row)
@@ -628,6 +650,13 @@ func claimProblems(m Manifest) []string {
 	}
 
 	for _, c := range m.Claims {
+		if s, known := SeatNamed(c.Name); known && s.HeldByTheEngine {
+			// The node's engine holds it on every node, and no module may (novox/hq ADR 0563 §1): a module answering
+			// root-free or a hand-over would be an agent answering it.
+			problems = append(problems, fmt.Sprintf("%s claims %s, which every node's engine holds itself and no "+
+				"module may (novox/hq ADR 0563 §1)", m.Module, c.Name))
+			continue
+		}
 		if _, known := SeatNamed(c.Name); known {
 			// **A seat's scope and what it delivers are not judged here** (novox/hq ADR 0122).
 			// This function runs wherever a manifest is parsed, and one of those places is the

go/catalogue/seats_test.go

@@ -49,6 +49,43 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 		[]string{"placement", "proposals", "propose", "withdraw", "again", "adopt", "hand-back"}) {
 		t.Errorf("the placement seat is %v, %v", ok, s)
 	}
+	// The checker's seat serves the try, which replaces the shell's merge check (ADR 0547 §10, ADR 0245).
+	var checkerVerbs []string
+	for _, s := range Seats() {
+		if s.Name == CheckerSeat {
+			for _, v := range s.Serves {
+				checkerVerbs = append(checkerVerbs, v.Name)
+				if v.Name == "try" && strings.Join(v.Replaces, "|") != "sh merge-check.sh|docker run postgres" {
+					t.Errorf("try replaces %v", v.Replaces)
+				}
+			}
+		}
+	}
+	if strings.Join(checkerVerbs, ",") != "try,try-read,try-end" {
+		t.Errorf("the checker seat serves %v", checkerVerbs)
+	}
+	// The node seat node-engine is the node's engine's (novox/hq ADR 0563 §1): at node scope, delivering nothing, its six
+	// verbs and three events, held by no assignment, and a module's claim of it refused.
+	if engine, ok := SeatNamed(EngineSeat); !ok || engine.Scope != ScopeNode || engine.Delivers != "" || !engine.HeldByTheEngine {
+		t.Errorf("node-engine is %+v, not a node seat delivering nothing that the engine holds", engine)
+	} else {
+		var verbs []string
+		for _, v := range engine.Serves {
+			verbs = append(verbs, v.Name)
+		}
+		// acts reads one act by its id too (ADR 0563 §9: the seat's tools are its command line).
+		if props, _ := engine.Serves[len(engine.Serves)-1].Input["properties"].(map[string]any); props["id"] == nil {
+			t.Errorf("acts takes no id: %v", engine.Serves[len(engine.Serves)-1].Input)
+		}
+		if strings.Join(verbs, ",") != "hand-over,access-act,judge-directories,setuid-search,root-free,acts" ||
+			strings.Join(engine.Emits, ",") != "asked,done,refused" {
+			t.Errorf("node-engine serves %v and emits %v", verbs, engine.Emits)
+		}
+	}
+	if _, err := ParseManifest([]byte(`{"module":"thing","version":"1","claims":[{"name":"node-engine","scope":"node"}]}`)); err == nil ||
+		!strings.Contains(err.Error(), "node-engine") {
+		t.Errorf("a module's claim of node-engine was not refused: %v", err)
+	}
 	// Forty-six with the three build seats replacing node-build-agent and the retired mesh-build-machine (novox/hq
 	// ADR 0525 §2, §10); forty-five with node-files (novox/hq ADR 0394); forty-four again once node-reads goes.
 	// Forty-four with node-provisioner (novox/hq ADR 0349 clause 3); forty-three with mesh-provisioner (novox/hq ADR 0349 clause 3); forty-two with mesh-config (novox/hq ADR 0348 §9); forty-one with node-reads (novox/hq ADR 0310); forty with node-nfs-server and node-mounts (novox/hq ADR 0263); thirty-eight with node-resolver (novox/hq ADR 0247); thirty-seven with mesh-delivery (novox/hq ADR 0239); thirty-six since node-resolver-config retired
@@ -62,8 +99,9 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 	// node-container-runtime (ADR 0207); nineteen with node-environment and node-login-shell (ADR 0203,
 	// ADR 0204); seventeen with node-build-agent (ADR 0190). One fewer once the retired
 	// mesh-build-machine row goes, when no registered manifest claims it.
-	if len(Seats()) != 47 {
-		t.Errorf("the mesh defines %d seats rather than 47; the set is closed, so a change here is "+
+	// Forty-eight with mesh-delivery-checker (novox/hq ADR 0547 §10, issue 774); forty-nine with node-engine (novox/hq ADR 0563 §1).
+	if len(Seats()) != 49 {
+		t.Errorf("the mesh defines %d seats rather than 49; the set is closed, so a change here is "+
 			"a decision (novox/hq ADR 0110): %s", len(Seats()), seatNames())
 	}
 }

go/compose/composed.go

@@ -130,6 +130,22 @@ func compositions(in Input, node string, fps map[string]string, mode Mode, appli
 			n.Kept = kept
 		}
 	}
+	// A module composed as what runs of it contributes to the runtime what the runtime serves of it as it runs
+	// (Node.RunsTools); one of its own account is served by a runtime of its own, from its manifest as before.
+	for i := range reading.Nodes {
+		n := &reading.Nodes[i]
+		if n.Name != node || n.RunsTools == nil {
+			continue
+		}
+		kept := make(map[string]catalogue.Manifest, len(n.Kept))
+		for m, man := range n.Kept {
+			if man.Stubbed && man.RunsAs == "" {
+				man.Bundles = runningBundles(n.RunsTools[m], reading.Catalogue[m])
+			}
+			kept[m] = man
+		}
+		n.Kept = kept
+	}
 	isCarried := func(module, id string) bool {
 		if module == "" {
 			module, _ = declaration.ModuleGuess(id)
@@ -293,6 +309,106 @@ func RunsAnyOf(runs *delivery.Composed, module string) bool {
 	return false
 }
 
+// ToolsRunning is, by module, the tools bundles that run on the node (Node.RunsTools): each bundle archive a module's
+// resource unpacks at its BundlePath, with what the runtime's own process loads of it and the words it hands it
+// (catalogue.RuntimeToolModules, catalogue.RuntimeToolEnv, the mesh's own words left out). A bundle the runtime loads
+// nothing of has no Loads: the runtime dropped it, and the composition reads its loads again from the module's build
+// (issue 1126, review: shanks had already applied the drop of systemd-resolved). Nil when running holds no runtime process.
+func ToolsRunning(running []delivery.Composed) map[string][]catalogue.Bundle {
+	runtimeID := catalogue.RuntimeModule + "." + catalogue.RuntimeProcessID()
+	type resource struct {
+		ID     string            `json:"id"`
+		Module string            `json:"module"`
+		Type   string            `json:"type"`
+		Path   string            `json:"path"`
+		Source string            `json:"source"`
+		Digest string            `json:"digest"`
+		Env    map[string]string `json:"env"`
+	}
+	var env map[string]string
+	out := map[string][]catalogue.Bundle{}
+	for _, c := range running {
+		for _, raw := range c.Resources {
+			var r resource
+			if json.Unmarshal(raw, &r) != nil {
+				continue
+			}
+			owner := r.Module
+			if owner == "" {
+				owner, _ = declaration.ModuleGuess(r.ID)
+			}
+			switch {
+			case r.Type == "process" && r.ID == runtimeID && owner == catalogue.RuntimeModule:
+				env = r.Env
+			case r.Type == "archive" && owner != "" && strings.HasPrefix(r.ID, owner+"."+catalogue.BundleID("")):
+				name := strings.TrimPrefix(r.ID, owner+"."+catalogue.BundleID(""))
+				if r.Path == catalogue.BundlePath(owner, name) {
+					out[owner] = append(out[owner], catalogue.Bundle{Name: name, Source: catalogue.Recorded(r.Source), Digest: r.Digest})
+				}
+			}
+		}
+	}
+	if env == nil {
+		return nil
+	}
+	var words map[string]map[string]string
+	_ = json.Unmarshal([]byte(env[catalogue.RuntimeToolEnv]), &words)
+	for _, entry := range strings.Split(env[catalogue.RuntimeToolModules], ",") {
+		module, path, ok := strings.Cut(entry, "=")
+		if !ok || !strings.HasPrefix(path, catalogue.BundleRoot+"/"+module+"/") {
+			continue
+		}
+		name, load, ok := strings.Cut(strings.TrimPrefix(path, catalogue.BundleRoot+"/"+module+"/"), "/")
+		bundles := out[module]
+		i := slices.IndexFunc(bundles, func(b catalogue.Bundle) bool { return b.Name == name })
+		if !ok || i < 0 {
+			continue // no archive of it runs: nothing to load
+		}
+		var own map[string]string
+		for w, v := range words[module] {
+			if w == catalogue.FilesOwnedPaths || w == catalogue.ReadsSecretPlaces {
+				continue // the mesh's to say, composed again
+			}
+			if own == nil {
+				own = map[string]string{}
+			}
+			own[w] = v
+		}
+		bundles[i].Loads = append(bundles[i].Loads, load)
+		bundles[i].Env = own
+	}
+	for _, bundles := range out {
+		sort.Slice(bundles, func(i, j int) bool { return bundles[i].Name < bundles[j].Name })
+	}
+	return out
+}
+
+// runningBundles is the bundles of a module composed as what runs of it (Node.RunsTools): each that runs, with what the
+// runtime loads of it and its words; one the runtime loads nothing of takes its loads and words from the module's build
+// (man: its built bundles, else its build's artifacts, catalogue.BundleLoads), so a drop already applied is undone.
+func runningBundles(runs []catalogue.Bundle, man catalogue.Manifest) []catalogue.Bundle {
+	var out []catalogue.Bundle
+	for _, b := range runs {
+		if len(b.Loads) == 0 {
+			for _, built := range man.Bundles {
+				if built.Name == b.Name {
+					b.Loads, b.Env, b.Launchers, b.Binary = built.Loads, built.Env, built.Launchers, built.Binary
+				}
+			}
+			if man.Build != nil {
+				run := catalogue.RunByAResource(man)
+				for _, a := range man.Build.Artifacts {
+					if a.Kind == catalogue.ArtifactBundle && a.Name == b.Name {
+						b.Loads, b.Env, b.Binary = catalogue.BundleLoads(man, a, run), a.Env, catalogue.BinaryOf(a)
+					}
+				}
+			}
+		}
+		out = append(out, b)
+	}
+	return out
+}
+
 // NamesBuild says a manifest names what a build makes: its build, or a resource naming an artifact. A node cannot
 // compose such a module folded into its own composition: the build of the old form it runs is held by the controller
 // alone (issue 1126).
@@ -318,6 +434,17 @@ func Stub(m catalogue.Manifest) catalogue.Manifest {
 		m.OwnsPaths = catalogue.DeclaredPaths(m)
 	}
 	m.Build = nil
+	// What it hands the provisioner is left out as it runs, not refused for want of a plan (catalogue.Manifest.Stubbed).
+	m.Stubbed = true
+	// Nor is a template its build kept for its own files handed: a stub carries none of them (issue 1126: novox's node
+	// refused "postgres: its build kept a template for consumers, which it does not declare" with postgres held). Its
+	// items stay, and the templates they render through: a held module's contributions to other modules' collections
+	// (seat contributions, shell blocks, seat data) still reach their collectors.
+	if m.Handed != nil {
+		h := *m.Handed
+		h.Templates = nil
+		m.Handed = &h
+	}
 	var dirs []map[string]any
 	for _, r := range m.Resources {
 		if r["type"] == "directory" {

go/compose/composed_test.go

@@ -8,6 +8,7 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/overlay"
 )
 
 func fpFor(c byte) string { return delivery.SourcePrefix2 + strings.Repeat(string(c), 64) }
@@ -96,6 +97,91 @@ func TestCompositionsAreTheDeclarationSplitByModule(t *testing.T) {
 	if _, _, err := Compositions(in, "nowhere", fps, Foreseeing); err == nil {
 		t.Errorf("a node the mesh does not have was composed")
 	}
+
+	// Issue 1126, 2026-10-29: a module composed as what runs of it (folded at a build of the old form, or held) still
+	// contributes to the runtime what the runtime serves of it as it runs (Node.RunsTools): its manifest at the
+	// indexer's commit has no bundles (shanks's runtime lost the folded systemd-resolved, novox's the folded nats), and a
+	// held module's new build's bundles are not delivered.
+	dg := func(c byte) string { return "sha256:" + strings.Repeat(string(c), 64) }
+	runtime := catalogue.Manifest{Module: catalogue.RuntimeModule, Version: "1",
+		OwnSecrets: catalogue.OwnSecrets{"broker": {Path: "/var/lib/mesh/node-tools/broker"}},
+		Bundles: []catalogue.Bundle{{Name: "runtime", Source: catalogue.ArtifactStoreScheme + "node-tools/runtime/blobs/" + dg('a'),
+			Digest: dg('a'), Language: "go", Binary: "node-tools"}}}
+	store := catalogue.Manifest{Module: "artifacts", Version: "1",
+		Serves: map[string]map[string]any{catalogue.ArtifactStoreProvision: {"port": 5100}}}
+	lamp := catalogue.Manifest{Module: "lamp", Version: "1", Tools: []string{"on"},
+		Resources: []map[string]any{{"id": "state", "type": "directory", "path": "/var/lib/lamp", "mode": "0700"}},
+		Build: &catalogue.Build{Artifacts: []catalogue.Artifact{{Name: "tools", Kind: catalogue.ArtifactBundle,
+			Language: "go", System: "arch", From: "cmd/lamp-tools", Env: map[string]string{"LAMP_CONF": "/var/lib/lamp/conf"}}}}}
+	newLamp, err := lamp.Resolve([]catalogue.Built{{Name: "tools", Kind: catalogue.ArtifactBundle,
+		Reference: catalogue.ArtifactStoreScheme + "lamp/tools/blobs/" + dg('c'), Digest: dg('c')}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	served := "lamp=" + catalogue.BundlePath("lamp", "tools") + "/lamp-tools"
+	runtimeRuns := func(dropped bool) delivery.Composed {
+		env := `"MESH_TOOL_MODULES":"` + served + `","MESH_TOOL_ENV":"{\"lamp\":{\"LAMP_CONF\":\"/var/lib/lamp/conf\"}}"`
+		if dropped {
+			env = `"MESH_TOOL_MODULES":""` // the drop already applied (shanks, 2026-10-29)
+		}
+		return delivery.Composed{Node: "anchor", Module: catalogue.RuntimeModule, Resources: []json.RawMessage{json.RawMessage(
+			`{"id":"node-tools.runtime","module":"node-tools","type":"process","name":"node-tools","env":{` + env + `}}`)}}
+	}
+	lampRuns := `{"id":"lamp.bundle-tools","type":"archive","source":"` + catalogue.ArtifactStoreScheme + `lamp/tools/blobs/` + dg('b') +
+		`","digest":"` + dg('b') + `","path":"` + catalogue.BundlePath("lamp", "tools") + `"}`
+	for _, row := range []struct {
+		name    string
+		set     func(n *Node) delivery.Composed // and what runs of lamp
+		fps     map[string]string
+		dropped bool
+	}{
+		{"folded at a build of the old form", func(n *Node) delivery.Composed {
+			n.InOwn = map[string]bool{"lamp": true}
+			n.RunsOwn = &delivery.Composed{Node: "anchor", Resources: []json.RawMessage{json.RawMessage(lampRuns)}}
+			return *n.RunsOwn
+		}, map[string]string{}, false},
+		{"folded, the runtime already dropped it", func(n *Node) delivery.Composed {
+			n.InOwn = map[string]bool{"lamp": true}
+			n.RunsOwn = &delivery.Composed{Node: "anchor", Resources: []json.RawMessage{json.RawMessage(lampRuns)}}
+			return *n.RunsOwn
+		}, map[string]string{}, true},
+		{"held, its new build not delivered", func(n *Node) delivery.Composed {
+			n.Held = map[string]bool{"lamp": true}
+			lr := delivery.Composed{Node: "anchor", Module: "lamp", Resources: []json.RawMessage{json.RawMessage(
+				strings.Replace(lampRuns, `"type"`, `"module":"lamp","type"`, 1))}}
+			n.Kept = map[string]catalogue.Manifest{"lamp": Carried(newLamp, "lamp", &lr)}
+			return lr
+		}, map[string]string{"lamp": fpFor('1')}, false},
+	} {
+		tools := aMesh(t)
+		tools.Catalogue[catalogue.RuntimeModule], tools.Catalogue["artifacts"], tools.Catalogue["lamp"] = runtime, store, lamp
+		anchor := nodeOf(t, &tools, "anchor")
+		anchor.Assigned = append(anchor.Assigned, "artifacts", catalogue.RuntimeModule, "lamp")
+		tools.BusMinted = []string{"anchor." + catalogue.RuntimeModule}
+		anchor.SealingKey = keyOf(t, "anchor")
+		anchor.RunsTools = ToolsRunning([]delivery.Composed{runtimeRuns(row.dropped), row.set(anchor)})
+		row.fps[overlay.Name], row.fps["artifacts"], row.fps[catalogue.RuntimeModule] = fpFor('a'), fpFor('5'), fpFor('e')
+		out, _, _, err := CompositionsIn(tools, "anchor", row.fps, Foreseeing)
+		if err != nil {
+			t.Fatalf("%s: %v", row.name, err)
+		}
+		var env map[string]any
+		for _, c := range out {
+			for _, raw := range c.Resources {
+				var r struct {
+					ID  string         `json:"id"`
+					Env map[string]any `json:"env"`
+				}
+				if json.Unmarshal(raw, &r) == nil && r.ID == "node-tools.runtime" {
+					env = r.Env
+				}
+			}
+		}
+		if env[catalogue.RuntimeToolModules] != served || env[catalogue.RuntimeToolEnv] != `{"lamp":{"LAMP_CONF":"/var/lib/lamp/conf"}}` {
+			t.Errorf("%s: the runtime serves %v with %v, want what runs of lamp, %s", row.name,
+				env[catalogue.RuntimeToolModules], env[catalogue.RuntimeToolEnv], served)
+		}
+	}
 }
 
 // 1943/AC1: the upgrade policies and sources a composition's value may name are the catalogue's own words.

go/compose/frombus/answer.go

@@ -2,8 +2,8 @@ package frombus
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
+	"maps"
 	"regexp"
 	"slices"
 	"sort"
@@ -11,7 +11,6 @@ import (
 
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/compose"
-	"git.novox.be/novox/mesh-sdk/go/declaration"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 )
 
@@ -72,7 +71,7 @@ func Answer(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]st
 			return refuse(fmt.Errorf("frombus: the credentials of %s: %w", s.Node, err))
 		}
 	}
-	composed, skipped, stood, err := composeEach(in, s.Node, fps, false, s.Running, failed)
+	composed, skipped, stood, err := composeEach(in, s.Node, fps, false, s.Running, failed, ranOf(ctx, r, mesh, s.Running, fps))
 	if err != nil {
 		// Not one module's: the node's own (a value served elsewhere, the mesh's network), said once as the node's.
 		if len(failed) == 0 {
@@ -209,15 +208,18 @@ func Answer(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]st
 	return a
 }
 
-// heldAsToday moves each refusal of a module the node holds today (Scope.HeldToday) into Held: the candidate holds it as
-// the node does, which is no change (issue 1126: a seed reproduces today, and today holds it too).
-func heldAsToday(a *delivery.CandidateAnswer, today []string) {
+// heldAsToday moves into Held each refusal of a module the node keeps today as it runs (Scope.HeldToday, with how:
+// held, failed, running a build of the old form): the candidate keeps it as the node does, which is no change (issue
+// 1126: a seed reproduces today, and today keeps them so). Each says how it stands today (ModuleRefused.Today). No
+// module is held behind another (issue 1960): a module that reads from a held one composes with what it last offered.
+func heldAsToday(a *delivery.CandidateAnswer, today map[string]string) {
 	if len(today) == 0 {
 		return
 	}
 	kept := a.Refusals[:0]
 	for _, r := range a.Refusals {
-		if slices.Contains(today, r.Module) {
+		if w, keep := today[r.Module]; keep {
+			r.Today = w
 			a.Held = append(a.Held, r)
 		} else {
 			kept = append(kept, r)
@@ -274,12 +276,18 @@ func standsInFor(x, node string) (string, string) {
 // **A held module is what runs of it** (review of the apply, round 1): composed from what running holds of it
 // (compose.Carried of its own composition there; the node's own carries it wherever it runs there), so what the others
 // read of it (the machine ports its containers publish, the routes reaching it) is what runs, and none of its own
-// composition is in out: the node keeps what it last applied. **What depends on how it is held is held too:** a module
-// whose composition differs when the held ones are composed as their stubs instead is held with them, and a node's own
-// composition that differs (but for the held modules' own resources) refuses the node. And since a held module is
-// composed from its new manifest, which may not be the build's that runs, what reads that manifest is held with it
-// (dependents): the providers of what it contributes to (the proxy its routes), and, when it listens, the filter.
-func composeEach(in compose.Input, node string, fps map[string]string, applied bool, running []delivery.Composed, failed map[string]string) (out map[string]delivery.Composed, skipped, stood []string, err error) {
+// composition is in out: the node keeps what it last applied.
+//
+// **A hold never spreads** (issue 1126, issue 1960: de-spiegel's hold for an unset value held mailu, which held
+// route-proxy, nftables and postgres on novox). No module is held because a module it reads from is held: a consumer,
+// a collector, the provider of what the held one contributes to and the filter where it listens each compose with what
+// the held module last offered. That offer (what it contributes, contributes many, listens on) is its manifest at the
+// build it runs where one is known (ran: a composition of its own running at another build than it is composed at),
+// else the manifest it is composed from. Only the part of the offer that cannot compose is left out, by provision
+// (culprit): de-spiegel's routes, its names unset, leave route-proxy without them while mailu keeps its smtp account,
+// and the hold says so.
+func composeEach(in compose.Input, node string, fps map[string]string, applied bool, running []delivery.Composed, failed map[string]string,
+	ran func(module string) (catalogue.Manifest, bool)) (out map[string]delivery.Composed, skipped, stood []string, err error) {
 	mode := compose.Foreseeing
 	if applied {
 		mode = compose.Reading
@@ -290,43 +298,46 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 			runs[m] = &running[i]
 		}
 	}
-	src := map[string]catalogue.Manifest{} // each held module's manifest before it was held
-	bareOf := map[string]bool{}
-	var hold func(m, why string, bare bool)
-	hold = func(m, why string, bare bool) {
+	src := map[string]catalogue.Manifest{} // each held module's manifest before it was held, offering what it last offered
+	left := map[string]map[string]bool{}   // by held module, what of its offer is left out (leaveOut)
+	hold := func(m, why, leave string) {
 		if _, done := failed[m]; !done {
-			failed[m] = why // a held module tried bare keeps the words it was first held for
+			failed[m] = why // a held module tried again keeps the words it was first held for
 		}
-		first := false
 		if _, ok := src[m]; !ok {
 			man, ok := manifestOn(in, node, m)
 			if !ok {
 				return
 			}
-			src[m], first = man, true
+			if ran != nil {
+				if was, ok := ran(m); ok {
+					man.Contributes, man.ContributesMany, man.Listens = was.Contributes, was.ContributesMany, was.Listens
+				}
+			}
+			src[m] = man
 		}
-		bareOf[m] = bareOf[m] || bare
-		in = heldAs(in, node, m, src[m], bareOf[m], runs[m])
-		if !first {
-			return
-		}
-		// What the others read of its manifest (what it contributes, what it listens on) is its new manifest's, not
-		// necessarily the build's that runs: what reads it is held with it (review of the apply, round 2).
-		for _, r := range dependents(in, node, src[m], failed) {
-			hold(r, "it reads what "+m+" contributes or listens on, and "+m+" is held", false)
+		if leave != "" {
+			if left[m] == nil {
+				left[m] = map[string]bool{}
+			}
+			left[m][leave] = true
+			if leave != leaveAll {
+				failed[m] += "; composed without what it contributes to " + leave + ", which does not compose"
+			}
 		}
+		in = heldAs(in, node, m, src[m], left[m], runs[m])
 	}
 	for _, m := range sortedKeys(failed) {
-		hold(m, failed[m], false)
+		hold(m, failed[m], "")
 	}
 	for {
 		out, skipped, stood, err = compose.CompositionsIn(in, node, fps, mode)
 		if err != nil {
-			module, bare := culprit(in, node, fps, mode, failed, err)
+			module, leave := culprit(in, node, fps, mode, failed, err)
 			if module == "" {
 				return nil, nil, nil, err
 			}
-			hold(module, err.Error(), bare)
+			hold(module, err.Error(), leave)
 			continue
 		}
 		again := false
@@ -346,7 +357,7 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 			}
 			for _, m := range sortedKeys(of) {
 				if _, done := failed[m]; !done {
-					hold(m, "stands in for "+strings.Join(of[m], ", "), false)
+					hold(m, "stands in for "+strings.Join(of[m], ", "), "")
 					again = true
 				}
 			}
@@ -354,17 +365,6 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 				return nil, nil, nil, fmt.Errorf("%w on %s: %s", compose.ErrStoodIn, node, strings.Join(nodes, ", "))
 			}
 		}
-		if !again && len(failed) > 0 {
-			dependent, own := dependsOnHeld(in, node, fps, mode, out, src, bareOf, failed)
-			if own {
-				return nil, nil, nil, fmt.Errorf("frombus: %s's own composition depends on how %s, held, is composed, and is not applied",
-					node, strings.Join(sortedKeys(failed), ", "))
-			}
-			for _, m := range dependent {
-				hold(m, "what it composes of "+strings.Join(sortedKeys(failed), ", ")+", held, is not what runs of them", false)
-				again = true
-			}
-		}
 		if !again {
 			break
 		}
@@ -373,117 +373,9 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 	return out, skipped, stood, nil
 }
 
-// dependsOnHeld composes in again with each held module as its stub rather than as what runs of it, and answers the
-// modules, not held, whose composition differs between the two (sorted), and own when the node's own composition does
-// but for the held modules' own resources. A composition of stubs that fails says nothing more: what runs composed.
-func dependsOnHeld(in compose.Input, node string, fps map[string]string, mode compose.Mode, asRuns map[string]delivery.Composed,
-	src map[string]catalogue.Manifest, bareOf map[string]bool, failed map[string]string) (dependent []string, own bool) {
-	stubs := in
-	for _, m := range sortedKeys(failed) {
-		if man, ok := src[m]; ok {
-			stubs = heldAs(stubs, node, m, man, bareOf[m], nil)
-		}
-	}
-	asStubs, _, _, err := compose.CompositionsIn(stubs, node, fps, mode)
-	if err != nil {
-		return nil, false
-	}
-	isHeld := func(m string) bool { _, ok := failed[m]; return ok }
-	keys := map[string]bool{}
-	for k := range asRuns {
-		keys[k] = true
-	}
-	for k := range asStubs {
-		keys[k] = true
-	}
-	for _, k := range sortedKeys(keys) {
-		a, inA := asRuns[k]
-		b, inB := asStubs[k]
-		m := a.Module
-		if !inA {
-			m = b.Module
-		}
-		if m != "" && isHeld(m) {
-			continue
-		}
-		if m == "" {
-			a, b = withoutHeld(a, isHeld), withoutHeld(b, isHeld)
-		}
-		da, errA := delivery.ComposedDigestOf(a)
-		db, errB := delivery.ComposedDigestOf(b)
-		if inA == inB && errA == nil && errB == nil && da == db {
-			continue
-		}
-		if m == "" {
-			own = true
-			continue
-		}
-		dependent = append(dependent, m)
-	}
-	return dependent, own
-}
-
-// withoutHeld is the node's own composition c without the resources of a held module (its id naming it) and without
-// its filled paths, for comparing the rest.
-func withoutHeld(c delivery.Composed, isHeld func(string) bool) delivery.Composed {
-	out := c
-	out.Filled = nil
-	out.Resources = nil
-	for _, raw := range c.Resources {
-		var head struct {
-			ID     string `json:"id"`
-			Module string `json:"module"`
-		}
-		_ = json.Unmarshal(raw, &head)
-		owner := head.Module
-		if owner == "" {
-			owner, _ = declaration.ModuleGuess(head.ID)
-		}
-		if owner != "" && isHeld(owner) {
-			continue
-		}
-		out.Resources = append(out.Resources, raw)
-	}
-	return out
-}
-
-// dependents is, of the modules placed on node and not held, those that read what man says to them: each that provides
-// what man contributes to (the proxy its routes), and, when man listens on a port, each that holds the filter (the
-// openings).
-func dependents(in compose.Input, node string, man catalogue.Manifest, failed map[string]string) []string {
-	to := map[string]bool{}
-	for p := range man.Contributes {
-		to[p] = true
-	}
-	for p := range man.ContributesMany {
-		to[p] = true
-	}
-	listens := len(man.Listens) > 0
-	if len(to) == 0 && !listens {
-		return nil
-	}
-	var out []string
-	for _, m := range assignedOn(in, node) {
-		if _, held := failed[m]; held || m == man.Module {
-			continue
-		}
-		pm, ok := manifestOn(in, node, m)
-		if !ok {
-			continue
-		}
-		if listens && pm.Filtering != nil {
-			out = append(out, m)
-			continue
-		}
-		for _, o := range pm.Provides {
-			if to[o.Name] {
-				out = append(out, m)
-				break
-			}
-		}
-	}
-	return out
-}
+// leaveAll leaves out the whole of a held module's offer and its own secrets (a bare stub); any other word leaves out
+// what it contributes to that provision alone.
+const leaveAll = "*"
 
 // assignedOn is the modules placed on node, in placement order.
 func assignedOn(in compose.Input, node string) []string {
@@ -508,18 +400,14 @@ func manifestOn(in compose.Input, node, module string) (catalogue.Manifest, bool
 	return man, ok
 }
 
-// culprit is the module placed on node whose composition the error is of: the first, in placement order, whose stub
-// (compose.Stub) makes the composition in mode succeed or fail otherwise; empty when none does (the error is not one
-// module's). Modules already refused are passed over. A module whose stub still fails the same is tried bare (its stub
-// contributing nothing, bare true): a refusal of what it contributes is its own, which the stub keeps (issue 1126,
-// seed-8: de-spiegel's route names on novox, an unset required value, refused the whole node).
-func culprit(in compose.Input, node string, fps map[string]string, mode compose.Mode, failed map[string]string, err error) (string, bool) {
-	var assigned []string
-	for _, n := range in.Nodes {
-		if n.Name == node {
-			assigned = n.Assigned
-		}
-	}
+// culprit is the module placed on node whose composition the error is of, and what of its offer to leave out: the
+// first, in placement order, whose stub (compose.Stub) makes the composition in mode succeed or fail otherwise (leave
+// ""); else the first whose stub without what it contributes to one provision does (leave that provision: de-spiegel's
+// routes, its names unset, and not its smtp account, issue 1960); else the first whose bare stub does (leaveAll: its
+// stub contributing nothing, its own secret never issued, issue 1126 seed-8). Empty when none does (the error is not
+// one module's). Modules already refused are passed over for their stub.
+func culprit(in compose.Input, node string, fps map[string]string, mode compose.Mode, failed map[string]string, err error) (string, string) {
+	assigned := assignedOn(in, node)
 	// Only the modules the error names: the words of a module's refusal name it. Each try is a whole composition, so a
 	// refusal naming none is no module's, answered at once rather than after a composition per module (issue 1126: ace's
 	// answer took 7m46s).
@@ -529,65 +417,97 @@ func culprit(in compose.Input, node string, fps map[string]string, mode compose.
 			order = append(order, m)
 		}
 	}
-	changes := func(m string, bare bool) bool {
-		_, _, _, again := compose.CompositionsIn(stubbed(in, node, m, bare), node, fps, mode)
+	changes := func(m, leave string) bool {
+		_, _, _, again := compose.CompositionsIn(stubbed(in, node, m, leave), node, fps, mode)
 		return again == nil || again.Error() != err.Error()
 	}
 	for _, m := range order {
 		if _, done := failed[m]; done {
 			continue
 		}
-		if changes(m, false) {
-			return m, false
-		}
-	}
-	var kept map[string]catalogue.Manifest
-	for _, n := range in.Nodes {
-		if n.Name == node {
-			kept = n.Kept
+		if changes(m, "") {
+			return m, ""
 		}
 	}
 	for _, m := range order {
-		// One already held is tried bare too, once: held for its build, its stub may still refuse (its own secret
-		// never issued, issue 1126).
-		if _, done := failed[m]; done && isBare(kept[m]) {
+		man, ok := manifestOn(in, node, m)
+		if !ok {
 			continue
 		}
-		if changes(m, true) {
-			return m, true
+		// One already held is tried again too: held for its build, its stub may still refuse (its own secret never
+		// issued, issue 1126). A provision named in the error is tried first, each at one more composition.
+		var to []string
+		for p := range man.Contributes {
+			to = append(to, p)
+		}
+		for p := range man.ContributesMany {
+			if _, both := man.Contributes[p]; !both {
+				to = append(to, p)
+			}
+		}
+		sort.SliceStable(to, func(i, j int) bool {
+			return strings.Contains(err.Error(), " "+to[i]) && !strings.Contains(err.Error(), " "+to[j])
+		})
+		for _, p := range to {
+			if changes(m, p) {
+				return m, p
+			}
+		}
+		if isBare(man) {
+			continue
+		}
+		if changes(m, leaveAll) {
+			return m, leaveAll
 		}
 	}
-	return "", false
+	return "", ""
 }
 
-// isBare says a stub contributes nothing and declares no own secret (stubbed, bare).
+// isBare says a stub contributes nothing and declares no own secret (stubbed, leaveAll).
 func isBare(m catalogue.Manifest) bool {
 	return len(m.Contributes) == 0 && len(m.ContributesMany) == 0 && len(m.OwnSecrets) == 0
 }
 
 // stubbed is in with module held on node as its stub alone (heldAs, nothing of it running), from the manifest node
-// composes it from: a culprit's try.
-func stubbed(in compose.Input, node, module string, bare bool) compose.Input {
+// composes it from, leave left out of its offer: a culprit's try.
+func stubbed(in compose.Input, node, module, leave string) compose.Input {
 	man, ok := manifestOn(in, node, module)
 	if !ok {
 		return in
 	}
-	return heldAs(in, node, module, man, bare, nil)
+	var left map[string]bool
+	if leave != "" {
+		left = map[string]bool{leave: true}
+	}
+	return heldAs(in, node, module, man, left, nil)
 }
 
 // heldAs is in with module held on node (compose.Node.Held): composed from man as what runs of it (compose.Carried of
-// runs; its stub, compose.Stub, when runs is nil or holds nothing of it), as node's Kept; bare, contributing nothing to
-// what it requires and declaring no own secret: none of a held module's own composition is applied, so what it has not
-// been issued (restic's repository on a node it never ran on) is no refusal of the rest.
-func heldAs(in compose.Input, node, module string, man catalogue.Manifest, bare bool, runs *delivery.Composed) compose.Input {
+// runs; its stub, compose.Stub, when runs is nil or holds nothing of it), as node's Kept; with what left names out of
+// its offer: a provision's contributions, or with leaveAll everything it contributes and its own secrets, none of a
+// held module's own composition being applied, so what it has not been issued (restic's repository on a node it never
+// ran on) is no refusal of the rest.
+func heldAs(in compose.Input, node, module string, man catalogue.Manifest, left map[string]bool, runs *delivery.Composed) compose.Input {
 	out := in
 	out.Nodes = append([]compose.Node(nil), in.Nodes...)
 	for i := range out.Nodes {
 		if out.Nodes[i].Name != node {
 			continue
 		}
-		if bare {
+		if left[leaveAll] {
 			man.Contributes, man.ContributesMany, man.OwnSecrets = nil, nil, nil
+		} else if len(left) > 0 {
+			contributes := map[string]map[string]any{}
+			for p, v := range man.Contributes {
+				if !left[p] {
+					contributes[p] = v
+				}
+			}
+			many := maps.Clone(man.ContributesMany)
+			for p := range left {
+				delete(many, p)
+			}
+			man.Contributes, man.ContributesMany = contributes, many
 		}
 		kept := make(map[string]catalogue.Manifest, len(out.Nodes[i].Kept)+1)
 		for k, v := range out.Nodes[i].Kept {

go/compose/frombus/answer_rows_test.go

@@ -93,17 +93,25 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	}
 	// Issue 1126: a module the node holds today that the candidate holds too is held as today, no refusal: with every
 	// refused module held today the verdict is no refusal, and each is named under Held.
-	today := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: []string{"api", "spiegel", "web"}},
+	today := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: map[string]string{"api": "held", "spiegel": "held", "web": "held"}},
 		map[string]string{"lemurs": fp("e"), "web": fp("1"), "api": fp("2"), "spiegel": fp("3")}, nil, "p-h1", 3)
 	if today.Verdict == delivery.CandidateRefused || len(today.Refusals) != 0 || len(today.Held) != 3 || today.Held[0].Why == "" {
 		t.Errorf("held as today: %+v", today)
 	}
 	// A refused module the node does not hold today stays a refusal: holding only api today leaves spiegel and web refused.
-	part := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: []string{"api"}},
+	part := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: map[string]string{"api": "held"}},
 		map[string]string{"lemurs": fp("e"), "web": fp("1"), "api": fp("2"), "spiegel": fp("3")}, nil, "p-h1", 3)
 	if part.Verdict != delivery.CandidateRefused || len(part.Refusals) != 2 || len(part.Held) != 1 || part.Held[0].Module != "api" {
 		t.Errorf("held as today in part: %+v", part)
 	}
+	// No module is held behind one kept today (issue 1960): mailu's own refusal stays a refusal beside de-spiegel's hold.
+	if a := (delivery.CandidateAnswer{Refusals: []delivery.ModuleRefused{{Module: "de-spiegel", Why: "a value is unset"},
+		{Module: "mailu", Why: "no build"}}}); true {
+		heldAsToday(&a, map[string]string{"de-spiegel": "runs a build of the old form"})
+		if len(a.Refusals) != 1 || a.Refusals[0].Module != "mailu" || len(a.Held) != 1 {
+			t.Errorf("held as today spreads: %+v", a)
+		}
+	}
 
 	// The fold: spiegel runs inside the node's own composition at a build of the old form. Its resources are carried as
 	// they run, each after the one it runs after: the node's own is the one it runs, and the node composes itself.
@@ -286,6 +294,31 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if got, want := catalogue.DeclaredPaths(compose.Carried(f1, "f1-circuits", &f1runs)), catalogue.DeclaredPaths(f1); !reflect.DeepEqual(got, want) {
 		t.Errorf("f1-circuits carried owns %v, want what the controller composes from its manifest, %v", got, want)
 	}
+	// Issue 1126: a held module hands no template its build kept for a file it no longer carries (novox's node:
+	// "postgres: its build kept a template for consumers"), but keeps its items and their templates, so what it
+	// contributes to other modules' collections still reaches them.
+	for _, row := range []struct {
+		name   string
+		handed *catalogue.Handed
+		items  []catalogue.Item
+	}{
+		{"templates and items", &catalogue.Handed{Templates: map[string]string{"consumers": "files/consumers.json"},
+			Items: map[string]string{"routes": "files/routes.tmpl"}}, []catalogue.Item{{Collection: "routes", Content: "x"}}},
+		{"items alone", nil, []catalogue.Item{{Collection: "routes", Content: "x"}}},
+	} {
+		kept := f1
+		kept.Handed, kept.Items = row.handed, row.items
+		st := compose.Stub(kept)
+		if st.Handed != nil && st.Handed.Templates != nil {
+			t.Errorf("%s: a stub hands templates %v", row.name, st.Handed.Templates)
+		}
+		if !reflect.DeepEqual(st.Items, row.items) {
+			t.Errorf("%s: a stub collects %+v, want its items %+v", row.name, st.Items, row.items)
+		}
+		if row.handed != nil && (st.Handed == nil || !reflect.DeepEqual(st.Handed.Items, row.handed.Items) || row.handed.Templates == nil) {
+			t.Errorf("%s: a stub hands item templates %+v, want %v and its manifest untouched", row.name, st.Handed, row.handed.Items)
+		}
+	}
 	var k1, k2 any
 	_ = json.Unmarshal(keptComposed, &k1)
 	_ = json.Unmarshal(keptFile, &k2)
@@ -297,23 +330,26 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	// de-spiegel folded, and its manifest at the indexer's commit (e25e1beb, captured) asks four required config values
 	// for its route names that nothing sets. novox answered the whole candidate refused ("de-spiegel contributing
 	// praktijk to route says ${setting:praktijk-name} ...": its stub still contributed the route). Only de-spiegel is
-	// refused, in the config form's words, and proxy, which receives its routes (what it would compose lacks them: review
-	// of the apply, round 1); the rest is judged.
+	// refused, in the config form's words; the rest is judged. Issue 1960, novox's chain on 2026-10-29: the hold spread
+	// to mailu (its smtp provider) and proxy (its route provider), and from them on. Neither is held now: proxy composes
+	// without de-spiegel's routes, which do not compose, and mailu with its smtp account, which does.
 	spiegel, err := os.ReadFile("testdata/de-spiegel-e25e1beb.module.json")
 	if err != nil {
 		t.Fatal(err)
 	}
-	proxy := []byte(`{"module":"proxy","version":"1","capabilities":["systemd"],"provides":[{"name":"route","scope":"mesh"},{"name":"smtp","scope":"mesh"}],` +
+	proxy := []byte(`{"module":"proxy","version":"1","capabilities":["systemd"],"provides":[{"name":"route","scope":"mesh"}],` +
 		`"resources":[{"id":"service","type":"service","unit":"proxy.service","state":"running","boot":"enabled"}]}`)
-	b = mk("lemurs", overlay.Name, "proxy", "de-spiegel")
-	for m, raw := range map[string][]byte{"de-spiegel": spiegel, "proxy": proxy} {
+	mailu := []byte(`{"module":"mailu","version":"1","capabilities":["systemd"],"provides":[{"name":"smtp","scope":"mesh"}],` +
+		`"resources":[{"id":"service","type":"service","unit":"mailu.service","state":"running","boot":"enabled"}]}`)
+	b = mk("lemurs", overlay.Name, "mailu", "proxy", "de-spiegel")
+	for m, raw := range map[string][]byte{"de-spiegel": spiegel, "proxy": proxy, "mailu": mailu} {
 		b.manifests[delivery.ManifestDigest(raw)] = raw
 		b.modules[m] = delivery.Module{Manifest: delivery.ManifestDigest(raw)}
 	}
 	p = b.placements["n1"]
 	p.Decided.Endpoint = "n1.example:51820"
 	b.placements["n1"] = p
-	fps = map[string]string{"lemurs": fp("e"), "proxy": fp("f")}
+	fps = map[string]string{"lemurs": fp("e"), "proxy": fp("f"), "mailu": fp("d")}
 	a = Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), InOwn: []string{"de-spiegel"}}, fps, nil, "p-h1", 3)
 	refused = nil
 	for _, r := range a.Refusals {
@@ -322,11 +358,13 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 			t.Errorf("de-spiegel is refused in other words than its config form's: %s", r.Why)
 		}
 	}
-	if a.Refused != "" || !reflect.DeepEqual(refused, []string{"de-spiegel", "proxy"}) {
-		t.Errorf("a module's own refusal: %+v, want de-spiegel refused with proxy, which receives its routes, the node not", a)
+	if a.Refused != "" || !reflect.DeepEqual(refused, []string{"de-spiegel"}) {
+		t.Errorf("a module's own refusal: %+v, want de-spiegel refused alone, the node, mailu and proxy not", a)
 	}
-	if !slices.ContainsFunc(a.Added, func(m delivery.ModuleAdded) bool { return m.Module == "lemurs" }) {
-		t.Errorf("lemurs, which composes, is not judged beside de-spiegel's refusal: %+v", a)
+	for _, m := range []string{"lemurs", "mailu", "proxy"} {
+		if !slices.ContainsFunc(a.Added, func(x delivery.ModuleAdded) bool { return x.Module == m }) {
+			t.Errorf("%s, which composes, is not judged beside de-spiegel's refusal: %+v", m, a)
+		}
 	}
 
 	// (E) Issue 1126, the applying path (review of the seed): the composition novox applies follows the same rule. It
@@ -360,16 +398,13 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if err != nil {
 		t.Fatalf("de-spiegel's own refusal refuses the node's whole composition: %v", err)
 	}
-	if len(held) != 2 || !strings.Contains(held["de-spiegel"], "${config:praktijk-name}") || !strings.Contains(held["proxy"], "de-spiegel") {
-		t.Errorf("held %v, want de-spiegel in its config form's words, and proxy for its routes", held)
+	if len(held) != 1 || !strings.Contains(held["de-spiegel"], "${config:praktijk-name}") || !strings.Contains(held["de-spiegel"], "without what it contributes to route") {
+		t.Errorf("held %v, want de-spiegel alone, in its config form's words, composed without its routes", held)
 	}
-	lemursKey, _ := delivery.ComposedKey("n1", "lemurs", fps["lemurs"])
-	proxyKey, _ := delivery.ComposedKey("n1", "proxy", fps["proxy"])
-	if _, ok := got[lemursKey]; !ok {
-		t.Errorf("lemurs, which composes, is not composed beside de-spiegel's refusal: %v", sortedKeys(got))
-	}
-	if _, ok := got[proxyKey]; ok {
-		t.Errorf("proxy is composed without the routes of held de-spiegel: %v", sortedKeys(got))
+	for _, m := range []string{"lemurs", "mailu", "proxy"} {
+		if key, _ := delivery.ComposedKey("n1", m, fps[m]); got[key].Module != m {
+			t.Errorf("%s is not composed beside de-spiegel's hold: %v", m, sortedKeys(got))
+		}
 	}
 	carries := func(c delivery.Composed, what string) {
 		t.Helper()
@@ -400,8 +435,8 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 
 	// (G) A held module that runs a composition of its own (review of the apply, round 1, finding 2): what the others
 	// compose of it is what runs, never its stub's. site listens on 8080, placed at the machine's 20005, and its own
-	// secret was never issued here: held, the filter must not open 8080 and drop the 20005 that runs. A module whose
-	// composition depends on how site is held (here the filter) is held with it.
+	// secret was never issued here: held, the filter must not open 8080 and drop the 20005 that runs. The filter, which
+	// reads what site listens on, composes with it (issue 1960: a hold never spreads).
 	site := []byte(`{"module":"site","version":"1","capabilities":["container-runtime"],` +
 		`"listens":[{"port":8080,"from":"mesh","why":"the site"}],"own-secrets":{"key":"${dir:state}/key"},` +
 		`"resources":[{"id":"state","type":"directory","path":"/var/lib/site","mode":"0700"},` +
@@ -427,8 +462,12 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 		json.RawMessage(`{"id":"site.state","module":"site","type":"directory","path":"/var/lib/site","mode":"0700"}`),
 		json.RawMessage(`{"id":"site.server","module":"site","type":"container","name":"site","image":"registry.example/site@sha256:` + strings.Repeat("c", 64) + `","ports":["10.77.0.1:20005:8080"]}`)}}
 	got, _, held, err = Compose(ctx, b, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
-	if err != nil || held["site"] == "" || held["nft"] == "" {
-		t.Fatalf("site, its own secret never issued: %v, held %v; want site held, and the filter, which depends on it", err, held)
+	nftKey, _ := delivery.ComposedKey("n1", "nft", fps["nft"])
+	if err != nil || held["site"] == "" || held["nft"] != "" || got[nftKey].Module != "nft" {
+		t.Fatalf("site, its own secret never issued: %v, held %v; want site held alone, and the filter composed", err, held)
+	}
+	if rules, _ := json.Marshal(got[nftKey].Resources); !strings.Contains(string(rules), "dport 20005") {
+		t.Errorf("the filter drops held site's opening where it runs (20005): %s", rules)
 	}
 	for key, c := range got {
 		for _, raw := range c.Resources {
@@ -437,10 +476,56 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 			}
 		}
 	}
+	// (G2) Issue 1126, the spreading hold: a held module is no dependence of its neighbours. site, held, provides page, and
+	// app requires and binds it: app composes against what runs of site and is not held (novox's seed held every postgres
+	// consumer behind de-spiegel's hold, "what it composes of …, held, is not what runs of them").
+	provider := []byte(strings.Replace(string(site), `"listens":`, `"provides":[{"name":"page","scope":"node"}],"serves":{"page":{"port":8080}},"listens":`, 1))
+	app := []byte(`{"module":"app","version":"1","capabilities":["systemd"],"requires":["page"],"binds":{"page":"/etc/app/page.json"},` +
+		`"resources":[{"id":"service","type":"service","unit":"app.service","state":"running","boot":"enabled"}]}`)
+	b2 := mk("lemurs", overlay.Name, "site", "nft", "app")
+	for m, raw := range map[string][]byte{"site": provider, "nft": nft, "app": app} {
+		b2.manifests[delivery.ManifestDigest(raw)] = raw
+		b2.modules[m] = delivery.Module{Manifest: delivery.ManifestDigest(raw)}
+	}
+	p2 := b2.placements["n1"]
+	p2.Decided.Endpoint = "n1.example:51820"
+	for i := range p2.Modules {
+		if p2.Modules[i].Module == "site" {
+			p2.Modules[i].Ports = map[string]int{"8080": 20005}
+		}
+	}
+	b2.placements["n1"] = p2
+	b2.records["n1"] = rec
+	b2.held = true
+	fps["app"] = fp("9")
+	got, _, held, err = Compose(ctx, b2, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
+	appKey, _ := delivery.ComposedKey("n1", "app", fps["app"])
+	if _, composed := got[appKey]; err != nil || held["site"] == "" || held["app"] != "" || !composed {
+		t.Errorf("a consumer of held site: %v, held %v; want site held, and app composed against what runs of it", err, held)
+	}
+	if bound, _ := json.Marshal(got[appKey].Resources); !strings.Contains(string(bound), "20005") {
+		t.Errorf("app's binding does not reach held site where it runs (20005): %s", bound)
+	}
+	delete(fps, "app")
+	// A held module's offer is left out by provision, never whole when one part composes (issue 1960): de-spiegel's
+	// routes, its names unset, leave the proxy without them, and its smtp account stays with mailu.
+	withProxy := compose.Input{Catalogue: map[string]catalogue.Manifest{},
+		Nodes: []compose.Node{{Name: "n1", Assigned: []string{"feeder"}}}}
+	feeder := catalogue.Manifest{Module: "feeder", Contributes: map[string]map[string]any{"route": {"name": "x"}, "smtp": {"account": "feeder"}},
+		OwnSecrets: catalogue.OwnSecrets{"key": {Path: "/k"}}}
+	for _, row := range []struct {
+		left             map[string]bool
+		route, smtp, own bool
+	}{{nil, true, true, true}, {map[string]bool{"route": true}, false, true, true}, {map[string]bool{leaveAll: true}, false, false, false}} {
+		k := heldAs(withProxy, "n1", "feeder", feeder, row.left, nil).Nodes[0].Kept["feeder"]
+		if _, r := k.Contributes["route"]; r != row.route || (k.Contributes["smtp"] != nil) != row.smtp || (len(k.OwnSecrets) > 0) != row.own {
+			t.Errorf("held leaving out %v offers %+v, own secrets %v", row.left, k.Contributes, k.OwnSecrets)
+		}
+	}
 	// (H) Review of the apply, round 2: a held module is composed from its new manifest, so what the others read of its
 	// manifest (its listens, what it contributes) may not be what runs. site's new manifest moves it to 9090 while the
-	// build that runs listens on 8080: the filter, the holder of what site listens on, is held with it, and nothing
-	// applied opens 9090.
+	// build that runs (7) listens on 8080. The filter composes with what site last offered, its manifest at the build
+	// that runs (issue 1960: a hold never spreads), so it opens 8080 and nothing applied opens 9090.
 	moved := []byte(strings.Replace(string(site), `"port":8080`, `"port":9090`, 1))
 	b.manifests[delivery.ManifestDigest(moved)] = moved
 	b.modules["site"] = delivery.Module{Manifest: delivery.ManifestDigest(moved)}
@@ -449,9 +534,15 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	}
 	b.placements["n1"] = p
 	siteRuns.Resources[1] = json.RawMessage(`{"id":"site.server","module":"site","type":"container","name":"site","image":"registry.example/site@sha256:` + strings.Repeat("c", 64) + `","ports":["8080"]}`)
+	siteRuns.FP = fp("7")
+	b.manifests[delivery.ManifestDigest(site)] = site
+	b.builds["site "+fp("7")] = &delivery.BuilderBuild{State: delivery.BuildDone, Manifest: delivery.ManifestDigest(site)}
 	got, _, held, err = Compose(ctx, b, Mesh{}, Scope{Node: "n1", Running: []delivery.Composed{siteRuns}}, fps)
-	if err != nil || held["site"] == "" || held["nft"] == "" {
-		t.Errorf("site moved to 9090 in its new manifest: %v, held %v; want site held, and the filter with it", err, held)
+	if err != nil || held["site"] == "" || held["nft"] != "" {
+		t.Errorf("site moved to 9090 in its new manifest: %v, held %v; want site held alone", err, held)
+	}
+	if rules, _ := json.Marshal(got[nftKey].Resources); !strings.Contains(string(rules), "dport 8080") {
+		t.Errorf("the filter drops what held site last offered (8080): %s", rules)
 	}
 	for key, c := range got {
 		for _, raw := range c.Resources {

go/compose/frombus/frombus.go

@@ -83,6 +83,16 @@ type Reader interface {
 	Served(ctx context.Context, node, module string, keys []string) (map[string]any, error)
 }
 
+// SignersReader is a Reader that also reads the vault's public authority from its state `signers` (delivery.SignersBucket,
+// key delivery.SignersAuthorityKey; ADR 0550 §2). A Reader that has it composes the mesh's authority as a bundle, the
+// controller's and the vault's; one that has not, or that answers none, composes the controller's alone, as before.
+type SignersReader interface {
+	// VaultAuthority is the vault's authority certificate as PEM, checked (delivery.DecodeSignerAuthority); empty when the
+	// vault has published none. A read that fails is said by the reader and answered empty: a node that may not read the
+	// state yet composes as before rather than not at all.
+	VaultAuthority(ctx context.Context) string
+}
+
 // Mesh is what is true of the whole mesh and is no part's state on the bus yet: the private network's range and the
 // internal names' suffix as genesis was told them, and the mesh's authority certificate (public). Empty fields take
 // compose's defaults.
@@ -124,10 +134,10 @@ type Scope struct {
 	Placements map[string]*delivery.Placement
 	InOwn      []string
 	Running    []delivery.Composed
-	// HeldToday is, in an answer, the modules the node holds today ("node" for its own composition): their have's phase
-	// is held, or they are held inside its own composition. A candidate that holds one too holds it as today, which is
-	// said under CandidateAnswer.Held and is no refusal (issue 1126).
-	HeldToday []string
+	// HeldToday is, in an answer, the modules the node keeps today as they run ("node" for its own composition), each with
+	// how ("held", "failed", "runs a build of the old form"): a candidate that cannot compose one, or holds one only
+	// behind one of them, keeps it as today, which is said under CandidateAnswer.Held and is no refusal (issue 1126).
+	HeldToday map[string]string
 	// SameValue, in an answer, says whether two sealed values open to the same value (the node opens them with its own
 	// key), so a differing resource shows a value sealed again as such (delivery.CompareComposedWith). Nil shows them
 	// as differing.
@@ -223,12 +233,14 @@ func input(ctx context.Context, r Reader, mesh Mesh, s Scope, refuse func(module
 			}
 		}
 	}
-	parse := func(raw []byte) (catalogue.Manifest, error) {
-		if mesh.Predefined != nil {
-			return catalogue.ParseManifestWith(raw, mesh.Predefined)
+	// And the vault's authority beside it, once the vault publishes one (ADR 0550 §2): a certificate either signed checks
+	// against the bundle. The controller's stays while a certificate it issued is in a node's record.
+	if sr, ok := r.(SignersReader); ok {
+		if vault := sr.VaultAuthority(ctx); vault != "" {
+			in.Authority = delivery.AuthorityBundle(in.Authority, vault)
 		}
-		return catalogue.ParseManifestForInputs(raw)
 	}
+	parse := parser(mesh)
 	read := func(module, digest string) (catalogue.Manifest, error) {
 		raw, err := r.Manifest(ctx, digest)
 		if err != nil {
@@ -296,6 +308,8 @@ func input(ctx context.Context, r Reader, mesh Mesh, s Scope, refuse func(module
 			}
 		}
 		if node == s.Node {
+			// What its runtime serves as it runs: what a module composed as what runs of it contributes there (issue 1126).
+			n.RunsTools = compose.ToolsRunning(s.Running)
 			for _, module := range s.InOwn {
 				if n.InOwn == nil {
 					n.InOwn = map[string]bool{}
@@ -408,10 +422,47 @@ func Compose(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]s
 			return nil, nil, held, fmt.Errorf("frombus: the credentials of %s: %w", s.Node, err)
 		}
 	}
-	out, skipped, _, err = composeEach(in, s.Node, fps, true, s.Running, held)
+	out, skipped, _, err = composeEach(in, s.Node, fps, true, s.Running, held, ranOf(ctx, r, mesh, s.Running, fps))
 	return out, skipped, held, err
 }
 
+// parser reads a manifest as the indexer does, against the mesh's predefined keys when given.
+func parser(mesh Mesh) func([]byte) (catalogue.Manifest, error) {
+	return func(raw []byte) (catalogue.Manifest, error) {
+		if mesh.Predefined != nil {
+			return catalogue.ParseManifestWith(raw, mesh.Predefined)
+		}
+		return catalogue.ParseManifestForInputs(raw)
+	}
+}
+
+// ranOf is what a module last offered the others, read when it is held (composeEach, issue 1960): its manifest at the
+// build its own composition runs at (running), where that is another build than the one it is composed at (fps) and
+// the builder holds it done. False where nothing is known of it (it runs no composition of its own, it runs the build
+// it is composed at, or its build is unread): the manifest it is composed from is its offer then. Only what it says to
+// others is taken of it, which needs no take-in of its artifacts.
+func ranOf(ctx context.Context, r Reader, mesh Mesh, running []delivery.Composed, fps map[string]string) func(string) (catalogue.Manifest, bool) {
+	parse := parser(mesh)
+	return func(module string) (catalogue.Manifest, bool) {
+		for _, c := range running {
+			if c.Module != module || c.FP == "" || c.FP == fps[module] {
+				continue
+			}
+			b, err := r.Build(ctx, module, c.FP)
+			if err != nil || b == nil || b.State != delivery.BuildDone || b.Manifest == "" {
+				return catalogue.Manifest{}, false
+			}
+			raw, err := r.Manifest(ctx, b.Manifest)
+			if err != nil {
+				return catalogue.Manifest{}, false
+			}
+			man, err := parse(raw)
+			return man, err == nil
+		}
+		return catalogue.Manifest{}, false
+	}
+}
+
 // fromBuilds puts in the built manifest of each module placed on the composing node, at the trunk's FP2, and of each
 // module it keeps at another build (Scope.KeptAt, into its node's Kept), read from the builder's done key and resolved
 // by the one take-in rule (takein.Manifest), a templates archive read in the artifact store as the node reaches it

go/compose/frombus/frombus_test.go

@@ -25,14 +25,15 @@ import (
 
 // bus is a Reader over values held in memory, counting whose config values were read.
 type bus struct {
-	placements map[string]delivery.Placement
-	records    map[string]delivery.NodeRecord
-	modules    map[string]delivery.Module
-	manifests  map[string][]byte
-	values     map[string]map[string]any // by node.module
-	valuesRead []string
-	own        []compose.OwnSecretRow
-	ownErr     error
+	vaultAuthority string
+	placements     map[string]delivery.Placement
+	records        map[string]delivery.NodeRecord
+	modules        map[string]delivery.Module
+	manifests      map[string][]byte
+	values         map[string]map[string]any // by node.module
+	valuesRead     []string
+	own            []compose.OwnSecretRow
+	ownErr         error
 	// asked is every consumer credential asked; the fake refuses the whole ask, as the vault's own does, for a consuming
 	// module its placement does not put on the node.
 	asked []compose.CredentialKey
@@ -44,6 +45,8 @@ type bus struct {
 	served     map[string]map[string]any
 	servedRead []string
 	buildsRead []string
+	// held answers every credential asked as held, sealed to the consumer.
+	held bool
 }
 
 func (b *bus) Build(_ context.Context, module, fp string) (*delivery.BuilderBuild, error) {
@@ -74,6 +77,7 @@ func (b *bus) Served(_ context.Context, node, module string, keys []string) (map
 func (b *bus) Placements(context.Context) (map[string]delivery.Placement, error) {
 	return b.placements, nil
 }
+func (b *bus) VaultAuthority(context.Context) string                           { return b.vaultAuthority }
 func (b *bus) Records(context.Context) (map[string]delivery.NodeRecord, error) { return b.records, nil }
 func (b *bus) Modules(context.Context) (map[string]delivery.Module, error)     { return b.modules, nil }
 func (b *bus) Manifest(_ context.Context, digest string) ([]byte, error) {
@@ -87,7 +91,7 @@ func (b *bus) OwnSecrets(context.Context, string) ([]compose.OwnSecretRow, error
 	return b.own, b.ownErr
 }
 
-func (b *bus) Credentials(_ context.Context, node string, asConsumer, _ []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
+func (b *bus) Credentials(_ context.Context, node string, asConsumer, asProvider []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
 	b.asked = append(b.asked, asConsumer...)
 	for _, k := range asConsumer {
 		placed := false
@@ -98,7 +102,17 @@ func (b *bus) Credentials(_ context.Context, node string, asConsumer, _ []compos
 			return nil, nil, fmt.Errorf("%s is not on %s: neither assigned there nor required by a module there", k.ConsumerModule, node)
 		}
 	}
-	return nil, nil, nil
+	var out []compose.Credential
+	var issued []compose.Issued
+	for _, k := range append(append([]compose.CredentialKey{}, asConsumer...), asProvider...) {
+		if b.held {
+			out = append(out, compose.Credential{Provision: k.Provision, Consumer: k.Consumer, ConsumerModule: k.ConsumerModule,
+				Provider: k.Provider, Local: k.Local, State: compose.CredentialHeld, Sealed: `"box"`})
+			issued = append(issued, compose.Issued{Provision: k.Provision, Consumer: k.Consumer, ConsumerModule: k.ConsumerModule,
+				Provider: k.Provider, Local: k.Local, ForProvider: `"box"`})
+		}
+	}
+	return out, issued, nil
 }
 
 func (b *bus) Values(_ context.Context, node, module string) (map[string]any, error) {
@@ -216,6 +230,14 @@ func TestInput(t *testing.T) {
 		wj, _ := json.MarshalIndent(want, "", " ")
 		t.Fatalf("Input from the bus differs from the store's:\n got %s\nwant %s", gj, wj)
 	}
+	// L3 s8 (ADR 0550 §2): with the vault's authority published, the mesh's authority is the bundle of the controller's
+	// and the vault's; with none, the controller's alone, as above.
+	signing := mk()
+	signing.vaultAuthority = "the vault's certificate"
+	if bundled, err := Input(ctx, signing, Mesh{}, Scope{Node: "laptop"}); err != nil ||
+		bundled.Authority != "the mesh's certificate\nthe vault's certificate\n" {
+		t.Errorf("the authority with the vault's published: %q, %v", bundled.Authority, err)
+	}
 	if !reflect.DeepEqual(b.valuesRead, []string{"laptop." + overlay.Name, "laptop.xterm", "laptop.media"}) {
 		t.Errorf("laptop read config values %v; a node reads its own slice alone", b.valuesRead)
 	}

go/compose/input.go

@@ -210,6 +210,12 @@ type Node struct {
 	// (RunsOwn), folded or leaving the fold, is carried there as it runs, whatever its manifest names, so the node's own
 	// never drops it.
 	Held map[string]bool
+	// RunsTools is, by module, the tools bundles the node's runtime serves of it as it runs (ToolsRunning of what the
+	// node runs); nil when not known. A module composed as what runs of it (its Stub or Carried: held, or folded at a
+	// build of the old form) contributes these to the runtime, never its manifest's: a manifest no build resolved has no
+	// bundles, and a held module's new build's bundles are not delivered (issue 1126, 2026-10-29: shanks's runtime lost
+	// the folded systemd-resolved, novox's the folded nats).
+	RunsTools map[string][]catalogue.Bundle
 }
 
 // Place is where a node is, as its placement says (inv.Overlay).

go/compose/judge/judge.go

@@ -258,9 +258,13 @@ func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
 		if held := v.Answers[n].Held; len(held) > 0 {
 			var names []string
 			for _, h := range held {
-				names = append(names, h.Module)
+				today := h.Today
+				if today == "" {
+					today = "held"
+				}
+				names = append(names, h.Module+" ("+today+")")
 			}
-			fmt.Fprintf(&b, "; stays held as today: %s", strings.Join(names, ", "))
+			fmt.Fprintf(&b, "; stays as today: %s", strings.Join(names, ", "))
 		}
 	}
 	return b.String()

go/compose/judge/judge_test.go

@@ -79,7 +79,7 @@ func TestJudge(t *testing.T) {
 				t.Errorf("the difference is named %q", got)
 			}
 		}
-		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays held as today: spiegel") {
+		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays as today: spiegel (held)") {
 			t.Errorf("%s: the brief does not show it: %s", row.name, Brief(q, v))
 		}
 		if row.marked != "" && (!slices.Contains(v.Unintended["anchor"], row.marked) || !strings.Contains(Brief(q, v), "not computed: "+row.marked)) {

go/delivery/assigner_test.go

@@ -298,6 +298,25 @@ func TestControllerGrant(t *testing.T) {
 	if _, err := EncodeControllerGrant(ControllerGrant{Accounts: []string{""}}); err == nil {
 		t.Errorf("a grant naming an empty account was accepted")
 	}
+	// The grants part's keys are the controller's: the same key round-trips; the source is the part's bucket only for a
+	// handed-away lease (issue 774).
+	if pk, err := PartGrantKey("mesh-delivery-assigner", fp); err != nil || pk != key {
+		t.Errorf("PartGrantKey = %q, %v, want the controller's %q", pk, err, key)
+	}
+	if m, f, err := ParsePartGrantKey(key); err != nil || m != "mesh-delivery-assigner" || f != fp {
+		t.Errorf("ParsePartGrantKey = %q, %q, %v", m, f, err)
+	}
+	for _, c := range []struct {
+		away         bool
+		bucket, read string
+	}{
+		{false, "mesh-controller_grants", "mesh-controller.grants"},
+		{true, "mesh-grants_grants", "mesh-grants.grants"},
+	} {
+		if b, r := GrantSource(c.away); b != c.bucket || r != c.read {
+			t.Errorf("GrantSource(%v) = %q, %q, want %q, %q", c.away, b, r, c.bucket, c.read)
+		}
+	}
 	g := ControllerGrant{Accounts: []string{"ace.mesh-build-go", "shanks.mesh-mail.reader"}}
 	for _, c := range []struct {
 		g            ControllerGrant

go/delivery/buildrun/standing.go

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

go/delivery/buildrun/standing_test.go

@@ -0,0 +1,238 @@
+package buildrun
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+func gateReport(t *testing.T, node, version string, at time.Time) (string, []byte) {
+	t.Helper()
+	key, err := delivery.ToolchainKey(node, "typescript")
+	if err != nil {
+		t.Fatal(err)
+	}
+	value, err := delivery.EncodeToolchain(delivery.Toolchain{Language: "typescript", Version: version, Recipe: "f59571cf4be75adf", At: at})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return key, value
+}
+
+// placing is a value of the state `placement` placing modules on node.
+func placing(t *testing.T, node string, modules ...string) (string, []byte) {
+	t.Helper()
+	p := delivery.Placement{Node: node}
+	for _, m := range modules {
+		p.Modules = append(p.Modules, delivery.PlacedModule{Module: m})
+	}
+	key, err := delivery.PlacementKey(node)
+	if err != nil {
+		t.Fatal(err)
+	}
+	value, err := delivery.EncodePlacement(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return key, value
+}
+
+func agreedOf(set *ToolchainSet) (string, string) {
+	tc, none := delivery.AgreedToolchain(set.Entries("typescript"))
+	return tc.Version, none
+}
+
+// Issue 1940, the gate over the catalogue's placement (issue 774, ADR 0549 §3): a build node's report counts only while
+// the placement places its build module on its node, and only once written since; before the placement is settled, and
+// while no node's placement is held, every report counts. The live cases: mesh-build-node taken off ace left
+// ace.typescript at v26.12.0 against v26.12.1 on the three others; put on ace again, its report of 2026-10-23 06:29 came
+// back before the module ran there.
+func TestToolchainGate(t *testing.T) {
+	old := time.Date(2026, 10, 23, 6, 29, 18, 0, time.UTC)     // ace's report from its earlier run
+	placed := time.Date(2026, 10, 25, 19, 56, 45, 0, time.UTC) // mesh-build-node placed on ace again
+	three := []string{"g14", "novox", "shanks"}
+	start := func(t *testing.T, seeded bool) (*ToolchainGate, *ToolchainSet, *[]string) {
+		set := &ToolchainSet{}
+		said := &[]string{}
+		gate := NewToolchainGate([]string{GoBuildModule, NodeBuildModule}, set.Put, func(f string, a ...any) { *said = append(*said, fmt.Sprintf(f, a...)) })
+		for _, node := range three {
+			if seeded {
+				key, value := placing(t, node, NodeBuildModule)
+				gate.Placement(key, value, false, old.Add(-time.Hour))
+			}
+			key, value := gateReport(t, node, "v26.12.1", placed.Add(time.Minute))
+			gate.Toolchain(NodeBuildModule, key, value, false)
+		}
+		return gate, set, said
+	}
+
+	t.Run("not placed on ace: its report is no builder's", func(t *testing.T) {
+		gate, set, said := start(t, true)
+		key, value := gateReport(t, "ace", "v26.12.0", old)
+		gate.Toolchain(NodeBuildModule, key, value, false)
+		if _, none := agreedOf(set); !strings.HasPrefix(none, "builders disagree") {
+			t.Fatalf("before the placement is settled every report counts; got %q", none)
+		}
+		k, v := placing(t, "ace", GoBuildModule) // another build module on ace: no matter
+		gate.Placement(k, v, false, old)
+		if !gate.Settled() {
+			t.Fatal("settling left ace's report out, so what was passed on changed")
+		}
+		if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+			t.Fatalf("the placed nodes agree on v26.12.1; got %q, %q", v, none)
+		}
+		if len(*said) != 1 || !strings.Contains((*said)[0], "does not place mesh-build-node on ace") {
+			t.Fatalf("ace's report is said left out once; said %q", *said)
+		}
+		if gate.Toolchain(NodeBuildModule, key, value, false) {
+			t.Fatal("a report of a node not placed changed what was passed on")
+		}
+		// Placed on ace with a report written since: it counts, and the builders really disagree.
+		k, v = placing(t, "ace", GoBuildModule, NodeBuildModule)
+		gate.Placement(k, v, false, old.Add(-time.Minute))
+		if _, none := agreedOf(set); !strings.HasPrefix(none, "builders disagree: v26.12.0 recipe f59571cf4be75adf on ace") {
+			t.Fatalf("builders that run different versions still disagree; got %q", none)
+		}
+		// Taken off ace again (its key deleted): its report goes again.
+		if !gate.Placement(k, nil, true, placed) {
+			t.Fatal("taking ace's placement away passed nothing on")
+		}
+		if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+			t.Fatalf("got %q, %q", v, none)
+		}
+		// A report deleted from the bucket goes whether its node is placed or not.
+		key, _ = gateReport(t, "g14", "v26.12.1", placed)
+		if !gate.Toolchain(NodeBuildModule, key, nil, true) || len(set.Entries("typescript")) != 2 {
+			t.Fatalf("deleting g14's report: %d entries left, want novox and shanks", len(set.Entries("typescript")))
+		}
+	})
+
+	for _, c := range []struct {
+		name   string
+		at     time.Time // when ace wrote its report
+		counts bool
+	}{
+		{"a report left before the placement", old, false},
+		{"a report written since the placement", placed.Add(30 * time.Second), true},
+	} {
+		t.Run(c.name, func(t *testing.T) {
+			gate, set, said := start(t, true)
+			k, v := placing(t, "ace") // ace's key, first heard placing nothing
+			gate.Placement(k, v, false, old.Add(-time.Hour))
+			gate.Settled()
+			k, v = placing(t, "ace", NodeBuildModule)
+			if gate.Placement(k, v, false, placed) {
+				t.Fatal("a placement with no report passed something on")
+			}
+			key, value := gateReport(t, "ace", "v26.12.0", c.at)
+			if got := gate.Toolchain(NodeBuildModule, key, value, false); got != c.counts {
+				t.Fatalf("ace's report passed on: %v, want %v", got, c.counts)
+			}
+			// ace's placement written again with another module beside: its standing does not move, nothing is said again.
+			k, v = placing(t, "ace", GoBuildModule, NodeBuildModule)
+			if gate.Placement(k, v, false, placed.Add(time.Minute)) {
+				t.Fatal("the same placement of mesh-build-node changed what was passed on")
+			}
+			if c.counts {
+				return
+			}
+			if v, none := agreedOf(set); v != "v26.12.1" || none != "" {
+				t.Fatalf("ace's left report is no builder's; got %q, %q", v, none)
+			}
+			if len(*said) != 1 || !strings.Contains((*said)[0], "before mesh-build-node was placed on ace at 2026-10-25T19:56:45Z") {
+				t.Fatalf("said %q, want once why ace's report is left out", *said)
+			}
+			key, value = gateReport(t, "ace", "v26.12.1", placed.Add(time.Minute))
+			if !gate.Toolchain(NodeBuildModule, key, value, false) || len(set.Entries("typescript")) != 4 {
+				t.Fatal("ace's new report was not passed on")
+			}
+		})
+	}
+
+	t.Run("no placement held: every report counts", func(t *testing.T) {
+		gate, set, _ := start(t, false)
+		key, value := gateReport(t, "ace", "v26.12.0", old)
+		gate.Toolchain(NodeBuildModule, key, value, false)
+		gate.Settled()
+		if n := len(set.Entries("typescript")); n != 4 {
+			t.Fatalf("before the first placement file every report counts; got %d", n)
+		}
+		k, v := placing(t, "g14", NodeBuildModule)
+		if !gate.Placement(k, v, false, old.Add(-time.Hour)) || len(set.Entries("typescript")) != 1 {
+			t.Fatalf("the first placement leaves every node it does not place out; got %d", len(set.Entries("typescript")))
+		}
+		if !gate.Placement(k, nil, true, placed) || len(set.Entries("typescript")) != 4 {
+			t.Fatal("the last placement gone: every report counts again")
+		}
+	})
+
+	t.Run("the history: a module in the first revision heard of a key stands since before it", func(t *testing.T) {
+		p := delivery.NewPlaced()
+		k, v := placing(t, "ace", NodeBuildModule)
+		p.Put(k, v, false, old)
+		k2, v2 := placing(t, "g14")
+		p.Put(k2, v2, false, old)
+		k2, v2 = placing(t, "g14", NodeBuildModule)
+		if _, changed, _ := p.Put(k2, v2, false, placed); strings.Join(changed, ",") != NodeBuildModule {
+			t.Errorf("a module placed says changed %v", changed)
+		}
+		if _, _, err := p.Put("placement.novox", []byte("not json"), false, old); err == nil {
+			t.Error("a value that does not read was not said")
+		}
+		if s, ok := p.Since("ace", NodeBuildModule); !ok || !s.IsZero() {
+			t.Errorf("ace's module stands since %v, %v; want the zero time", s, ok)
+		}
+		if s, ok := p.Since("g14", NodeBuildModule); !ok || !s.Equal(placed) {
+			t.Errorf("g14's module stands since %v, %v; want the revision that placed it", s, ok)
+		}
+		if got := p.PlacedNodes(NodeBuildModule); strings.Join(got, ",") != "ace,g14" || len(p.ByNode()) != 2 || !p.Seeded() {
+			t.Errorf("PlacedNodes = %v, ByNode = %v", got, p.ByNode())
+		}
+	})
+
+	t.Run("a placement the bus refuses is said, and the part goes on", func(t *testing.T) {
+		var logs bytes.Buffer
+		logger := log.New(&logs, "", 0)
+		refused := errors.New("nats: permissions violation for publish to $JS.API.CONSUMER.CREATE.KV_mesh-delivery-assigner_placement")
+		gate, _, _ := start(t, false)
+		for _, bus := range []refusingBus{{err: refused}, {refuseOpen: true, err: refused}} {
+			if _, err := FollowPlacement(context.Background(), bus, gate, func(context.Context) {}, logger.Printf); err != nil {
+				t.Errorf("a refused placement stopped the start: %v", err)
+			}
+		}
+		if !strings.Contains(logs.String(), "cannot be watched") || !strings.Contains(logs.String(), "cannot be read") {
+			t.Errorf("the refusals were not said: %q", logs.String())
+		}
+	})
+}
+
+// refusingBus is a bus that refuses: every open (refuseOpen), or every watch of a bucket it opens, with err.
+type refusingBus struct {
+	refuseOpen bool
+	err        error
+}
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) {
+	if r.refuseOpen {
+		return nil, r.err
+	}
+	return refusedWatch{err: r.err}, nil
+}
+
+type refusedWatch struct {
+	jetstream.KeyValue
+	err error
+}
+
+func (r refusedWatch) WatchAll(context.Context, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
+}

go/delivery/buildrun/toolchains_test.go

@@ -35,10 +35,8 @@ func TestToolchainSetKeepsEachNodesEntryByLanguageAndSaysWhenOneChanged(t *testi
 	if !s.Put(GoBuildModule, "ace.go", nil, true) || len(s.Entries("go")) != 1 {
 		t.Error("a delete did not remove the node's entry")
 	}
-}
-
-func TestToolchainSetLeavesOutWhatIsNotAToolchainOfTheModulesLanguage(t *testing.T) { // 1607/AC6
-	var s ToolchainSet
+	// What is not a toolchain of the module's language is left out.
+	s = ToolchainSet{}
 	if s.Put(GoBuildModule, "novox.typescript", tcValue(t, "typescript", "x"), false) {
 		t.Error("a typescript toolchain in the go build module's bucket counted")
 	}

go/delivery/composed_signature_test.go

@@ -3,9 +3,12 @@ package delivery
 import (
 	"crypto/ed25519"
 	"crypto/rand"
+	"crypto/x509"
 	"encoding/json"
+	"encoding/pem"
 	"strings"
 	"testing"
+	"time"
 )
 
 func aSigningKey(t *testing.T) (ed25519.PublicKey, ed25519.PrivateKey) {
@@ -100,4 +103,88 @@ func TestACompositionIsSignedByAKeptKey(t *testing.T) {
 	if _, err := SignComposedBy(c, pub, func(m []byte) ([]byte, error) { return ed25519.Sign(other, m), nil }); err == nil {
 		t.Errorf("a signature by another key than the one named was accepted")
 	}
+
+	// L3 s1 (ADR 0550 §2): a message the vault or the controller signed under a kind's context verifies against the
+	// signers a node trusts and names which; an unknown key and another kind's context are refused.
+	vaultPub, vault := aSigningKey(t)
+	controllerPub, controller := aSigningKey(t)
+	trusted := []Signer{{Name: SignerController, Key: controllerPub}, {Name: SignerVault, Key: vaultPub}}
+	enrol, _ := SignContext(KindEnrolment)
+	certCtx, _ := SignContext(KindNodeCertificate)
+	msg := []byte("the reply")
+	for _, row := range []struct {
+		name    string
+		key     ed25519.PrivateKey
+		signed  string
+		checked string
+		want    string
+	}{
+		{"the vault's key verifies", vault, enrol, enrol, SignerVault},
+		{"the controller's key verifies", controller, enrol, enrol, SignerController},
+		{"an unknown key is refused", other, enrol, enrol, ""},
+		{"the wrong context is refused", vault, certCtx, enrol, ""},
+	} {
+		got, err := VerifyBy(trusted, row.checked, msg, SignMessage(row.key, row.signed, msg))
+		if row.want == "" && err == nil {
+			t.Errorf("%s: verified as %s", row.name, got.Name)
+		}
+		if row.want != "" && (err != nil || got.Name != row.want) {
+			t.Errorf("%s: %+v, %v", row.name, got.Name, err)
+		}
+	}
+	if _, err := SignContext("hand-over"); err == nil {
+		t.Error("a kind the vault does not sign has a context")
+	}
+	// The signers' key reads back only when its fingerprint is its key's, and what a node trusts names both holders.
+	k := NewSignerKey(vaultPub, time.Unix(0, 0))
+	raw, _ := json.Marshal(k)
+	if back, err := DecodeSignerKey(raw); err != nil || back.Fingerprint != SignerFingerprint(vaultPub) {
+		t.Errorf("the signers' key: %+v, %v", back, err)
+	}
+	k.Fingerprint = SignerFingerprint(controllerPub)
+	if raw, _ := json.Marshal(k); true {
+		if _, err := DecodeSignerKey(raw); err == nil {
+			t.Error("a signers' key naming another fingerprint was taken")
+		}
+	}
+	if got := Trusts(trusted, nil); len(got) != 2 || !TrustsKey(got, SignerVault, SignerFingerprint(vaultPub)) ||
+		!TrustsKey(got, SignerController, SignerFingerprint(controllerPub)) {
+		t.Errorf("trusts: %v", got)
+	}
+	// A certificate the vault's authority signs for a node's name and serving key checks against a bundle holding that
+	// authority, and not for another name, another key, or against the controller's alone; a bundle given again adds no
+	// certificate twice.
+	authority := func(pub ed25519.PublicKey, priv ed25519.PrivateKey) string {
+		tpl := AuthorityTemplate(pub, time.Now().Add(-time.Hour))
+		der, err := x509.CreateCertificate(nil, tpl, tpl, pub, priv)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return string(pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: der}))
+	}
+	vaultCA, controllerCA := authority(vaultPub, vault), authority(controllerPub, controller)
+	parent, _ := ParseCertificate(vaultCA)
+	serving, _ := aSigningKey(t)
+	der, err := x509.CreateCertificate(nil, NodeCertificateTemplate("ace.internal", serving, time.Now().Add(-time.Hour)), parent, serving, vault)
+	if err != nil {
+		t.Fatal(err)
+	}
+	leaf := string(pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: der}))
+	bundle := AuthorityBundle(controllerCA, AuthorityBundle(controllerCA, vaultCA))
+	if n := strings.Count(bundle, "BEGIN CERTIFICATE"); n != 2 {
+		t.Errorf("the bundle holds %d certificates, want 2", n)
+	}
+	now := time.Now()
+	if err := CheckNodeCertificate(leaf, []string{bundle}, "ace.internal", serving, now); err != nil {
+		t.Errorf("the vault's certificate does not check: %v", err)
+	}
+	for name, err := range map[string]error{
+		"another name":           CheckNodeCertificate(leaf, []string{vaultCA}, "g14.internal", serving, now),
+		"another key":            CheckNodeCertificate(leaf, []string{vaultCA}, "ace.internal", controllerPub, now),
+		"the controller's alone": CheckNodeCertificate(leaf, []string{controllerCA}, "ace.internal", serving, now),
+	} {
+		if err == nil {
+			t.Errorf("%s: checked", name)
+		}
+	}
 }

go/delivery/grants.go

@@ -90,3 +90,39 @@ func (g ControllerGrant) NamesNode(node, module string) bool {
 	}
 	return false
 }
+
+// **The grants part's grants** (novox/hq ADR 0547 §4, §5, ADR 0561 §2, §6; issue 774). The grants part writes the same
+// keys, with the same value, into its own state `grants` (the bucket PartGrantsBucket), beside the controller's: first in
+// shadow, which nobody reads, so a tool can compare the two before anything switches. The assigner reads the part's keys
+// only once the controller's lease is handed away (GrantSource), and the controller's until then.
+const (
+	// PartGrantsState is the grants part's state of issued credentials by fingerprint, as its manifest names it.
+	PartGrantsState = "grants"
+	// PartGrantsBucket is that state's bucket, `<owner module>_<name>`.
+	PartGrantsBucket = "mesh-grants_" + PartGrantsState
+	// PartGrantsRead is that state as a reader names it in `reads`.
+	PartGrantsRead = "mesh-grants." + PartGrantsState
+	// PartGrantsHistory is the revisions the bucket keeps per key.
+	PartGrantsHistory = ControllerGrantsHistory
+)
+
+// PartGrantKey is the key, in PartGrantsBucket, of a module's credential issued for a fingerprint: the layout of the
+// controller's key (ControllerGrantKey), so a key of one is the key of the other and a compare is by key.
+func PartGrantKey(module, fingerprint string) (string, error) {
+	return ControllerGrantKey(module, fingerprint)
+}
+
+// ParsePartGrantKey is the inverse of PartGrantKey.
+func ParsePartGrantKey(key string) (module, fingerprint string, err error) {
+	return ParseControllerGrantKey(key)
+}
+
+// GrantSource names the bucket the assigner reads grants from, and the `reads` name that grants it: the grants part's
+// once the controller's lease is handed away (buscompose.LeaseHandedAway, which refuses every other value of the lease,
+// an unreadable one included), the controller's in every other case.
+func GrantSource(leaseHandedAway bool) (bucket, read string) {
+	if leaseHandedAway {
+		return PartGrantsBucket, PartGrantsRead
+	}
+	return ControllerGrantsBucket, "mesh-controller.grants"
+}

go/delivery/judge.go

@@ -3,6 +3,7 @@ package delivery
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"path"
 	"sort"
 	"strings"
@@ -84,9 +85,6 @@ func judged(from, to Composed) (Judgement, string) {
 	if ids := changedOf(before, after, func(kind string) bool { return kind == string(declaration.TypeContainer) }); len(ids) > 0 {
 		return JudgedRecreates, "it recreates " + strings.Join(ids, ", ")
 	}
-	if from.Data != to.Data {
-		return JudgedMovesData, "its data declaration changes"
-	}
 	places := dataPlaces(before, after)
 	held := func(kind string) bool {
 		return kind == string(declaration.TypeDirectory) || kind == string(declaration.TypeFile)
@@ -104,9 +102,20 @@ func judged(from, to Composed) (Judgement, string) {
 	if to.Data || from.Data {
 		moved = append(moved, changedOf(before, after, func(kind string) bool { return kind == string(declaration.TypeProcess) })...)
 	}
+	// A data flag that differs is no move of data by itself: data moves only when a data item does (issue 1126, 2026-10-29:
+	// a running composition read back from the kept declaration carries no flag, and mongodb's toolchain move asked a yes for
+	// moving its data). It is said loudly in the words, and never hides an item that moved.
 	if len(moved) > 0 {
 		sort.Strings(moved)
-		return JudgedMovesData, "it changes where its data is kept: " + strings.Join(moved, ", ")
+		words := "it changes where its data is kept: " + strings.Join(moved, ", ")
+		if from.Data != to.Data {
+			words += fmt.Sprintf("; its data flag differs too (running %v, composed %v)", from.Data, to.Data)
+		}
+		return JudgedMovesData, words
+	}
+	if from.Data != to.Data {
+		return JudgedNeither, fmt.Sprintf("it recreates no container and moves no data; WARNING: its data flag differs "+
+			"(running %v, composed %v) while no data item does, so one side's flag is wrong", from.Data, to.Data)
 	}
 	return JudgedNeither, "it recreates no container and moves no data"
 }

go/delivery/judge_test.go

@@ -48,7 +48,8 @@ func TestJudgeMove(t *testing.T) {
 		{"a container gone", mail('a', true, container, spool), mail('b', true, spool), JudgedRecreates, false},
 		{"its spool moved", mail('a', true, container, spool), mail('b', true, container, spoolMoved), JudgedMovesData, false},
 		{"a file in its spool", mail('a', true, container, spool, config), mail('b', true, container, spool, config2), JudgedMovesData, false},
-		{"its data declaration", mail('a', false, container, spool), mail('b', true, container, spool), JudgedMovesData, false},
+		{"its data flag alone", mail('a', false, container, spool), mail('b', true, container, spool), JudgedNeither, false},
+		{"its data flag and its spool", mail('a', false, container, spool), mail('b', true, container, spoolMoved), JudgedMovesData, false},
 		{"a process of a module with data", mail('a', true, spool, process), mail('b', true, spool, process2), JudgedMovesData, false},
 		{"a process of a module without", mail('a', false, process), mail('b', false, process2), JudgedNeither, false},
 		{"its tools only", mail('a', true, container, spool, tools), mail('b', true, container, spool, tools2), JudgedNeither, false},
@@ -61,6 +62,9 @@ func TestJudgeMove(t *testing.T) {
 		if got.Judgement != c.want || got.UserListOnly != c.userList || got.Words == "" {
 			t.Errorf("%s: %+v, want %s (user list only %v)", c.name, got, c.want, c.userList)
 		}
+		if strings.Contains(c.name, "data flag alone") && !strings.Contains(got.Words, "WARNING: its data flag differs") {
+			t.Errorf("%s: the flag's difference is not said: %q", c.name, got.Words)
+		}
 	}
 	if got := JudgeMove(nil, Composed{Node: "ace"}); got.Judgement != JudgedNeither {
 		t.Errorf("the node's own composition: %+v", got)

go/delivery/noderecord.go

@@ -55,6 +55,10 @@ type NodeRecord struct {
 	// Authority is the mesh's own certificate as this machine holds it (public): the one its declaration last wrote where
 	// a module asked for it. A node composing its own composes a certificate with it (compose.Input.Authority).
 	Authority string `json:"authority,omitempty"`
+	// Trusts is what this machine trusts a mesh signature from now (Trusts in signers.go, ADR 0550 §2): the controller's
+	// key until the lease is handed away, and the vault's key and authority once it reads them from `signers`. The gate
+	// before the lease write reads every node's from the bus.
+	Trusts []string `json:"trusts,omitempty"`
 }
 
 func (r NodeRecord) check() error {

go/delivery/noderecord_test.go

@@ -18,7 +18,7 @@ var secretNamed = regexp.MustCompile(`(?i)(secret|passw|token|api[-_]?key|privat
 func TestNodeRecord(t *testing.T) {
 	hub := NodeRecord{Node: "novox", TunnelKey: "k", Capabilities: []string{"docker"}, SealingKey: "age1x", ServingKey: "pub",
 		Certificate: "cert", OutwardLinks: []string{"eth0"}, Networks: []catalogue.AttachedNetwork{{Link: "eth0", Network: "192.0.2.0/24"}},
-		NetworksSaid: true, Contract: 3}
+		NetworksSaid: true, Contract: 3, Trusts: []string{"controller key sha256:aa", "vault key sha256:bb"}}
 	raw, err := EncodeNodeRecord(hub)
 	if err != nil {
 		t.Fatal(err)

go/delivery/placed.go

@@ -0,0 +1,126 @@
+package delivery
+
+import (
+	"fmt"
+	"maps"
+	"slices"
+	"sync"
+	"time"
+)
+
+// Placed is where the placement (the seat mesh-placement's state `placement`, held by the assigner; ADR 0567, ADR 0549 §3) places each module, and since when:
+// the one reader of that state for every part that asks "does module stand on node" (issue 774, design 47's third
+// milestone), in place of each part reading the controller's assignments (`mesh-controller_assignments`, which goes
+// with the controller's lease, ADR 0549 §6).
+//
+// Its input is the state's revisions in the order the bus wrote them, as a watch with the history (jetstream's
+// IncludeHistory) hands them: Put takes each. A module stands since the revision of its node's key that first named it
+// in an unbroken run. A module in the first revision heard of a key stands since the zero time: that revision is the
+// key's first (the seed of ADR 0549 §4 placed what already ran there) or the oldest the bus still keeps
+// (PlacementHistory), and either way the module may have run there before it. A key's value that does not read places
+// nothing on its node, and Put says why.
+//
+// Safe for use from a watch and from a reader at once.
+type Placed struct {
+	mu    sync.Mutex
+	since map[string]map[string]time.Time // node -> module -> since when it stands
+	heard map[string]bool                 // the nodes whose key was heard at all
+}
+
+// NewPlaced is a Placed that holds no placement yet.
+func NewPlaced() *Placed {
+	return &Placed{since: map[string]map[string]time.Time{}, heard: map[string]bool{}}
+}
+
+// Put takes one revision of a key of the state `placement` (its value, whether it is a delete, and when the bus wrote
+// it). It answers the node the key is of and the modules whose standing on it changed (placed or removed), in name
+// order, and an error for a key or a value that does not read (the node then places nothing).
+func (p *Placed) Put(key string, value []byte, deleted bool, at time.Time) (node string, changed []string, err error) {
+	node, err = ParsePlacementKey(key)
+	if err != nil {
+		return "", nil, err
+	}
+	now := map[string]bool{}
+	if !deleted {
+		pl, derr := DecodePlacement(value)
+		switch {
+		case derr != nil:
+			err = fmt.Errorf("the placement of %s does not read, so it places nothing there: %w", node, derr)
+		case pl.Node != node:
+			err = fmt.Errorf("the placement under %s names the node %q, so it places nothing there", key, pl.Node)
+		default:
+			for _, m := range pl.Assigned() {
+				now[m] = true
+			}
+		}
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if !p.heard[node] {
+		p.heard[node] = true
+		at = time.Time{}
+	}
+	was := p.since[node]
+	next := map[string]time.Time{}
+	for m := range now {
+		if s, ok := was[m]; ok {
+			next[m] = s
+		} else {
+			next[m] = at
+			changed = append(changed, m)
+		}
+	}
+	for m := range was {
+		if !now[m] {
+			changed = append(changed, m)
+		}
+	}
+	if len(next) == 0 {
+		delete(p.since, node)
+	} else {
+		p.since[node] = next
+	}
+	slices.Sort(changed)
+	return node, changed, err
+}
+
+// Seeded says some node's placement is held: before the assigner's adopt writes the first placement nothing is placed,
+// and a reader keeps what it did before (ADR 0549 §5).
+func (p *Placed) Seeded() bool {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return len(p.since) > 0
+}
+
+// Since says whether module stands on node, and since when (the zero time: since before the revisions kept).
+func (p *Placed) Since(node, module string) (time.Time, bool) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	s, ok := p.since[node][module]
+	return s, ok
+}
+
+// PlacedNodes is every node module is placed on, in name order.
+func (p *Placed) PlacedNodes(module string) []string {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	var out []string
+	for node, mods := range p.since {
+		if _, ok := mods[module]; ok {
+			out = append(out, node)
+		}
+	}
+	slices.Sort(out)
+	return out
+}
+
+// ByNode is, by node, the modules placed on it in name order.
+func (p *Placed) ByNode() map[string][]string {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	out := make(map[string][]string, len(p.since))
+	for node, mods := range p.since {
+		out[node] = slices.Sorted(maps.Keys(mods))
+	}
+	return out
+}

go/delivery/placement_candidate.go

@@ -190,10 +190,13 @@ type ModuleAdded struct {
 	Unissued []string `json:"unissued,omitempty"`
 }
 
-// ModuleRefused is a value missing for a module the node runs, in the words the composition stood in for it with.
+// ModuleRefused is a value missing for a module the node runs, in the words the composition stood in for it with. Today,
+// in CandidateAnswer.Held, is how the node keeps it today (held, failed, runs a build of the old form, held behind
+// another), which the candidate keeps.
 type ModuleRefused struct {
 	Module string `json:"module"`
 	Why    string `json:"why"`
+	Today  string `json:"today,omitempty"`
 }
 
 // VerdictOf is the verdict of an answer's lists: refused on any refusal, differs on any difference, addition or

go/delivery/signers.go

@@ -0,0 +1,350 @@
+package delivery
+
+import (
+	"crypto/ed25519"
+	"crypto/sha256"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"math/big"
+	"slices"
+	"strings"
+	"time"
+)
+
+// **The vault signs** (novox/hq ADR 0550 §2; design 47's L3 item d). The vault makes an ed25519 signing key and an x509
+// authority once, keeps both as its own secrets with their operator copies, and publishes their public halves in its
+// state `signers`, which only the vault writes and every node principal and composing part reads. Its verb `sign` signs a
+// node's certificate for that node's own node-engine, from bus state alone (the name from the node's placement, the
+// serving key from its record), and says `signed` naming the caller, the kind, the node and the digest, never the key.
+//
+// A node trusts the vault's key through the bus grants alone (the lead's design limit, 2026-10-28): only the vault may
+// write `signers`, the same trust the wants and the placement rest on. Until the controller's lease is handed away the
+// node trusts the controller's key beside it; from then on the vault's alone (LeaseHandedAway). What a node trusts now
+// it states in its record, NodeRecord.Trusts, so the gate before the lease write reads it from the bus.
+
+const (
+	// VaultModule is the module holding the seat mesh-vault, whose state `signers` is.
+	VaultModule = "mesh-vault"
+	// SignersState is the vault's state of its public signing halves, and SignersBucket its bucket.
+	SignersState  = "signers"
+	SignersBucket = VaultModule + "_" + SignersState
+	// SignersRead is the state as a manifest's `reads` names it.
+	SignersRead = VaultModule + "." + SignersState
+	// SignersKeyKey holds the signing key's public half (SignerKey); SignersAuthorityKey the authority (SignerAuthority).
+	SignersKeyKey       = "key"
+	SignersAuthorityKey = "authority"
+
+	// SignVerb is the vault's verb that signs.
+	SignVerb = "sign"
+	// SignedEvent is what the vault says when it signed (Signed), on SignedSubject.
+	SignedEvent   = "signed"
+	SignedSubject = "mesh.mod." + VaultModule + ".event." + SignedEvent
+
+	// KindNodeCertificate is a node's certificate for its internal name, asked by that node's node-engine alone.
+	KindNodeCertificate = "node-certificate"
+	// KindEnrolment is an enrolment reply, signed under its own context; no caller is named until adoption's record
+	// (ADR 0561 §5).
+	KindEnrolment = "enrolment"
+	// KindAuthority is the vault's own authority certificate, which the vault signs for itself.
+	KindAuthority = "authority"
+
+	// SignerController and SignerVault name the two signers a node may trust.
+	SignerController = "controller"
+	SignerVault      = "vault"
+
+	// CertificateLife is how long a certificate the vault signs for a node lasts: the controller's ten years
+	// (identity.forever), renewed by asking again, never by a clock running out unseen.
+	CertificateLife = 10 * 365 * 24 * time.Hour
+)
+
+// SignKinds are the kinds `sign` knows.
+var SignKinds = []string{KindNodeCertificate, KindEnrolment, KindAuthority}
+
+// SignContext is the line a message of kind is signed after, so a signature made for one kind never verifies as
+// another's (as the composition's and the asks' contexts are kept apart).
+func SignContext(kind string) (string, error) {
+	if !slices.Contains(SignKinds, kind) {
+		return "", fmt.Errorf("delivery: %q is not a kind the vault signs (%s)", kind, strings.Join(SignKinds, ", "))
+	}
+	return "novox " + kind + " v1\n", nil
+}
+
+// SignerKey is the key `key` of `signers`: the vault's signing key's public half in standard base64, its fingerprint,
+// and when it was made.
+type SignerKey struct {
+	Key         string    `json:"key"`
+	Fingerprint string    `json:"fingerprint"`
+	Made        time.Time `json:"made"`
+}
+
+// SignerAuthority is the key `authority` of `signers`: the vault's authority certificate as PEM, its fingerprint, and
+// when it was made.
+type SignerAuthority struct {
+	Certificate string    `json:"certificate"`
+	Fingerprint string    `json:"fingerprint"`
+	Made        time.Time `json:"made"`
+}
+
+// SignerFingerprint is an ed25519 public key's fingerprint, `sha256:<hex>` of its 32 bytes.
+func SignerFingerprint(key ed25519.PublicKey) string {
+	sum := sha256.Sum256(key)
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// AuthorityFingerprint is an authority certificate's fingerprint, `sha256:<hex>` of its DER; refused when certificate is
+// not one PEM certificate.
+func AuthorityFingerprint(certificate string) (string, error) {
+	c, err := ParseCertificate(certificate)
+	if err != nil {
+		return "", err
+	}
+	sum := sha256.Sum256(c.Raw)
+	return "sha256:" + hex.EncodeToString(sum[:]), nil
+}
+
+// ParseCertificate is the first certificate of a PEM text.
+func ParseCertificate(text string) (*x509.Certificate, error) {
+	block, _ := pem.Decode([]byte(strings.TrimSpace(text)))
+	if block == nil || block.Type != "CERTIFICATE" {
+		return nil, errors.New("delivery: not a PEM certificate")
+	}
+	return x509.ParseCertificate(block.Bytes)
+}
+
+// NewSignerKey is the value of `key` for pub.
+func NewSignerKey(pub ed25519.PublicKey, made time.Time) SignerKey {
+	return SignerKey{Key: base64.StdEncoding.EncodeToString(pub), Fingerprint: SignerFingerprint(pub), Made: made.UTC()}
+}
+
+// PublicKey is k's key, checked: an ed25519 public key whose fingerprint is the one k names.
+func (k SignerKey) PublicKey() (ed25519.PublicKey, error) {
+	raw, err := base64.StdEncoding.DecodeString(k.Key)
+	if err != nil || len(raw) != ed25519.PublicKeySize {
+		return nil, errors.New("delivery: the signers' key is not an ed25519 public key in base64")
+	}
+	if fp := SignerFingerprint(raw); fp != k.Fingerprint {
+		return nil, fmt.Errorf("delivery: the signers' key has the fingerprint %s, and names %s", fp, k.Fingerprint)
+	}
+	return ed25519.PublicKey(raw), nil
+}
+
+// DecodeSignerKey reads the key `key` of `signers`, refused when it does not check.
+func DecodeSignerKey(raw []byte) (SignerKey, error) {
+	var k SignerKey
+	if err := json.Unmarshal(raw, &k); err != nil {
+		return SignerKey{}, fmt.Errorf("delivery: %s %s: %w", SignersRead, SignersKeyKey, err)
+	}
+	if _, err := k.PublicKey(); err != nil {
+		return SignerKey{}, err
+	}
+	return k, nil
+}
+
+// DecodeSignerAuthority reads the key `authority` of `signers`: one authority certificate (a CA that signs leaves
+// alone) whose fingerprint is the one named.
+func DecodeSignerAuthority(raw []byte) (SignerAuthority, error) {
+	var a SignerAuthority
+	if err := json.Unmarshal(raw, &a); err != nil {
+		return SignerAuthority{}, fmt.Errorf("delivery: %s %s: %w", SignersRead, SignersAuthorityKey, err)
+	}
+	c, err := ParseCertificate(a.Certificate)
+	if err != nil {
+		return SignerAuthority{}, err
+	}
+	if !c.IsCA {
+		return SignerAuthority{}, errors.New("delivery: the signers' authority is not an authority certificate")
+	}
+	if fp, _ := AuthorityFingerprint(a.Certificate); fp != a.Fingerprint {
+		return SignerAuthority{}, fmt.Errorf("delivery: the signers' authority has the fingerprint %s, and names %s", fp, a.Fingerprint)
+	}
+	return a, nil
+}
+
+// Signer is one key a node trusts, by who holds it (SignerController, SignerVault, or the operator's).
+type Signer struct {
+	Name string
+	Key  ed25519.PublicKey
+}
+
+// Fingerprint is the signer's key's fingerprint.
+func (s Signer) Fingerprint() string { return SignerFingerprint(s.Key) }
+
+// VerifyBy is the trusted signer whose key verifies sig over context and msg: refused when no trusted key does, saying
+// so, and when a key is not an ed25519 key. A signature made under another context never verifies.
+func VerifyBy(trusted []Signer, context string, msg, sig []byte) (Signer, error) {
+	if len(sig) != ed25519.SignatureSize {
+		return Signer{}, errors.New("delivery: not an ed25519 signature")
+	}
+	message := append([]byte(context), msg...)
+	for _, s := range trusted {
+		if len(s.Key) != ed25519.PublicKeySize {
+			continue
+		}
+		if ed25519.Verify(s.Key, message, sig) {
+			return s, nil
+		}
+	}
+	names := make([]string, 0, len(trusted))
+	for _, s := range trusted {
+		names = append(names, s.Name)
+	}
+	return Signer{}, fmt.Errorf("delivery: the signature verifies against no trusted key (%s)", strings.Join(names, ", "))
+}
+
+// SignMessage is sig over context and msg by key: what the vault's `sign` does for a kind whose bytes are given.
+func SignMessage(key ed25519.PrivateKey, context string, msg []byte) []byte {
+	return ed25519.Sign(key, append([]byte(context), msg...))
+}
+
+// Signed is the vault's `signed`: who asked, the kind, the node, and the sha256 digest of what was signed. Never a key.
+type Signed struct {
+	Caller string    `json:"caller"`
+	Kind   string    `json:"kind"`
+	Node   string    `json:"node,omitempty"`
+	Digest string    `json:"digest"`
+	Signer string    `json:"signer"`
+	At     time.Time `json:"at"`
+}
+
+// SignAnswer is what `sign` answers: for a node certificate the certificate as PEM and the authority that signed it,
+// for an enrolment the signature in base64; always the signer's fingerprint and the digest. Never a key's private half.
+type SignAnswer struct {
+	Kind        string `json:"kind"`
+	Node        string `json:"node,omitempty"`
+	Certificate string `json:"certificate,omitempty"`
+	Authority   string `json:"authority,omitempty"`
+	Signature   string `json:"signature,omitempty"`
+	Signer      string `json:"signer"`
+	Digest      string `json:"digest"`
+}
+
+// DigestOf is the digest a `signed` names: `sha256:<hex>` of the bytes signed.
+func DigestOf(b []byte) string {
+	sum := sha256.Sum256(b)
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// NodeCertificateTemplate is the certificate the vault signs for node's internal name, as the controller's authority
+// shaped it (identity.Certify): the name in the subject and the subject alternative names, server and client use, the
+// serial derived from the name and the key so the same ask gives the same certificate, and its life from notBefore.
+func NodeCertificateTemplate(name string, servingKey ed25519.PublicKey, notBefore time.Time) *x509.Certificate {
+	sum := sha256.Sum256(append([]byte(name+"\n"), servingKey...))
+	return &x509.Certificate{
+		SerialNumber: new(big.Int).SetBytes(sum[:16]),
+		Subject:      pkix.Name{CommonName: name},
+		DNSNames:     []string{name},
+		NotBefore:    notBefore.UTC().Truncate(time.Second),
+		NotAfter:     notBefore.UTC().Truncate(time.Second).Add(CertificateLife),
+		KeyUsage:     x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
+	}
+}
+
+// AuthorityTemplate is the vault's authority certificate for its key, made once: an authority that signs leaves and no
+// other authority, as the controller's.
+func AuthorityTemplate(key ed25519.PublicKey, made time.Time) *x509.Certificate {
+	sum := sha256.Sum256(append([]byte("authority\n"), key...))
+	return &x509.Certificate{
+		SerialNumber:          new(big.Int).SetBytes(sum[:16]),
+		Subject:               pkix.Name{CommonName: "the mesh's vault"},
+		NotBefore:             made.UTC().Truncate(time.Second),
+		NotAfter:              made.UTC().Truncate(time.Second).Add(2 * CertificateLife),
+		IsCA:                  true,
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+		MaxPathLen:            0,
+		MaxPathLenZero:        true,
+	}
+}
+
+// CheckNodeCertificate says why certificate is not a certificate of name for servingKey by one of the authorities, or
+// nil: a node uses it to tell whether its record holds a certificate from an authority it trusts, and another node to
+// check one the vault signed (ADR 0550 §2's live check).
+func CheckNodeCertificate(certificate string, authorities []string, name string, servingKey ed25519.PublicKey, at time.Time) error {
+	c, err := ParseCertificate(certificate)
+	if err != nil {
+		return err
+	}
+	pool := x509.NewCertPool()
+	for _, a := range authorities {
+		pool.AppendCertsFromPEM([]byte(a)) // a bundle is every certificate it holds
+	}
+	if _, err := c.Verify(x509.VerifyOptions{Roots: pool, DNSName: name, CurrentTime: at,
+		KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}}); err != nil {
+		return fmt.Errorf("delivery: the certificate of %s is not one a trusted authority signed for it: %w", name, err)
+	}
+	held, ok := c.PublicKey.(ed25519.PublicKey)
+	if !ok || !held.Equal(servingKey) {
+		return fmt.Errorf("delivery: the certificate of %s binds another key than the node serves with", name)
+	}
+	return nil
+}
+
+// AuthorityBundle is the authorities given as one PEM text, each certificate once, in the order given, blanks left out:
+// what a module asking for the mesh's authority is given once the vault signs beside the controller (ADR 0550 §2). An
+// authority given is split into its certificates, so a bundle given again (the one a node kept from its last
+// composition) adds nothing twice; a text that holds no PEM block is taken whole.
+func AuthorityBundle(authorities ...string) string {
+	var out []string
+	for _, a := range authorities {
+		for _, piece := range pemPieces(a) {
+			if !slices.Contains(out, piece) {
+				out = append(out, piece)
+			}
+		}
+	}
+	if len(out) == 0 {
+		return ""
+	}
+	return strings.Join(out, "\n") + "\n"
+}
+
+// pemPieces is each PEM block of text re-encoded, or the trimmed text whole when it holds none.
+func pemPieces(text string) []string {
+	text = strings.TrimSpace(text)
+	if text == "" {
+		return nil
+	}
+	var out []string
+	rest := []byte(text)
+	for {
+		block, more := pem.Decode(rest)
+		if block == nil {
+			break
+		}
+		out = append(out, strings.TrimSpace(string(pem.EncodeToMemory(block))))
+		rest = more
+	}
+	if len(out) == 0 {
+		return []string{text}
+	}
+	return out
+}
+
+// Trusts is what a node states it trusts now (NodeRecord.Trusts): `<who> key <fingerprint>` for each signer and
+// `<who> authority <fingerprint>` for each authority certificate, by who holds it, each once, sorted. The gate before the
+// lease write reads `vault key <fingerprint>` in every node's record.
+func Trusts(signers []Signer, authorities map[string]string) []string {
+	var out []string
+	for _, s := range signers {
+		if len(s.Key) == ed25519.PublicKeySize {
+			out = append(out, s.Name+" key "+s.Fingerprint())
+		}
+	}
+	for who, a := range authorities {
+		if fp, err := AuthorityFingerprint(a); err == nil {
+			out = append(out, who+" authority "+fp)
+		}
+	}
+	slices.Sort(out)
+	return slices.Compact(out)
+}
+
+// TrustsKey says whether trusts names the key with fingerprint fp held by who.
+func TrustsKey(trusts []string, who, fp string) bool { return slices.Contains(trusts, who+" key "+fp) }