Merge pull request 'plans --what-if: the plan a merge would produce, read before merging' (#205) from feat/plans-what-if into main

Given a repository and the files a branch changes (or the modules by name), plans answers with the tiers
the merge handler would produce — the modules those files touch, what packages their source, everything
reachable along the dependency relation — and what each tier does: built and sent to its machines, or
built and left because its policy records. Saved nowhere. On the seat as plans {repository, paths|modules}.

cmd/mesh-controller/adopting_test.go

@@ -109,10 +109,10 @@ var (
 
 func TestTakingAModuleNotOnTheNodeIsRefused(t *testing.T) {
 	open, _ := anAdoptedAnchor(t)
-	if _, err := take(t.Context(), open, "anchor", "nftables"); !errors.Is(err, inventory.ErrNotAssigned) {
+	if _, err := take(t.Context(), open, "anchor", "nftables", takeOptions{Yes: true}); !errors.Is(err, inventory.ErrNotAssigned) {
 		t.Fatalf("taking an unassigned module gave %v", err)
 	}
-	if _, err := take(t.Context(), open, "laptop", "network"); !errors.Is(err, inventory.ErrNotAdopted) {
+	if _, err := take(t.Context(), open, "laptop", "network", takeOptions{Yes: true}); !errors.Is(err, inventory.ErrNotAdopted) {
 		t.Fatalf("taking on a converged node gave %v", err)
 	}
 }
@@ -143,7 +143,7 @@ func TestTheFlipIsRefusedWhileAFoundContainerIsHeld(t *testing.T) {
 func TestTakingNamesWhatItReplaces(t *testing.T) {
 	open, _ := anAdoptedAnchor(t)
 	reportsHolding(t, open, heldContainer, heldFile)
-	said, err := take(t.Context(), open, "anchor", "hello-web")
+	said, err := take(t.Context(), open, "anchor", "hello-web", takeOptions{Yes: true})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -156,7 +156,7 @@ func TestTakingNamesWhatItReplaces(t *testing.T) {
 func TestConvergingPreviewsThenChangesAndAdoptingKeepsWhatWasTaken(t *testing.T) {
 	open, sent := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	reportsHolding(t, open, heldFile)
@@ -330,7 +330,7 @@ func digestIn(t *testing.T, preview string) string {
 func TestTheFlipActsOnlyOnThePreviewTheOperatorSaw(t *testing.T) {
 	open, sent := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	reportsHolding(t, open, heldFile)
@@ -396,7 +396,7 @@ func TestTheFlipActsOnlyOnThePreviewTheOperatorSaw(t *testing.T) {
 func TestTheFlipHoldsTheNodeWhileItSends(t *testing.T) {
 	open, _ := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	reportsHolding(t, open, heldFile)
@@ -441,7 +441,7 @@ func TestTheFlipHoldsTheNodeWhileItSends(t *testing.T) {
 func TestThePreviewNamesEveryHeldKind(t *testing.T) {
 	open, _ := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	since := time.Now()
@@ -484,7 +484,7 @@ func TestThePreviewNamesEveryHeldKind(t *testing.T) {
 func TestTheFlipIsRefusedOnAnAccountNamingNothingReachable(t *testing.T) {
 	open, sent := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	// Only a loopback listener: nothing off the machine, which is the same silence.
@@ -512,7 +512,7 @@ func TestTheFlipIsRefusedOnAnAccountNamingNothingReachable(t *testing.T) {
 func TestAssigningWaitsForWhateverIsConvergingTheNode(t *testing.T) {
 	open, _ := anAdoptedAnchor(t)
 	ctx := t.Context()
-	if _, err := take(ctx, open, "anchor", "hello-web"); err != nil {
+	if _, err := take(ctx, open, "anchor", "hello-web", takeOptions{Yes: true}); err != nil {
 		t.Fatal(err)
 	}
 	reportsHolding(t, open, heldFile)

cmd/mesh-controller/adoption.go

@@ -24,6 +24,11 @@ import (
 func showMode(ctx context.Context, inv *inventory.Inventory, node inventory.Node) error {
 	if !node.Adopted {
 		fmt.Printf("  mode              converged\n")
+		// A converged machine holds nothing, and can still run what nobody asked for
+		// (novox/hq ADR 0163): what it reports as strays is said whatever its mode.
+		if said, err := inv.AdoptionOf(ctx, node.Name); err == nil && len(said.Strays) > 0 {
+			showStrays(said.Strays)
+		}
 		return nil
 	}
 	fmt.Printf("  mode              adopted since %s\n",
@@ -62,11 +67,26 @@ func showMode(ctx context.Context, inv *inventory.Inventory, node inventory.Node
 		if h.Kept != "" {
 			fmt.Printf("  %-17s original kept at %s\n", "", h.Kept)
 		}
+		for _, f := range comparisonLines(h) {
+			fmt.Printf("  %-17s %s\n", "", f)
 		}
+	}
+	showStrays(said.Strays)
 	fmt.Printf("  as of             %s\n", said.At.Local().Format(time.DateTime))
 	return nil
 }
 
+// showStrays says what a machine runs that the mesh neither wrote nor holds (ADR 0163).
+func showStrays(strays []inventory.Stray) {
+	if len(strays) == 0 {
+		return
+	}
+	fmt.Printf("  strays            %d container(s) the mesh neither wrote nor holds:\n", len(strays))
+	for _, s := range strays {
+		fmt.Printf("  %-17s %s (%s)\n", "", s.Name, s.Detail)
+	}
+}
+
 // showTunnel is the node show lines about the tunnel an adopted node found and carried (novox/hq
 // ADR 0105): what it presented at enrolment, and what it last said about taking it over.
 func showTunnel(ctx context.Context, inv *inventory.Inventory, name string) error {
@@ -136,7 +156,14 @@ const DefaultFilter = "nftables"
 // take is a module's cutover on an adopted node: the operator's act, done when that module's data
 // has moved. From the next push its resources converge there like any other, replacing what the
 // node found and holds for it.
-func take(ctx context.Context, open *stores, node, module string) (string, error) {
+// takeOptions is what a take was told about the differences it may pass (novox/hq ADR 0163).
+type takeOptions struct {
+	Yes       bool
+	Downgrade bool
+	Replace   map[string]bool
+}
+
+func take(ctx context.Context, open *stores, node, module string, opts takeOptions) (string, error) {
 	inv := open.inventory
 	assigned, err := inv.Assigned(ctx, node)
 	if err != nil {
@@ -150,27 +177,170 @@ func take(ctx context.Context, open *stores, node, module string) (string, error
 			}
 		}
 	}
-	if err := inv.Take(ctx, node, module); err != nil {
+	// The comparison first (novox/hq ADR 0163): every held thing the module would replace, beside
-		return "", err
+	// what the module declares, and the differences that refuse unless named.
-	}
-	said := fmt.Sprintf("%s is taken on %s", module, node)
 	reported, err := inv.AdoptionOf(ctx, node)
 	if err != nil {
 		return "", err
 	}
-	var replaces []string
+	preview, refusals := comparisonOf(reported.Held, module, opts)
-	for _, h := range reported.Held {
+	if len(refusals) > 0 {
-		if h.Module == module {
+		return "", fmt.Errorf("taking %s on %s is refused:\n  %s\n%s", module, node,
-			replaces = append(replaces, "  "+heldLine(h))
+			strings.Join(refusals, "\n  "), preview)
 	}
+	if !opts.Yes {
+		return preview + fmt.Sprintf("\nnothing taken; `take %s %s --yes` cuts it over as previewed", node, module), nil
 	}
-	if len(replaces) > 0 {
+	if err := inv.Take(ctx, node, module); err != nil {
-		said += "; the next push replaces what the node found and holds for it:\n" +
+		return "", err
-			strings.Join(replaces, "\n")
+	}
+	said := fmt.Sprintf("%s is taken on %s", module, node)
+	if preview != "" {
+		said += "; the next push replaces what the node found and holds for it:\n" + preview
 	}
 	return said + fmt.Sprintf("\n  run `push %s` to cut it over", node), nil
 }
 
+// comparisonOf is a take's preview: for every held thing of the module, what runs beside what the
+// module declares, and the refusals the differences earn unless the take named them
+// (novox/hq ADR 0163): an image older than the one running, a declared file that differs from the
+// found one. A narrowed port and a shared network are said and not refused.
+func comparisonOf(held []inventory.Held, module string, opts takeOptions) (string, []string) {
+	var b strings.Builder
+	var refusals []string
+	for _, h := range held {
+		if h.Module != module {
+			continue
+		}
+		fmt.Fprintf(&b, "  %s", heldLine(h))
+		if h.Kept != "" {
+			fmt.Fprintf(&b, ", original kept at %s", h.Kept)
+		}
+		b.WriteString("\n")
+		for _, line := range comparisonLines(h) {
+			fmt.Fprintf(&b, "    %s\n", line)
+		}
+		f := factsOf(h)
+		if f.downgrade && !opts.Downgrade {
+			refusals = append(refusals, fmt.Sprintf("%s: the module's image (%s, made %s) is older than the one running (%s, made %s) — "+
+				"a service that migrated its data forward may not start on it; `--downgrade` to take it anyway",
+				h.Target, f.declaredImage, day(f.declaredCreated), f.image, day(f.imageCreated)))
+		}
+		if f.differs && !opts.Replace[h.Target] && !opts.Replace["*"] {
+			refusals = append(refusals, fmt.Sprintf("%s: the module's content differs from the file found; the lines above "+
+				"marked - are lost by taking it; `--replace %s` to replace it anyway, or declare the file partially",
+				h.Target, h.Target))
+		}
+	}
+	return b.String(), refusals
+}
+
+// facts is a held thing's facts as the preview reads them.
+type facts struct {
+	image, imageCreated, declaredImage, declaredCreated string
+	downgrade, differs                                  bool
+	networks                                            map[string][]string
+	mounts, ports, declaredPorts, declaredVolumes       []string
+	difference                                          []string
+}
+
+func factsOf(h inventory.Held) facts {
+	var f facts
+	if h.Facts == nil {
+		return f
+	}
+	str := func(k string) string { s, _ := h.Facts[k].(string); return s }
+	list := func(k string) []string {
+		var out []string
+		if raw, ok := h.Facts[k].([]any); ok {
+			for _, x := range raw {
+				if s, ok := x.(string); ok {
+					out = append(out, s)
+				}
+			}
+		}
+		return out
+	}
+	f.image, f.imageCreated = str("image"), str("image_created")
+	f.declaredImage, f.declaredCreated = str("declared_image"), str("declared_image_created")
+	f.downgrade, _ = h.Facts["downgrade"].(bool)
+	f.differs, _ = h.Facts["differs"].(bool)
+	f.mounts, f.ports = list("mounts"), list("ports")
+	f.declaredPorts, f.declaredVolumes, f.difference = list("declared_ports"), list("declared_volumes"), list("difference")
+	if raw, ok := h.Facts["networks"].(map[string]any); ok {
+		f.networks = map[string][]string{}
+		for name, members := range raw {
+			var out []string
+			if ms, ok := members.([]any); ok {
+				for _, m := range ms {
+					if s, ok := m.(string); ok {
+						out = append(out, s)
+					}
+				}
+			}
+			f.networks[name] = out
+		}
+	}
+	return f
+}
+
+// comparisonLines says a held thing's facts the way a person weighs them.
+func comparisonLines(h inventory.Held) []string {
+	f := factsOf(h)
+	var out []string
+	if f.image != "" || f.declaredImage != "" {
+		line := fmt.Sprintf("runs %s", orNone(f.image))
+		if f.imageCreated != "" {
+			line += " (made " + day(f.imageCreated) + ")"
+		}
+		line += "; the module declares " + orNone(f.declaredImage)
+		switch {
+		case f.declaredCreated != "":
+			line += " (made " + day(f.declaredCreated) + ")"
+		case f.declaredImage != "":
+			line += " (not on the machine yet, so its age is unknown)"
+		}
+		if f.downgrade {
+			line += " — DOWNGRADE"
+		}
+		out = append(out, line)
+	}
+	names := make([]string, 0, len(f.networks))
+	for n := range f.networks {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	for _, n := range names {
+		if members := f.networks[n]; len(members) > 0 {
+			out = append(out, fmt.Sprintf("on the network %s with %s, which may reach it by name and will not once it moves to the module's own network",
+				n, strings.Join(members, ", ")))
+		}
+	}
+	if len(f.ports) > 0 || len(f.declaredPorts) > 0 {
+		out = append(out, fmt.Sprintf("publishes %s; the module declares %s",
+			orNone(strings.Join(f.ports, " ")), orNone(strings.Join(f.declaredPorts, " "))))
+	}
+	if len(f.mounts) > 0 || len(f.declaredVolumes) > 0 {
+		out = append(out, fmt.Sprintf("mounts %s; the module declares %s",
+			orNone(strings.Join(f.mounts, " ")), orNone(strings.Join(f.declaredVolumes, " "))))
+	}
+	if f.differs {
+		out = append(out, "the declared content differs from the file found (- lost, + new):")
+		for _, d := range f.difference {
+			out = append(out, "  "+d)
+		}
+	}
+	return out
+}
+
+// day is a timestamp as a person reads it in a preview: its date.
+func day(stamp string) string {
+	if len(stamp) >= 10 {
+		return stamp[:10]
+	}
+	return stamp
+}
+
 // reportFreshFor is how old a node's account of itself may be for the flip to act on it. A
 // variable so a test can age a report without waiting.
 var reportFreshFor = 15 * time.Minute
@@ -596,11 +766,30 @@ func adopt(ctx context.Context, open *stores, node string) (string, error) {
 
 // takeCommand, convergeCommand and adoptCommand are the command line's adapters to the acts above.
 func takeCommand(ctx context.Context, args []string) error {
-	if len(args) != 2 {
+	set := flag.NewFlagSet("take", flag.ContinueOnError)
-		return errors.New("take <node> <module>")
+	yes := set.Bool("yes", false, "cut over as previewed; without it the comparison is printed and nothing is taken")
+	downgrade := set.Bool("downgrade", false, "take it although the module's image is older than the one running")
+	var replace stringList
+	set.Var(&replace, "replace", "a found file's path whose content the module may replace although it differs (repeatable; * for every one)")
+	positionals, err := parseAround(set, args)
+	if err != nil {
+		return err
 	}
-	return runAct(ctx, func(open *stores) (string, error) { return take(ctx, open, args[0], args[1]) })
+	if len(positionals) != 2 {
+		return errors.New("take <node> <module> [--yes] [--downgrade] [--replace <path>]...")
 	}
+	opts := takeOptions{Yes: *yes, Downgrade: *downgrade, Replace: map[string]bool{}}
+	for _, r := range replace {
+		opts.Replace[r] = true
+	}
+	return runAct(ctx, func(open *stores) (string, error) { return take(ctx, open, positionals[0], positionals[1], opts) })
+}
+
+// stringList is a repeatable flag.
+type stringList []string
+
+func (l *stringList) String() string     { return strings.Join(*l, ",") }
+func (l *stringList) Set(v string) error { *l = append(*l, v); return nil }
 
 func convergeCommand(ctx context.Context, args []string) error {
 	set := flag.NewFlagSet("converge", flag.ContinueOnError)

cmd/mesh-controller/api.go

@@ -102,7 +102,7 @@ func commands(who Authenticator) http.Handler {
 	}))
 	// Adoption (novox/hq ADR 0100): the same acts as `take`, `converge` and `adopt`.
 	mux.HandleFunc("POST /take", acting(who, true, func(ctx context.Context, open *stores, in request) (string, error) {
-		return take(ctx, open, in.Node, in.Module)
+		return take(ctx, open, in.Node, in.Module, takeOptions{Yes: true})
 	}))
 	mux.HandleFunc("POST /converge", acting(who, false, func(ctx context.Context, open *stores, in request) (string, error) {
 		return converge(ctx, open, in.Node, in.Yes, in.Digest, in.Filter)

cmd/mesh-controller/build.go

@@ -469,10 +469,25 @@ func buildOne(ctx context.Context, source buildSource, path, ref string, wait ti
 	}
 	fmt.Printf("\n%s %s, built on %s from %s\n",
 		manifest.Module, manifest.Version, result.On, short(result.Commit))
+	saysWhenThePolicyActs(ctx, open.inventory, manifest.Module)
 	fmt.Printf("  run `assign <node> %s` to put it somewhere\n", manifest.Module)
 	return nil
 }
 
+// saysWhenThePolicyActs tells whoever built a module that its upgrade policy will send the
+// result on at once (novox/hq issue 126, ADR 0163): a person choreographing a data move must
+// know which module will not wait for them.
+func saysWhenThePolicyActs(ctx context.Context, inv *inventory.Inventory, module string) {
+	if u, err := inv.UpgradeOf(ctx, module); err == nil && u.RollOut {
+		how := "one machine at a time"
+		if u.Together {
+			how = "every machine at once"
+		}
+		fmt.Printf("  %s rolls out on build: the machines running it are sent this now, %s — "+
+			"`upgrade %s record` first if something must move before it does\n", module, how, module)
+	}
+}
+
 // takeIn is what the mesh does with a build's outcome, whoever hears it: the waiting command and
 // the daemon that follows the role's events both come here (novox/hq issue 176), so a build's
 // result reaches the catalogue whether or not the asker was still listening.
@@ -581,6 +596,8 @@ type answers struct {
 	// pair that answers "has it caught up", which waiting alone cannot (the sent digest is
 	// recorded at send, not at apply).
 	reported []inventory.Reported
+	// plans is what the last merges produced and where each stands (novox/hq ADR 0162).
+	plans []inventory.Plan
 	// refused is why a machine cannot be worked out at all, by name. A different thing from every
 	// other answer here: those are about a machine that was told something, and this is about one
 	// that cannot be told anything — it never reaches waiting, because nothing was computed for it

cmd/mesh-controller/dependents_test.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// A merge that rebuilds a base rebuilds what stands on it, through every layer, and nothing else
+// (novox/hq issue 186): the runtime image moving means every module built on it moves too, and a
+// module built on one of those moves as well.
+func TestAMergeOfABaseTakesWhatStandsOnItAlong(t *testing.T) {
+	entry := func(name string) inventory.Entry {
+		return inventory.Entry{Manifest: catalogue.Manifest{Module: name}}
+	}
+	entries := []inventory.Entry{entry("mesh-tools"), entry("shop"), entry("shop-plugin"), entry("postgres"), entry("unrelated")}
+	against := map[string][]string{
+		"shop":        {catalogue.ArtifactStoreScheme + "mesh-tools/runtime@sha256:a"},
+		"shop-plugin": {catalogue.ArtifactStoreScheme + "shop/runtime@sha256:b"},
+		"postgres":    {catalogue.ArtifactStoreScheme + "mesh-tools/runtime@sha256:a"},
+		"unrelated":   {catalogue.ArtifactStoreScheme + "alpine/base@sha256:c"},
+	}
+	got := dependentsOf([]inventory.Entry{entry("mesh-tools")}, entries, against)
+	var names []string
+	for _, e := range got {
+		names = append(names, e.Manifest.Module)
+	}
+	want := map[string]bool{"shop": true, "shop-plugin": true, "postgres": true}
+	if len(names) != len(want) {
+		t.Fatalf("rebuilt %v; wanted exactly the three that stand on the runtime, directly or through shop", names)
+	}
+	for _, n := range names {
+		if !want[n] {
+			t.Fatalf("%s was rebuilt and stands on nothing that moved (%v)", n, names)
+		}
+	}
+	// The dependents come in base order when the merge orders them: the runtime, then shop, then
+	// the plugin that stands on shop.
+	ordered := orderByBases(append([]inventory.Entry{entry("mesh-tools")}, got...), against)
+	pos := map[string]int{}
+	for i, e := range ordered {
+		pos[e.Manifest.Module] = i
+	}
+	if !(pos["mesh-tools"] < pos["shop"] && pos["shop"] < pos["shop-plugin"]) {
+		t.Fatalf("not in base order: %v", ordered)
+	}
+	// Nothing moved: nothing follows.
+	if more := dependentsOf(nil, entries, against); len(more) != 0 {
+		t.Fatalf("with nothing moved, %d module(s) were rebuilt", len(more))
+	}
+}

cmd/mesh-controller/main.go

@@ -72,6 +72,8 @@ func run() error {
 		return askCommand(ctx, args[1:])
 	case "builds":
 		return buildsCommand(ctx, args[1:])
+	case "plans":
+		return plansCommand(ctx, args[1:])
 	case "pin":
 		return pinCommand(ctx, args[1:], true)
 	case "unpin":
@@ -203,7 +205,8 @@ func usage() {
   licence refresh <name>         mint a new access token and seal it to every holder
   rotate <provision> [--consumer <n>]  a new credential for every holder, both ends at once
   ask <module> <tool> [json]           call one of a module's tools over the broker, and print its answer
-  pin <node> <provision> <from>  which node this one gets a provision from
+  pin <node> <provision> <from-node> <module>
+                                 which provider this one gets a provision from: the module, and its node
   unpin <node> <provision>       put that question back
   plan <node> [--files|--json]     what that node would run, and why
   push [<node>] [--behind]       send a node everything it should be, or only those that need it
@@ -252,12 +255,22 @@ func (b builds) Built(ctx context.Context, result link.BuildResult) error {
 	switch {
 	case err != nil && result.Failed != "":
 		fmt.Printf("%s: %v\n", result.ID, err)
+		if result.Module != "" {
+			planBuilt(ctx, b.open, result.Module, result.Commit, result.Failed)
+		} else {
+			planFailedBuild(ctx, b.open, result)
+		}
 		return nil
 	case err != nil:
 		fmt.Printf("%s: heard and recorded, and not registered: %v\n", result.ID, err)
+		if manifest.Module != "" {
+			planBuilt(ctx, b.open, manifest.Module, result.Commit, err.Error())
+		}
 		return nil
 	}
 	fmt.Printf("%s: %s %s registered, built on %s from %s\n",
 		result.ID, manifest.Module, manifest.Version, result.On, short(result.Commit))
+	saysWhenThePolicyActs(ctx, b.inv, manifest.Module)
+	planBuilt(ctx, b.open, manifest.Module, result.Commit, "")
 	return nil
 }

cmd/mesh-controller/modules.go

@@ -411,8 +411,8 @@ func describeOffers(offers []catalogue.Offer) string {
 // database should not change where an existing machine gets its data the day a second one
 // arrives.
 func pinCommand(ctx context.Context, args []string, setting bool) error {
-	if setting && len(args) != 3 {
+	if setting && len(args) != 4 {
-		return errors.New("pin <node> <provision> <from-node>")
+		return errors.New("pin <node> <provision> <from-node> <module>")
 	}
 	if !setting && len(args) != 2 {
 		return errors.New("unpin <node> <provision>")
@@ -431,17 +431,12 @@ func pinCommand(ctx context.Context, args []string, setting bool) error {
 		fmt.Printf("%s is no longer told where to get %s from\n", args[0], args[1])
 		return nil
 	}
-	if args[0] == args[2] {
+	// The provider's node may be this same machine: two modules beside the consumer can both
-		// Allowed by nothing here, and worth saying rather than resolving into a confusing
+	// answer a provision, and then the module is the whole question (novox/hq #258).
-		// refusal later: a node providing something to itself is a node-scoped provision, and
+	if err := inv.PinProvision(ctx, args[0], args[1], args[2], args[3]); err != nil {
-		// this field is for the other kind.
-		return fmt.Errorf("%s cannot get %s from itself; that would be a provision this machine "+
-			"provides, which does not need saying", args[0], args[1])
-	}
-	if err := inv.PinProvision(ctx, args[0], args[1], args[2]); err != nil {
 		return err
 	}
-	fmt.Printf("%s gets %s from %s\n", args[0], args[1], args[2])
+	fmt.Printf("%s gets %s from %s/%s\n", args[0], args[1], args[2], args[3])
 	fmt.Printf("  run `push %s` to send it\n", args[0])
 	return nil
 }
@@ -716,7 +711,9 @@ func claimsFor(ctx context.Context, inv *inventory.Inventory, m catalogue.Manife
 		claimed := seatClaimed{Seat: c.Name, Scope: c.At()}
 		if s, known := byName[c.Name]; known {
 			claimed.Scope = s.Scope
-			claimed.Serves = catalogue.VerbNames(s.Serves)
+			// The verbs the runtime serves for the seat: the claim's own when it names them
+			// (ADR 0160), else every verb the seat promises, which its tools then answer.
+			claimed.Serves = c.ServesFor(catalogue.Manifest{Tools: catalogue.VerbNames(s.Serves)})
 		}
 		out = append(out, claimed)
 	}

cmd/mesh-controller/network.go

@@ -567,6 +567,9 @@ func onTheNetwork(ctx context.Context, inv *inventory.Inventory,
 			catalogue.Node{Name: p.Name, Site: p.Site, Capabilities: caps},
 			catalogue.World{Unchecked: true, Holdings: holdings})
 		if err != nil {
+			// Said, not skipped in silence: a machine dropped here loses its address, and every
+			// plan that names it fails in another module's words (novox/hq issue 188).
+			fmt.Fprintf(os.Stderr, "%s is not counted as on the network: it does not resolve: %v\n", p.Name, err)
 			continue
 		}
 		for _, m := range got.Modules {

cmd/mesh-controller/plan.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"os"
 	"sort"
 	"strings"
 
@@ -281,8 +282,9 @@ func theRestOfTheMesh(ctx context.Context, inv *inventory.Inventory,
 	for _, o := range others {
 		got, err := catalogue.Resolve(shelf, o.assigned, o.node, catalogue.World{Unchecked: true, Holdings: holdings})
 		if err != nil {
-			// Their set does not resolve for some other reason. Not this node's problem to
+			// Said, not skipped: a machine dropped here offers nothing and holds nothing as far
-			// report, and nothing of theirs is running, so it offers nothing.
+			// as every other machine's plan can tell (novox/hq issue 188).
+			fmt.Fprintf(os.Stderr, "%s is left out of the rest of the mesh: it does not resolve: %v\n", o.node.Name, err)
 			continue
 		}
 		firstHeld = append(firstHeld, got.Claims...)
@@ -313,8 +315,22 @@ func theRestOfTheMesh(ctx context.Context, inv *inventory.Inventory,
 	world := catalogue.World{Offered: offered, Held: firstHeld, Holdings: holdings}
 	var held []catalogue.Held
 	for _, o := range others {
-		got, err := catalogue.Resolve(shelf, o.assigned, o.node, world)
+		// Each machine is resolved with its own pins, as its plan is: a machine that needs one to
+		// settle two providers would otherwise be refused here and vanish from the mesh — every
+		// seat it holds unheld, every build that needs one refused (2026-10-01, the control node;
+		// novox/hq issue 188).
+		theirs := world
+		if pins, err := inv.PinsFor(ctx, o.node.Name); err == nil {
+			theirs.Pinned = pins
+		}
+		got, err := catalogue.Resolve(shelf, o.assigned, o.node, theirs)
 		if err != nil {
+			// Said only for the whole-mesh view. With one machine excluded, the others are
+			// resolved without its offers, and one that consumes them cannot resolve here by
+			// design — that is not the machine being dropped, it is the view being partial.
+			if exclude == "" {
+				fmt.Fprintf(os.Stderr, "%s is left out of the rest of the mesh: it does not resolve: %v\n", o.node.Name, err)
+			}
 			continue
 		}
 		held = append(held, got.Claims...)

cmd/mesh-controller/push.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/sha256"
 	"encoding/hex"
+	"encoding/json"
 	"errors"
 	"flag"
 	"fmt"
@@ -112,7 +113,10 @@ func serve(ctx context.Context) error {
 	// while everything else about it looks correct.
 	// And build results nobody was waiting for. A build triggered any other way than `build`
 	// would otherwise be reported into the void, which is the same as not reporting it.
-	server.Records(builds{inv})
+	server.Records(builds{inv, open})
+	// Open plans move on a timer as well as on outcomes (novox/hq ADR 0162): a tier waiting for
+	// machines to report moves when they have, and a plan left by a replaced controller resumes.
+	go planTicker(ctx, open)
 	// And what the catalogue decided a build meant. The builder's own result is already handled
 	// above; this is the other half — the control plane is the only one of the three that knows
 	// which machines run the thing, so it is the one that acts (novox/hq ADR 0072).
@@ -383,6 +387,15 @@ func pushCommand(ctx context.Context, args []string) error {
 	}
 	release()
 	fmt.Printf("\n%d node(s) told\n", len(sending))
+	// And each machine's memberships, as every other send does (ADR 0160): a push is the one most
+	// operators run, and on 2026-10-01 it was the one path that issued none.
+	var told []string
+	for _, s := range sending {
+		told = append(told, s.node)
+	}
+	if err := issueMemberships(ctx, open, server, told); err != nil {
+		return err
+	}
 
 	// **A named push leaves the mesh consistent, not just the machine it named** (novox/hq
 	// issue 057, ADR 0083). Assigning a cross-node consumer mints a provision, and the PROVIDER's
@@ -690,6 +703,51 @@ func sendTo(ctx context.Context, open *stores, names []string) error {
 		}
 		fmt.Printf("  sent %s %d resource(s)\n", s.node, len(s.declared.Resources))
 	}
+	// And every assignment on those machines its membership (novox/hq ADR 0160): composed from the
+	// same records the bus's accounts are, so what a runtime serves and what its account may are one
+	// composition. Issued after the declaration, because the runtime it is for arrives with it.
+	return issueMemberships(ctx, open, server, names)
+}
+
+// issueMemberships publishes the membership of every module on the named machines.
+func issueMemberships(ctx context.Context, open *stores, server *link.Server, names []string) error {
+	records, err := open.inventory.BusRecords(ctx)
+	if err != nil {
+		return err
+	}
+	where := broker.PlacementsOf(records, records.Interchangeable)
+	bus, ok := server.Bus().(link.OverNATS)
+	if !ok {
+		return nil
+	}
+	// The declarations are sent and recorded by now; a membership that cannot be issued is said
+	// and does not unsay them. Every runtime without one serves the shape it derives (ADR 0160), so
+	// the push stands, the first failure is named once, and the next push tries again.
+	issued, failed := 0, 0
+	var first error
+	for _, node := range names {
+		for _, d := range records.Assigned[node] {
+			body, err := json.Marshal(broker.MembershipFor(node, d, where))
+			if err != nil {
+				return err
+			}
+			if err := bus.PublishMembership(ctx, node, d.Module, body); err != nil {
+				if first == nil {
+					first = err
+				}
+				failed++
+				continue
+			}
+			issued++
+		}
+	}
+	if issued > 0 {
+		fmt.Printf("  issued %d membership(s)\n", issued)
+	}
+	if failed > 0 {
+		fmt.Printf("  %d membership(s) could not be issued; the first: %v — the machines keep what "+
+			"they derive until the next push\n", failed, first)
+	}
 	return nil
 }
 

cmd/mesh-controller/readable.go

@@ -39,6 +39,9 @@ type meshStatus struct {
 	// whose is older is still working — and Waiting cannot tell those apart, because the sent
 	// digest is recorded at send, not at apply.
 	Reported []machineReported `json:"reported"`
+	// Plans is what the last merges produced and where each stands (novox/hq ADR 0162): the
+	// open ones first, each saying its tier, what it waits for, and whether it has waited too long.
+	Plans []planStatus `json:"plans"`
 	// Unresolved is every machine that cannot be worked out at all, with what the mesh said when
 	// it tried. **A machine here is in none of the lists above**: nothing was computed for it, so
 	// there is nothing to compare it against and nothing it can be behind — which is why a
@@ -152,7 +155,7 @@ func statusAsJSON(asked answers) ([]byte, error) {
 	out := meshStatus{Machines: len(nodes), Wrong: []machineDoing{},
 		Quiet: []machineQuiet{}, Behind: []moduleBehind{}, Waiting: []machineWaiting{},
 		Reported: []machineReported{}, Unresolved: []machineUnresolved{},
-		Network: asked.network, Adopted: adoptedNodes(nodes)}
+		Network: asked.network, Adopted: adoptedNodes(nodes), Plans: planStatuses(asked.plans, time.Now())}
 	// In a stated order, so two readings of an unchanged mesh are the same document.
 	untakenNodes := make([]string, 0, len(asked.untaken))
 	for name := range asked.untaken {

cmd/mesh-controller/release_plan.go

@@ -0,0 +1,742 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/novox/mesh-controller/internal/inventory"
+	"github.com/novox/mesh-controller/internal/link"
+)
+
+// A merge produces a tiered plan the mesh keeps (novox/hq ADR 0162).
+//
+// The handler that hears the merge computes the plan from the catalogue's one dependency relation,
+// writes it to the store, asks the first tier and returns — the receive loop is never held by a
+// build. Every outcome taken in advances the plan it belongs to; a ticker advances what outcomes
+// alone cannot (a tier waiting for machines to report); a controller replaced mid-plan finds the
+// plan where it left it.
+
+// planWaitBound is how long a plan may wait on one thing before `status` names it red.
+const planWaitBound = 30 * time.Minute
+
+// tiersOf sorts a set of modules into tiers along the ordering edges among them: tier 0 depends
+// on nothing else in the set, tier 1 only on tier 0, and so on. An edge to a module outside the set says
+// nothing about the order inside it. A cycle — which the catalogue should never produce — puts
+// what remains in one last tier rather than losing it, and is said by the caller.
+func tiersOf(set []string, edges []inventory.Edge) [][]string {
+	in := map[string]bool{}
+	for _, m := range set {
+		in[m] = true
+	}
+	deps := map[string]map[string]bool{}
+	for _, m := range set {
+		deps[m] = map[string]bool{}
+	}
+	for _, e := range edges {
+		// A code dependency — B packages A's source — rebuilds B with A, in the same tier: B's
+		// build needs nothing of A's first. The other kinds order: stands-on and declared after
+		// the base is built, built-by after the build machine is built and running — except for
+		// what the build machine itself stands on. The runtime image is built by the builder and
+		// the builder is built on the runtime image; the image comes first, built by the builder
+		// that is running, which is the only one there could be.
+		if !in[e.From] || !in[e.To] || e.From == e.To || e.Kind == inventory.EdgePackages {
+			continue
+		}
+		if e.Kind == inventory.EdgeBuiltBy && isBaseOf(e.From, e.To, edges, in) {
+			continue
+		}
+		deps[e.From][e.To] = true
+	}
+	placed := map[string]bool{}
+	var tiers [][]string
+	for len(placed) < len(set) {
+		var tier []string
+		for _, m := range set {
+			if placed[m] {
+				continue
+			}
+			free := true
+			for d := range deps[m] {
+				if !placed[d] {
+					free = false
+					break
+				}
+			}
+			if free {
+				tier = append(tier, m)
+			}
+		}
+		if len(tier) == 0 {
+			// A cycle: everything left, together, and the caller says so.
+			for _, m := range set {
+				if !placed[m] {
+					tier = append(tier, m)
+				}
+			}
+		}
+		sort.Strings(tier)
+		for _, m := range tier {
+			placed[m] = true
+		}
+		tiers = append(tiers, tier)
+	}
+	return tiers
+}
+
+// isBaseOf says whether `to` stands on `base`, directly or through other bases in the set, along
+// the build edges alone.
+func isBaseOf(base, to string, edges []inventory.Edge, in map[string]bool) bool {
+	seen := map[string]bool{}
+	var walk func(string) bool
+	walk = func(m string) bool {
+		if m == base {
+			return true
+		}
+		if seen[m] {
+			return false
+		}
+		seen[m] = true
+		for _, e := range edges {
+			if e.From == m && in[e.To] && (e.Kind == inventory.EdgeStandsOn || e.Kind == inventory.EdgeDeclared) && walk(e.To) {
+				return true
+			}
+		}
+		return false
+	}
+	return walk(to)
+}
+
+// reachableFrom is the moved modules plus everything that depends on them, through every layer:
+// what a merge rebuilds. Along the code and build edges only: a module *built by* the build machine
+// is not changed by a new build machine, so a built-by edge orders and gates a plan and never
+// widens it — the first plan of 2026-10-01 took the whole catalogue along for a controller change.
+func reachableFrom(moved []string, edges []inventory.Edge) []string {
+	in := map[string]bool{}
+	for _, m := range moved {
+		in[m] = true
+	}
+	for grew := true; grew; {
+		grew = false
+		for _, e := range edges {
+			if e.Kind == inventory.EdgeBuiltBy {
+				continue
+			}
+			if in[e.To] && !in[e.From] {
+				in[e.From] = true
+				grew = true
+			}
+		}
+	}
+	out := make([]string, 0, len(in))
+	for m := range in {
+		out = append(out, m)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// hasCycle says whether the tiers' last tier holds modules that still depend on each other.
+func hasCycle(tiers [][]string, edges []inventory.Edge) bool {
+	if len(tiers) == 0 {
+		return false
+	}
+	last := map[string]bool{}
+	for _, m := range tiers[len(tiers)-1] {
+		last[m] = true
+	}
+	for _, e := range edges {
+		if last[e.From] && last[e.To] {
+			return true
+		}
+	}
+	return false
+}
+
+// planFor is the plan a merge produces: the moved modules and everything reachable from them,
+// tiered, with the merge it answers.
+func planOfMerge(m link.SourceMoved, moved []string, edges []inventory.Edge) inventory.Plan {
+	set := reachableFrom(moved, edges)
+	tiers := tiersOf(set, edges)
+	modules := map[string]*inventory.PlanModule{}
+	for _, name := range set {
+		modules[name] = &inventory.PlanModule{}
+	}
+	return inventory.Plan{
+		ID:         fmt.Sprintf("plan-%d", time.Now().UnixNano()),
+		Repository: m.Owner + "/" + m.Repo,
+		Commit:     m.Commit,
+		Created:    time.Now().UTC(),
+		State:      inventory.PlanBuilding,
+		Tiers:      tiers,
+		Modules:    modules,
+	}
+}
+
+// gates is what the next tier needs running from this one: a module of the tier that a later
+// tier is built by — the runtime dependency — and whose policy rolls it out, must be applied by
+// the machines running it before the next tier is asked. A base an image stands on need only be
+// built; a source another module packages need not even be that.
+func gates(p inventory.Plan, edges []inventory.Edge, rollsOut func(string) bool) []string {
+	if p.Tier >= len(p.Tiers) {
+		return nil
+	}
+	inTier := map[string]bool{}
+	all := map[string]bool{}
+	for _, tier := range p.Tiers {
+		for _, m := range tier {
+			all[m] = true
+		}
+	}
+	for _, m := range p.Tiers[p.Tier] {
+		inTier[m] = true
+	}
+	later := map[string]bool{}
+	for _, tier := range p.Tiers[p.Tier+1:] {
+		for _, m := range tier {
+			later[m] = true
+		}
+	}
+	seen := map[string]bool{}
+	var out []string
+	for _, e := range edges {
+		if later[e.From] && inTier[e.To] && e.Kind == inventory.EdgeBuiltBy && !seen[e.To] && rollsOut(e.To) &&
+			!isBaseOf(e.From, e.To, edges, all) {
+			seen[e.To] = true
+			out = append(out, e.To)
+		}
+	}
+	sort.Strings(out)
+	return out
+}
+
+// applied says whether every machine running the module has reported since the module was built.
+func applied(module string, builtAt time.Time, running []string, reports []inventory.Reported) (bool, []string) {
+	at := map[string]*time.Time{}
+	for _, r := range reports {
+		at[r.Node] = r.At
+	}
+	var waiting []string
+	for _, n := range running {
+		if t := at[n]; t == nil || t.Before(builtAt) {
+			waiting = append(waiting, n)
+		}
+	}
+	return len(waiting) == 0, waiting
+}
+
+// askTier asks the build machine for every module of the tier, and marks each asked. A module
+// the catalogue no longer holds, or whose ask could not be made, is a failure of the plan: a tier
+// half asked is a tier that will never complete.
+func askTier(ctx context.Context, inv *inventory.Inventory, p *inventory.Plan) error {
+	entries, err := inv.Catalogued(ctx)
+	if err != nil {
+		return err
+	}
+	byName := map[string]inventory.Entry{}
+	for _, e := range entries {
+		byName[e.Manifest.Module] = e
+	}
+	now := time.Now().UTC()
+	for _, name := range p.Tiers[p.Tier] {
+		state := p.Modules[name]
+		if state == nil {
+			state = &inventory.PlanModule{}
+			p.Modules[name] = state
+		}
+		e, known := byName[name]
+		if !known {
+			state.State = "failed"
+			state.Why = "no longer in the catalogue"
+			p.State = inventory.PlanFailed
+			p.Note = name + " is no longer in the catalogue"
+			continue
+		}
+		source := buildSource{Repository: e.Source.Repository, Seat: e.Source.Seat}
+		fmt.Printf("  tier %d: ", p.Tier)
+		if err := buildOne(ctx, source, e.Source.Path, e.Source.Ref, 0); err != nil {
+			state.State = "failed"
+			state.Why = err.Error()
+			p.State = inventory.PlanFailed
+			p.Note = fmt.Sprintf("%s could not be asked for: %v", name, err)
+			continue
+		}
+		state.State = "asked"
+		state.AskedAt = &now
+	}
+	return nil
+}
+
+// planBuilt marks a module built (or failed) in every open plan whose current tier holds it, and
+// advances what that completes. Called from the daemon's take-in of every outcome.
+func planBuilt(ctx context.Context, open *stores, module, commit, failed string) {
+	inv := open.inventory
+	plans, err := inv.OpenPlans(ctx)
+	if err != nil {
+		fmt.Printf("plans: cannot read them: %v\n", err)
+		return
+	}
+	now := time.Now().UTC()
+	for i := range plans {
+		p := &plans[i]
+		if p.Tier >= len(p.Tiers) {
+			continue
+		}
+		inTier := false
+		for _, m := range p.Tiers[p.Tier] {
+			if m == module {
+				inTier = true
+			}
+		}
+		if !inTier {
+			continue
+		}
+		state := p.Modules[module]
+		if state == nil {
+			state = &inventory.PlanModule{}
+			p.Modules[module] = state
+		}
+		if failed != "" {
+			state.State = "failed"
+			state.Why = failed
+			p.State = inventory.PlanFailed
+			p.Note = fmt.Sprintf("%s failed to build in tier %d", module, p.Tier)
+		} else {
+			state.State = "built"
+			state.BuiltAt = &now
+			state.Commit = commit
+		}
+		if err := inv.SavePlan(ctx, *p); err != nil {
+			fmt.Printf("%s: cannot keep the plan: %v\n", p.ID, err)
+			continue
+		}
+		if p.State == inventory.PlanFailed {
+			fmt.Printf("%s: %s; the tiers after it are not asked\n", p.ID, p.Note)
+		}
+	}
+	advancePlans(ctx, open)
+}
+
+// advancePlans moves every open plan as far as the facts allow: a tier whose modules are all built
+// and whose gates are applied gives way to the next; the last tier done is the plan done. Called
+// after every outcome and on a timer, so a plan waiting on a machine's report moves when it comes.
+func advancePlans(ctx context.Context, open *stores) {
+	inv := open.inventory
+	plans, err := inv.OpenPlans(ctx)
+	if err != nil {
+		fmt.Printf("plans: cannot read them: %v\n", err)
+		return
+	}
+	if len(plans) == 0 {
+		return
+	}
+	edges, err := inv.Dependencies(ctx)
+	if err != nil {
+		fmt.Printf("plans: cannot read the dependencies: %v\n", err)
+		return
+	}
+	rollsOut := func(module string) bool {
+		u, err := inv.UpgradeOf(ctx, module)
+		return err == nil && u.RollOut
+	}
+	for i := range plans {
+		p := &plans[i]
+		for p.Open() {
+			moved, err := advanceOnce(ctx, open, p, edges, rollsOut)
+			if err != nil {
+				fmt.Printf("%s: %v\n", p.ID, err)
+				break
+			}
+			if err := inv.SavePlan(ctx, *p); err != nil {
+				fmt.Printf("%s: cannot keep the plan: %v\n", p.ID, err)
+				break
+			}
+			if !moved {
+				break
+			}
+		}
+	}
+}
+
+// advanceOnce takes one step of one plan and says whether anything changed.
+func advanceOnce(ctx context.Context, open *stores, p *inventory.Plan,
+	edges []inventory.Edge, rollsOut func(string) bool) (bool, error) {
+	inv := open.inventory
+	if p.Tier >= len(p.Tiers) {
+		p.State = inventory.PlanDone
+		fmt.Printf("%s: done — %s at %s, %d tier(s)\n", p.ID, p.Repository, short(p.Commit), len(p.Tiers))
+		return true, nil
+	}
+	tier := p.Tiers[p.Tier]
+	// Not yet asked: ask.
+	unasked := 0
+	for _, m := range tier {
+		if s := p.Modules[m]; s == nil || s.State == "" {
+			unasked++
+		}
+	}
+	if unasked == len(tier) {
+		if err := askTier(ctx, inv, p); err != nil {
+			return false, err
+		}
+		return true, nil
+	}
+	// Asked: wait for every build.
+	var latest time.Time
+	for _, m := range tier {
+		s := p.Modules[m]
+		if s == nil || s.State != "built" {
+			return false, nil
+		}
+		if s.BuiltAt != nil && s.BuiltAt.After(latest) {
+			latest = *s.BuiltAt
+		}
+	}
+	// Built: send every module of the tier whose policy rolls out, once, to the machines running
+	// it — whether or not its source commit moved. A dependent rebuilt because its base moved, or
+	// a module that packages another repository's source, keeps its commit; the catalogue announces
+	// no move for it and its machines would keep the old image until somebody pushed (novox/hq
+	// issue 189). A module whose policy records is built and left, as its policy says.
+	for _, m := range tier {
+		state := p.Modules[m]
+		if state == nil || state.SentAt != nil || !rollsOut(m) {
+			continue
+		}
+		running, err := inv.Running(ctx, m)
+		if err != nil {
+			return false, err
+		}
+		now := time.Now().UTC()
+		state.SentAt = &now
+		if len(running) == 0 {
+			continue
+		}
+		if err := sendTo(ctx, open, running); err != nil {
+			return false, fmt.Errorf("sending %s to %s after tier %d: %w", m, strings.Join(running, ", "), p.Tier, err)
+		}
+		fmt.Printf("%s: tier %d built; sent %s to %s\n", p.ID, p.Tier, m, strings.Join(running, ", "))
+		return true, nil
+	}
+	// And wait for what the next tier needs running.
+	needed := gates(*p, edges, rollsOut)
+	if len(needed) > 0 {
+		reports, err := inv.LastReports(ctx)
+		if err != nil {
+			return false, err
+		}
+		var waiting []string
+		for _, m := range needed {
+			running, err := inv.Running(ctx, m)
+			if err != nil {
+				return false, err
+			}
+			state := p.Modules[m]
+			if state == nil {
+				state = &inventory.PlanModule{}
+				p.Modules[m] = state
+			}
+			// The plan sends what it waits for. A rebuild from the same source commit is not a
+			// move the catalogue announces — the build machine rebuilt for a controller change
+			// is one — so the roll-out that opens this gate is the plan's to make, once, and
+			// the reports that open it are the ones after the send.
+			since := latest
+			if state.BuiltAt != nil {
+				since = *state.BuiltAt
+			}
+			if state.SentAt != nil && state.SentAt.After(since) {
+				since = *state.SentAt
+			}
+			if ok, on := applied(m, since, running, reports); !ok {
+				waiting = append(waiting, fmt.Sprintf("%s on %s", m, strings.Join(on, ", ")))
+			}
+		}
+		if len(waiting) > 0 {
+			note := "tier " + fmt.Sprint(p.Tier) + " built; waiting for " + strings.Join(waiting, "; ") + " to be applied"
+			changed := p.State != inventory.PlanRolling || p.Note != note
+			p.State = inventory.PlanRolling
+			p.Note = note
+			return changed, nil
+		}
+	}
+	p.Tier++
+	p.State = inventory.PlanBuilding
+	p.Note = ""
+	if p.Tier < len(p.Tiers) {
+		fmt.Printf("%s: tier %d done; asking tier %d: %s\n", p.ID, p.Tier-1, p.Tier, strings.Join(p.Tiers[p.Tier], ", "))
+	}
+	return true, nil
+}
+
+// planTicker advances open plans on a timer, for the steps outcomes alone cannot take.
+func planTicker(ctx context.Context, open *stores) {
+	advancePlans(ctx, open)
+	tick := time.NewTicker(30 * time.Second)
+	defer tick.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-tick.C:
+			advancePlans(ctx, open)
+		}
+	}
+}
+
+// planLine is one plan as `status` says it.
+func planLine(p inventory.Plan, now time.Time) string {
+	where := fmt.Sprintf("tier %d of %d", min(p.Tier+1, len(p.Tiers)), len(p.Tiers))
+	switch p.State {
+	case inventory.PlanDone:
+		return fmt.Sprintf("%s %s done, %d tier(s)", p.Repository, short(p.Commit), len(p.Tiers))
+	case inventory.PlanFailed:
+		return fmt.Sprintf("%s %s FAILED at %s: %s", p.Repository, short(p.Commit), where, p.Note)
+	}
+	since := now.Sub(p.Updated).Round(time.Minute)
+	late := ""
+	if since > planWaitBound {
+		late = " — LATE"
+	}
+	what := "building"
+	if p.State == inventory.PlanRolling {
+		what = p.Note
+	}
+	return fmt.Sprintf("%s %s %s, %s for %s%s", p.Repository, short(p.Commit), where, what, since, late)
+}
+
+// planFailedBuild marks the module a failed build was for when the result names no module: by the
+// repository and path the plan's modules were asked at.
+func planFailedBuild(ctx context.Context, open *stores, result link.BuildResult) {
+	entries, err := open.inventory.Catalogued(ctx)
+	if err != nil {
+		return
+	}
+	for _, e := range entries {
+		if repositoryMatches(e.Source.Repository, result.Repository) && e.Source.Path == result.Path {
+			planBuilt(ctx, open, e.Manifest.Module, result.Commit, result.Failed)
+			return
+		}
+	}
+}
+
+func repositoryMatches(a, b string) bool {
+	trim := func(s string) string { return strings.ToLower(strings.TrimSuffix(s, ".git")) }
+	return trim(a) == trim(b) || strings.HasSuffix(trim(a), "/"+trim(b)) || strings.HasSuffix(trim(b), "/"+trim(a))
+}
+
+// planStatus is one plan as `status --json` says it.
+type planStatus struct {
+	ID         string    `json:"id"`
+	Repository string    `json:"repository"`
+	Commit     string    `json:"commit"`
+	State      string    `json:"state"`
+	Tier       int       `json:"tier"`
+	Tiers      int       `json:"tiers"`
+	Waiting    string    `json:"waiting,omitempty"`
+	Since      time.Time `json:"since"`
+	Late       bool      `json:"late"`
+}
+
+func planStatuses(plans []inventory.Plan, now time.Time) []planStatus {
+	out := make([]planStatus, 0, len(plans))
+	for _, p := range plans {
+		ps := planStatus{ID: p.ID, Repository: p.Repository, Commit: p.Commit, State: p.State,
+			Tier: p.Tier, Tiers: len(p.Tiers), Since: p.Updated}
+		if p.Open() {
+			ps.Waiting = p.Note
+			if ps.Waiting == "" {
+				ps.Waiting = "builds of tier " + fmt.Sprint(p.Tier)
+			}
+			ps.Late = now.Sub(p.Updated) > planWaitBound
+		}
+		out = append(out, ps)
+	}
+	return out
+}
+
+// openPlans is the open plans among the recent ones, and how many have waited past the bound.
+func openPlans(plans []inventory.Plan) ([]inventory.Plan, int) {
+	var open []inventory.Plan
+	late := 0
+	for _, p := range plans {
+		if p.Open() {
+			open = append(open, p)
+			if time.Since(p.Updated) > planWaitBound {
+				late++
+			}
+		}
+	}
+	return open, late
+}
+
+// plansCommand says what the last merges produced and where each stands; given an id, one plan
+// tier by tier with every module's state.
+func plansCommand(ctx context.Context, args []string) error {
+	set := flag.NewFlagSet("plans", flag.ContinueOnError)
+	limit := set.Int("n", 10, "how many to show")
+	whatIf := set.String("what-if", "", "owner/repository: the plan a merge there would produce, saving nothing — with --paths or --modules")
+	paths := set.String("paths", "", "the files the merge would change, comma-separated, from the repository's root")
+	modules := set.String("modules", "", "or the modules it would change, comma-separated")
+	positionals, err := parseAround(set, args)
+	if err != nil {
+		return err
+	}
+	open, err := openStores(ctx)
+	if err != nil {
+		return err
+	}
+	defer open.Close()
+	inv := open.inventory
+	now := time.Now()
+	if len(positionals) == 1 {
+		p, err := inv.PlanByID(ctx, positionals[0])
+		if err != nil {
+			return err
+		}
+		fmt.Printf("%s — %s\n", p.ID, planLine(p, now))
+		for i, tier := range p.Tiers {
+			marker := " "
+			if i == p.Tier && p.Open() {
+				marker = ">"
+			}
+			fmt.Printf("%s tier %d\n", marker, i)
+			for _, m := range tier {
+				s := p.Modules[m]
+				state := "not yet asked"
+				if s != nil && s.State != "" {
+					state = s.State
+					if s.Commit != "" {
+						state += " from " + short(s.Commit)
+					}
+					if s.Why != "" {
+						state += ": " + s.Why
+					}
+				}
+				fmt.Printf("    %-22s %s\n", m, state)
+			}
+		}
+		return nil
+	}
+	if *whatIf != "" {
+		return planWhatIf(ctx, inv, *whatIf, splitList(*paths), splitList(*modules))
+	}
+	if len(positionals) == 2 && positionals[0] == "stop" {
+		p, err := inv.PlanByID(ctx, positionals[1])
+		if err != nil {
+			return err
+		}
+		if !p.Open() {
+			return fmt.Errorf("%s is already %s", p.ID, p.State)
+		}
+		p.State = inventory.PlanFailed
+		p.Note = "stopped by hand at tier " + fmt.Sprint(p.Tier)
+		if err := inv.SavePlan(ctx, p); err != nil {
+			return err
+		}
+		fmt.Printf("%s stopped at tier %d of %d; what was asked still builds and registers, nothing further is asked\n",
+			p.ID, p.Tier, len(p.Tiers))
+		return nil
+	}
+	plans, err := inv.RecentPlans(ctx, *limit)
+	if err != nil {
+		return err
+	}
+	if len(plans) == 0 {
+		fmt.Println("no merge has produced a plan yet")
+		return nil
+	}
+	for _, p := range plans {
+		fmt.Printf("%-28s %s\n", p.ID, planLine(p, now))
+	}
+	return nil
+}
+
+// planWhatIf is the plan a merge would produce, computed the way the merge handler computes one
+// and saved nowhere: the modules the repository's changed files touch (or the modules named), what
+// packages their source, everything reachable from them, in tiers. For reading before merging.
+func planWhatIf(ctx context.Context, inv *inventory.Inventory, repository string, paths, modules []string) error {
+	owner, repo, found := strings.Cut(repository, "/")
+	if !found {
+		return fmt.Errorf("--what-if takes owner/repository, not %q", repository)
+	}
+	m := link.SourceMoved{Owner: owner, Repo: repo, Base: "main", Commit: "what-if", Paths: paths}
+	entries, err := inv.Catalogued(ctx)
+	if err != nil {
+		return err
+	}
+	read, err := inv.ReadRepositories(ctx)
+	if err != nil {
+		return err
+	}
+	var from, packaging []inventory.Entry
+	named := map[string]bool{}
+	for _, name := range modules {
+		named[name] = true
+	}
+	for _, e := range entries {
+		switch {
+		case named[e.Manifest.Module]:
+			from = append(from, e)
+		case len(named) == 0 && sourceIs(e.Source, m):
+			from = append(from, e)
+		case readsFrom(read[e.Manifest.Module], m):
+			packaging = append(packaging, e)
+		}
+	}
+	if len(named) == 0 {
+		from = whatTheMergeTouched(from, entries, m)
+	}
+	moved := append(append([]inventory.Entry{}, from...), packaging...)
+	if len(moved) == 0 {
+		fmt.Printf("a merge of %s changing %s would build nothing the mesh holds\n", repository,
+			orNone(strings.Join(append(paths, modules...), ", ")))
+		return nil
+	}
+	edges, err := inv.Dependencies(ctx)
+	if err != nil {
+		return err
+	}
+	var names []string
+	for _, e := range moved {
+		names = append(names, e.Manifest.Module)
+	}
+	p := planOfMerge(m, names, edges)
+	fmt.Printf("a merge of %s would build %d module(s) in %d tier(s):\n", repository, len(p.Modules), len(p.Tiers))
+	rolls := map[string]string{}
+	for i, tier := range p.Tiers {
+		fmt.Printf("  tier %d\n", i)
+		for _, name := range tier {
+			how := "built; its policy records, so nothing is sent"
+			if u, err := inv.UpgradeOf(ctx, name); err == nil && u.RollOut {
+				running, _ := inv.Running(ctx, name)
+				how = "built, then sent to " + orNone(strings.Join(running, ", "))
+				rolls[name] = how
+			}
+			fmt.Printf("    %-22s %s\n", name, how)
+		}
+	}
+	if hasCycle(p.Tiers, edges) {
+		fmt.Println("  the last tier depends on itself and would be built together, in no order")
+	}
+	if len(packaging) > 0 {
+		var also []string
+		for _, e := range packaging {
+			also = append(also, e.Manifest.Module)
+		}
+		fmt.Printf("  %s package source from %s, so they are rebuilt without their own source moving\n",
+			strings.Join(also, ", "), repository)
+	}
+	return nil
+}
+
+func splitList(s string) []string {
+	var out []string
+	for _, part := range strings.Split(s, ",") {
+		if part = strings.TrimSpace(part); part != "" {
+			out = append(out, part)
+		}
+	}
+	return out
+}

cmd/mesh-controller/release_plan_test.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-controller/internal/inventory"
+	"github.com/novox/mesh-controller/internal/link"
+)
+
+// A merge produces a tiered plan (novox/hq ADR 0162): what moved and everything reachable from it,
+// sorted so a tier depends only on earlier ones — with the three kinds of dependency told apart.
+func TestAMergeIsPlannedInTiersAlongTheThreeKindsOfDependency(t *testing.T) {
+	edges := []inventory.Edge{
+		// build dependencies: images on the runtime, a plugin on one of them
+		{From: "shop", To: "mesh-tools", Kind: inventory.EdgeStandsOn},
+		{From: "postgres", To: "mesh-tools", Kind: inventory.EdgeStandsOn},
+		{From: "shop-plugin", To: "shop", Kind: inventory.EdgeDeclared},
+		// a code dependency: the proxy packages the controller's source — same tier
+		{From: "route-proxy", To: "mesh-controller", Kind: inventory.EdgePackages},
+		{From: "builder", To: "mesh-controller", Kind: inventory.EdgePackages},
+		// runtime dependencies: everything source-built is built by the builder
+		{From: "shop", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "postgres", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "shop-plugin", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "route-proxy", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "mesh-controller", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "mesh-tools", To: "builder", Kind: inventory.EdgeBuiltBy},
+		{From: "builder", To: "mesh-tools", Kind: inventory.EdgeStandsOn},
+		{From: "unrelated", To: "alpine", Kind: inventory.EdgeStandsOn},
+	}
+	// The runtime image moved: everything on it, and what is built by what is on it.
+	set := reachableFrom([]string{"mesh-tools"}, edges)
+	// What stands on the runtime, and the builder that stands on it; not the controller, which the
+	// builder merely builds, nor the proxy that packages the controller.
+	want := []string{"builder", "mesh-tools", "postgres", "shop", "shop-plugin"}
+	if len(set) != len(want) {
+		t.Fatalf("reachable from the runtime: %v, want %v", set, want)
+	}
+	tiers := tiersOf(set, edges)
+	pos := map[string]int{}
+	for i, tier := range tiers {
+		for _, m := range tier {
+			pos[m] = i
+		}
+	}
+	if pos["mesh-tools"] != 0 || pos["builder"] != 1 {
+		t.Fatalf("the runtime then the builder: %v", tiers)
+	}
+	if !(pos["shop"] > pos["builder"] && pos["postgres"] > pos["builder"]) {
+		t.Fatalf("what the builder builds comes after the builder: %v", tiers)
+	}
+	if pos["shop-plugin"] <= pos["shop"] {
+		t.Fatalf("a plugin after what it is declared on: %v", tiers)
+	}
+	if hasCycle(tiers, edges) {
+		t.Fatalf("no cycle here: %v", tiers)
+	}
+
+	// The controller alone moved: the proxy with it, nothing else.
+	small := reachableFrom([]string{"mesh-controller"}, edges)
+	if len(small) != 3 {
+		t.Fatalf("a controller merge rebuilds the controller and what packages it: %v", small)
+	}
+	// The builder packages the controller's source (same tier by that edge) and the controller is
+	// built by the builder (next tier by that one): the builder first, then the controller and the
+	// proxy together — a code dependency in one tier, a runtime dependency across tiers.
+	smallTiers := tiersOf(small, edges)
+	if len(smallTiers) != 2 || smallTiers[0][0] != "builder" || len(smallTiers[1]) != 2 {
+		t.Fatalf("the builder, then the controller and the proxy together: %v", smallTiers)
+	}
+	// The builder alone moved: the builder, and nothing it builds.
+	if only := reachableFrom([]string{"builder"}, edges); len(only) != 1 {
+		t.Fatalf("a build machine change rebuilds the build machine alone: %v", only)
+	}
+
+	// Only a runtime dependency gates on deployment, and only when the module rolls out.
+	p := planOfMerge(link.SourceMoved{Owner: "novox", Repo: "mesh-tools", Commit: "abc"}, []string{"mesh-tools"}, edges)
+	p.Tier = pos["builder"]
+	rollsOut := func(m string) bool { return m == "builder" }
+	if g := gates(p, edges, rollsOut); len(g) != 1 || g[0] != "builder" {
+		t.Fatalf("the builder gates the tier after it: %v", g)
+	}
+	p.Tier = 0
+	if g := gates(p, edges, rollsOut); len(g) != 0 {
+		t.Fatalf("the runtime image is a build dependency and gates nothing: %v", g)
+	}
+	if g := gates(p, edges, func(string) bool { return false }); len(g) != 0 {
+		t.Fatalf("a module that only records its upgrade gates nothing: %v", g)
+	}
+}
+
+// A gate is open once every machine running the module has reported after it was built.
+func TestAGateOpensWhenTheMachinesHaveReportedSinceTheBuild(t *testing.T) {
+	built := time.Date(2026, 10, 1, 15, 0, 0, 0, time.UTC)
+	before, after := built.Add(-time.Minute), built.Add(time.Minute)
+	reports := []inventory.Reported{{Node: "anchor", At: &after}, {Node: "home-server", At: &before}}
+	ok, waiting := applied("builder", built, []string{"anchor", "home-server"}, reports)
+	if ok || len(waiting) != 1 || waiting[0] != "home-server" {
+		t.Fatalf("one machine has not reported since the build: ok=%v waiting=%v", ok, waiting)
+	}
+	if ok, _ := applied("builder", built, []string{"anchor"}, reports); !ok {
+		t.Fatal("the machine that reported after the build holds the gate open")
+	}
+	if ok, _ := applied("builder", built, nil, reports); !ok {
+		t.Fatal("a module running nowhere gates nothing")
+	}
+}
+
+// A cycle is not lost: what remains is one last tier, and the caller says so.
+func TestACycleIsOneLastTierAndSaidSo(t *testing.T) {
+	edges := []inventory.Edge{{From: "a", To: "b", Kind: inventory.EdgeStandsOn}, {From: "b", To: "a", Kind: inventory.EdgeStandsOn}}
+	tiers := tiersOf([]string{"a", "b"}, edges)
+	if len(tiers) != 1 || len(tiers[0]) != 2 || !hasCycle(tiers, edges) {
+		t.Fatalf("a cycle should be one tier of two, said: %v", tiers)
+	}
+}

cmd/mesh-controller/seatverbs.go

@@ -69,6 +69,24 @@ func argvFor(verb string, args map[string]any) ([]string, error) {
 			return []string{"builds", m}, nil
 		}
 		return []string{"builds"}, nil
+	case "plans":
+		if r := str("repository"); r != "" {
+			argv := []string{"plans", "--what-if", r}
+			if p := str("paths"); p != "" {
+				argv = append(argv, "--paths", p)
+			}
+			if m := str("modules"); m != "" {
+				argv = append(argv, "--modules", m)
+			}
+			return argv, nil
+		}
+		if id := str("stop"); id != "" {
+			return []string{"plans", "stop", id}, nil
+		}
+		if id := str("id"); id != "" {
+			return []string{"plans", id}, nil
+		}
+		return []string{"plans"}, nil
 	case "plan":
 		if err := need("node"); err != nil {
 			return nil, err
@@ -79,6 +97,16 @@ func argvFor(verb string, args map[string]any) ([]string, error) {
 			return nil, err
 		}
 		return []string{verb, str("node"), str("module")}, nil
+	case "pin":
+		if err := need("node", "provision", "from", "module"); err != nil {
+			return nil, err
+		}
+		return []string{"pin", str("node"), str("provision"), str("from"), str("module")}, nil
+	case "unpin":
+		if err := need("node", "provision"); err != nil {
+			return nil, err
+		}
+		return []string{"unpin", str("node"), str("provision")}, nil
 	case "push":
 		// Sent and not waited for: the asker reads `status` for what the machine did, which is
 		// what a person at a shell does too. A tool call that blocked for a push's whole apply would
@@ -176,7 +204,7 @@ func seatToolHandlers() (map[string]link.ToolHandler, error) {
 			}
 			continue
 		}
-		if _, err := argvFor(verb, map[string]any{"node": "x", "module": "x", "repository": "x"}); err != nil {
+		if _, err := argvFor(verb, sampleArguments(v)); err != nil {
 			return nil, fmt.Errorf("the %s seat's row declares %q, which this control plane cannot run: %w",
 				catalogue.ControllerSeatName, verb, err)
 		}
@@ -215,3 +243,22 @@ func seatTools() map[string]any {
 	}
 	return map[string]any{"seats": seats}
 }
+
+// sampleArguments is one of every argument a verb's schema requires, so the check at start proves the
+// verb runnable rather than that it happens to want the arguments the check guessed.
+func sampleArguments(v catalogue.Verb) map[string]any {
+	sample := map[string]any{"node": "x", "module": "x", "repository": "x"}
+	switch required := v.Input["required"].(type) {
+	case []string:
+		for _, k := range required {
+			sample[k] = "x"
+		}
+	case []any:
+		for _, k := range required {
+			if name, ok := k.(string); ok {
+				sample[name] = "x"
+			}
+		}
+	}
+	return sample
+}

cmd/mesh-controller/status.go

@@ -138,6 +138,18 @@ func printStatus(asked answers) error {
 			len(quiet), strings.Join(said, "\n  "))
 	}
 
+	if open, late := openPlans(asked.plans); len(open) > 0 {
+		fmt.Printf("%d plan(s) open", len(open))
+		if late > 0 {
+			fmt.Printf(", %d waiting past %s", late, planWaitBound)
+		}
+		fmt.Println(":")
+		for _, p := range open {
+			fmt.Printf("  %s\n", planLine(p, time.Now()))
+		}
+		fmt.Println()
+	}
+
 	if len(behind) > 0 {
 		var names []string
 		for m := range behind {
@@ -289,7 +301,10 @@ func firstLine(s string) string {
 // A type of its own rather than a method on the enrolment, because they are unrelated things
 // arriving on one queue and an implementation of one should not have to say anything about the
 // other.
-type builds struct{ inv *inventory.Inventory }
+type builds struct {
+	inv  *inventory.Inventory
+	open *stores
+}
 
 // theThreeQuestions reads what anything answering "is the mesh alright" needs.
 //
@@ -342,6 +357,10 @@ func theThreeQuestions(ctx context.Context, open *stores) (answers, error) {
 	if err != nil {
 		return answers{}, err
 	}
+	out.plans, err = inv.RecentPlans(ctx, 5)
+	if err != nil {
+		return answers{}, err
+	}
 
 	// And which machines are not running what the mesh would send them. The same question as a
 	// module being behind its source, one level down: that one says the catalogue is out of date,

cmd/mesh-controller/take_preview_test.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// A take is a comparison (novox/hq ADR 0163): the preview puts what runs beside what the module
+// declares, and an older image or a differing file refuses unless named.
+func TestATakePreviewsTheComparisonAndRefusesWhatIsNotNamed(t *testing.T) {
+	held := []inventory.Held{
+		{ID: "forge.server", Module: "forge", Kind: "container", Target: "forge", Facts: map[string]any{
+			"image": "forge:1.27.3", "image_created": "2026-09-17T10:00:00Z",
+			"declared_image": "forge:1.22.6", "declared_image_created": "2026-08-20T10:00:00Z", "downgrade": true,
+			"networks": map[string]any{"predecessor_default": []any{"office", "db"}},
+			"ports":    []any{"3000/tcp>0.0.0.0:3000"}, "declared_ports": []any{"3000:3000"},
+		}},
+		{ID: "forge.config", Module: "forge", Kind: "file", Target: "/etc/forge/app.ini", Kept: "/var/lib/mesh/kept/app.ini",
+			Facts: map[string]any{"differs": true, "difference": []any{"- private scope: local", "+ upstream: public"}}},
+		{ID: "other.server", Module: "other", Kind: "container", Target: "other"},
+	}
+	preview, refusals := comparisonOf(held, "forge", takeOptions{})
+	for _, want := range []string{"runs forge:1.27.3 (made 2026-09-17)", "declares forge:1.22.6 (made 2026-08-20)", "DOWNGRADE",
+		"on the network predecessor_default with office, db", "publishes 3000/tcp>0.0.0.0:3000; the module declares 3000:3000",
+		"- private scope: local", "original kept at /var/lib/mesh/kept/app.ini"} {
+		if !strings.Contains(preview, want) {
+			t.Errorf("the preview lacks %q:\n%s", want, preview)
+		}
+	}
+	if strings.Contains(preview, "other") {
+		t.Errorf("another module's held things are in the preview:\n%s", preview)
+	}
+	if len(refusals) != 2 || !strings.Contains(refusals[0], "--downgrade") || !strings.Contains(refusals[1], "--replace /etc/forge/app.ini") {
+		t.Fatalf("the downgrade and the differing file refuse, each naming its override: %v", refusals)
+	}
+	// Named, they pass.
+	if _, refusals := comparisonOf(held, "forge", takeOptions{Downgrade: true, Replace: map[string]bool{"/etc/forge/app.ini": true}}); len(refusals) != 0 {
+		t.Fatalf("named differences still refused: %v", refusals)
+	}
+	if _, refusals := comparisonOf(held, "forge", takeOptions{Downgrade: true, Replace: map[string]bool{"*": true}}); len(refusals) != 0 {
+		t.Fatalf("replace * did not cover the file: %v", refusals)
+	}
+	// A held thing with no facts yet — a host older than this — refuses nothing and says what it can.
+	if preview, refusals := comparisonOf(held, "other", takeOptions{}); len(refusals) != 0 || !strings.Contains(preview, "container other") {
+		t.Fatalf("a factless hold: %q %v", preview, refusals)
+	}
+}

cmd/mesh-controller/upgrades.go

@@ -295,17 +295,31 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 			"built from\n", m.Owner, m.Repo, m.Base, m.Commit)
 		return nil
 	}
-	against, err := inv.BuiltAgainst(ctx)
+	// A merge produces a plan the mesh keeps (novox/hq ADR 0162): what moved and everything that
+	// depends on it, along the catalogue's one dependency relation, sorted into tiers. The plan is
+	// written before any build is asked; the first tier is asked; this returns. Outcomes advance it.
+	edges, err := inv.Dependencies(ctx)
 	if err != nil {
 		return notNow(err)
 	}
-	ordered := orderByBases(moved, against)
+	var movedNames []string
-	names := make([]string, 0, len(ordered))
+	for _, e := range moved {
-	for _, e := range ordered {
+		movedNames = append(movedNames, e.Manifest.Module)
-		names = append(names, e.Manifest.Module)
 	}
-	fmt.Printf("%s/%s merged into %s (%.8s); building %s\n",
+	plan := planOfMerge(m, movedNames, edges)
-		m.Owner, m.Repo, m.Base, m.Commit, strings.Join(names, ", "))
+	if hasCycle(plan.Tiers, edges) {
+		fmt.Printf("  the last tier depends on itself: %s — built together, in no order\n",
+			strings.Join(plan.Tiers[len(plan.Tiers)-1], ", "))
+	}
+	if err := inv.SavePlan(ctx, plan); err != nil {
+		return notNow(err)
+	}
+	var tiers []string
+	for i, t := range plan.Tiers {
+		tiers = append(tiers, fmt.Sprintf("%d: %s", i, strings.Join(t, ", ")))
+	}
+	fmt.Printf("%s/%s merged into %s (%.8s); plan %s, %d module(s) in %d tier(s)\n  %s\n",
+		m.Owner, m.Repo, m.Base, m.Commit, plan.ID, len(plan.Modules), len(plan.Tiers), strings.Join(tiers, "\n  "))
 	if len(packaging) > 0 {
 		var also []string
 		for _, e := range packaging {
@@ -314,22 +328,11 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 		fmt.Printf("  %s package source from it, so they are rebuilt and their own source record "+
 			"is left where it is\n", strings.Join(also, ", "))
 	}
-	var failed []string
+	if err := askTier(ctx, inv, &plan); err != nil {
-	for _, e := range ordered {
+		return notNow(err)
-		source := buildSource{Repository: e.Source.Repository, Seat: e.Source.Seat}
-		if err := buildOne(ctx, source, e.Source.Path, e.Source.Ref, 20*time.Minute); err != nil {
-			fmt.Printf("  %s: %v\n", e.Manifest.Module, err)
-			failed = append(failed, e.Manifest.Module)
-			// A base that failed is a reason to stop: what stands on it would be built against
-			// the old one, and report success (novox/hq 04-ISSUES/131).
-			if standsOn(ordered, e.Manifest.Module, against) {
-				fmt.Printf("  stopping: %s is a base of what was still to build\n", e.Manifest.Module)
-				break
 	}
-		}
+	if err := inv.SavePlan(ctx, plan); err != nil {
-	}
+		return notNow(err)
-	if len(failed) > 0 {
-		fmt.Printf("%d of %d not built: %s\n", len(failed), len(ordered), strings.Join(failed, ", "))
 	}
 	return nil
 }
@@ -522,3 +525,37 @@ func isHistory(mergedAt string, seen time.Time) bool {
 	}
 	return at.Before(seen)
 }
+
+// dependentsOf is every catalogued module that stands on one of the moved modules, directly or
+// through another dependent, and is not itself among them — in the catalogue's order, so the
+// answer is the same each time. A module standing on nothing that moved is left alone: a merge
+// rebuilds what it changed and what is built on top of that, not the catalogue.
+func dependentsOf(moved, entries []inventory.Entry, against map[string][]string) []inventory.Entry {
+	bases := map[string]bool{}
+	for _, e := range moved {
+		bases[e.Manifest.Module] = true
+	}
+	var out []inventory.Entry
+	taken := map[string]bool{}
+	for grew := true; grew; {
+		grew = false
+		for _, e := range entries {
+			name := e.Manifest.Module
+			if bases[name] || taken[name] {
+				continue
+			}
+			for base := range bases {
+				if standsOnModule(e, base, against) {
+					taken[name] = true
+					out = append(out, e)
+					grew = true
+					break
+				}
+			}
+		}
+		for _, e := range out {
+			bases[e.Manifest.Module] = true
+		}
+	}
+	return out
+}

internal/broker/derived.go

@@ -161,8 +161,15 @@ func HolderConsumerFor(node, module string, seat DeclaredSeat) (Consumer, bool)
 		Queue:          "holders",
 		AckWaitSeconds: 60,
 		MaxDeliver:     5,
+		// **One in flight.** A holder works one ask at a time, so the server hands it one at a
+		// time: with the default of many, every ask behind the one being worked was delivered,
+		// left unacknowledged for the length of the work, redelivered after the ack wait, and
+		// after the fifth time dropped — on 2026-10-01 twenty-six of forty-three builds asked in
+		// two minutes were never built, and the queue read as empty (novox/hq issue 186).
+		MaxAckPending: 1,
 		Why: fmt.Sprintf("%s on %s holds %s; it acknowledges after the work is done, so a "+
-			"crash mid-work redelivers rather than loses", module, node, seat.Name),
+			"crash mid-work redelivers rather than loses; one in flight, so a queue of asks is a "+
+			"queue and not a race against the ack wait", module, node, seat.Name),
 	}, true
 }
 

internal/broker/derived_test.go

@@ -153,3 +153,16 @@ func TestANodesDeclarationConsumerIsWhatItsOwnGrantAllows(t *testing.T) {
 	has(t, perms.Publish, "$JS.ACK.NODES."+c.Name+".>")
 	has(t, perms.Subscribe, c.Filters[0])
 }
+
+// A holder works one ask at a time, so the server hands it one at a time (novox/hq issue 186):
+// asks queued behind the one being worked wait in the stream rather than being delivered,
+// left to expire and dropped after the fifth redelivery.
+func TestAHoldersWorkerTakesOneAskAtATime(t *testing.T) {
+	c, found := HolderConsumerFor("anchor", "builder", DeclaredSeat{Name: "mesh-build-machine", Accepts: []string{"build"}})
+	if !found {
+		t.Fatal("a seat that accepts work has no worker")
+	}
+	if c.MaxAckPending != 1 {
+		t.Fatalf("the worker may have %d asks in flight; one, so a queue is a queue", c.MaxAckPending)
+	}
+}

internal/broker/jetstream.go

@@ -144,6 +144,7 @@ func (j *JetStream) EnsureStream(s Stream) error {
 		MaxMsgsPerSubject: int64(s.MaxMsgsPerSubject),
 		Description:       s.Why,
 	}
+	want.AllowDirect = s.Direct
 	if s.Retention == RetentionLastPerSubject {
 		// Last-per-subject is a limits stream with one message kept per subject, not a
 		// retention policy of its own — the state shape, spelled the way the server spells it.

internal/broker/membership.go

@@ -0,0 +1,131 @@
+package broker
+
+import (
+	"sort"
+	"strings"
+)
+
+// What the mesh issues an assignment to serve and to reach (novox/hq ADR 0160).
+//
+// A module's code names its tools and its events; **where they land is the mesh's to decide**, and
+// it decided it twice — once in the runtime, once here, by one rule compiled into both. Now the
+// controller composes a membership for every module on every machine and publishes it to a subject
+// only that assignment reads; the runtime serves exactly what the membership says, and the account's
+// grant is the same composition read the other way. The shape issued today is the shape the mesh
+// already had, so nothing moves when a membership first arrives; only who decides it moves.
+
+// Membership is one assignment's subjects: what this instance of a module on this machine serves,
+// and what it may reach.
+type Membership struct {
+	Node   string `json:"node"`
+	Module string `json:"module"`
+	// Serves is every address a tool of this instance answers on. `{tool}` stands for the tool's
+	// own name, which the module knows and the mesh does not need to: the mesh issues the address,
+	// the runtime fills the name. An address with a queue is shared with the module's other
+	// instances, and the bus hands each call to one of them; an address without is this instance's.
+	Serves []Served `json:"serves"`
+	// Seats is every verb of a seat this instance holds, at the subject the seat's callers use.
+	Seats []SeatServed `json:"seats,omitempty"`
+	// Emits is where an event of this module lands; `{event}` stands for the event's name.
+	Emits string `json:"emits"`
+	// Reaches is each tool this module may call, `<module>.<tool>`, to the subjects that reach it:
+	// the first is whichever instance answers, when the mesh issued one; the rest name a machine.
+	Reaches map[string][]string `json:"reaches,omitempty"`
+	// Tools is where this instance answers what it serves — the runtime's one verb of its own.
+	Tools string `json:"tools"`
+}
+
+// Served is one address a tool is answered on.
+type Served struct {
+	Subject string `json:"subject"`
+	Queue   string `json:"queue,omitempty"`
+}
+
+// SeatServed is one verb of a held seat, where its callers ask.
+type SeatServed struct {
+	Seat    string `json:"seat"`
+	Verb    string `json:"verb"`
+	Subject string `json:"subject"`
+}
+
+// MembershipSubject is the one address a runtime derives for itself: where its own membership is
+// published, from the two names its credential carries. Everything else is in the membership.
+func MembershipSubject(node, module string) string {
+	return "mesh.assignment." + node + "." + module
+}
+
+// Placements is where every module runs, for deciding which instance answers for the module.
+type Placements struct {
+	// Nodes is each module's machines.
+	Nodes map[string][]string
+	// Interchangeable is each module whose definition says its instances are the same anywhere,
+	// so the module's plain subject is issued to all of them in one queue.
+	Interchangeable map[string]bool
+}
+
+// AnswersForTheModule says whether an instance of a module on one machine is issued the module's
+// plain subject: when it is the only instance, or when the definition says instances are
+// interchangeable. A stateful module on two machines gets only its machines' subjects, so a call
+// that names none reaches nothing rather than the wrong store.
+func (p Placements) AnswersForTheModule(module string) bool {
+	return len(p.Nodes[module]) <= 1 || p.Interchangeable[module]
+}
+
+// MembershipFor composes one assignment's membership from what it declared and where everything
+// runs. The subjects are the ones PermissionsFor grants, derived here once more only until the
+// grant itself is read from the membership — which is the next step, not this one.
+func MembershipFor(node string, d Declared, where Placements) Membership {
+	own := "mesh.mod." + d.Module
+	m := Membership{
+		Node: node, Module: d.Module,
+		Emits: own + ".event.{event}",
+		Tools: own + ".tool.tools",
+	}
+	// This machine's address always; the module's when this instance answers for the module.
+	m.Serves = append(m.Serves, Served{Subject: own + ".tool.{tool}." + node})
+	if where.AnswersForTheModule(d.Module) {
+		m.Serves = append(m.Serves, Served{Subject: own + ".tool.{tool}", Queue: "serve." + d.Module})
+	}
+	for _, s := range d.Holds {
+		for _, verb := range s.Serves {
+			m.Seats = append(m.Seats, SeatServed{Seat: s.Name, Verb: verb, Subject: seatToolSubject(s, verb, node)})
+		}
+	}
+	if len(d.Invokes) > 0 {
+		m.Reaches = map[string][]string{}
+		for _, t := range d.Invokes {
+			if t == "*" || strings.HasPrefix(t, "seat:") {
+				continue // every tool, or a role's: addressed by name, not resolved per instance
+			}
+			module, tool, ok := strings.Cut(t, ".")
+			if !ok {
+				continue
+			}
+			var reach []string
+			if where.AnswersForTheModule(module) {
+				reach = append(reach, "mesh.mod."+module+".tool."+tool)
+			}
+			nodes := append([]string{}, where.Nodes[module]...)
+			sort.Strings(nodes)
+			for _, n := range nodes {
+				reach = append(reach, "mesh.mod."+module+".tool."+tool+"."+n)
+			}
+			m.Reaches[t] = reach
+		}
+	}
+	return m
+}
+
+// PlacementsOf reads where everything runs from the records the bus's accounts are composed from.
+func PlacementsOf(r Records, interchangeable map[string]bool) Placements {
+	p := Placements{Nodes: map[string][]string{}, Interchangeable: interchangeable}
+	for node, declared := range r.Assigned {
+		for _, d := range declared {
+			p.Nodes[d.Module] = append(p.Nodes[d.Module], node)
+		}
+	}
+	for _, nodes := range p.Nodes {
+		sort.Strings(nodes)
+	}
+	return p
+}

internal/broker/membership_test.go

@@ -0,0 +1,75 @@
+package broker
+
+import (
+	"reflect"
+	"testing"
+)
+
+// The mesh issues an assignment's subjects (novox/hq ADR 0160): a module alone on one machine
+// answers for the module and for its machine; a stateful module on two machines answers only for
+// each machine; one that says its instances are interchangeable answers for the module everywhere;
+// a holder serves its seat's verbs; and what a module may reach is resolved the same way.
+func TestAMembershipIsIssuedFromWhereEverythingRuns(t *testing.T) {
+	records := Records{Assigned: map[string][]Declared{
+		"anchor": {
+			{Module: "postgres", Serves: []string{"query"}, Holds: []Seat{{Name: "mesh-store", Scope: "mesh", Serves: []string{"databases", "query"}}}},
+			{Module: "catalog", Invokes: []string{"postgres.query", "search.find"}},
+		},
+		"home-server": {
+			{Module: "postgres"},
+			{Module: "search"},
+			{Module: "dashboard", Invokes: []string{"postgres.query"}},
+		},
+		"laptop": {{Module: "search"}},
+	}, Interchangeable: map[string]bool{"search": true}}
+	where := PlacementsOf(records, records.Interchangeable)
+
+	pg := MembershipFor("anchor", records.Assigned["anchor"][0], where)
+	if !reflect.DeepEqual(pg.Serves, []Served{{Subject: "mesh.mod.postgres.tool.{tool}.anchor"}}) {
+		t.Fatalf("a stateful module on two machines answers only for its machine: %+v", pg.Serves)
+	}
+	if len(pg.Seats) != 2 || pg.Seats[0].Subject != "mesh.seat.mesh-store.tool.databases" {
+		t.Fatalf("the holder serves the seat's verbs at the seat's subjects: %+v", pg.Seats)
+	}
+	if pg.Emits != "mesh.mod.postgres.event.{event}" || pg.Tools != "mesh.mod.postgres.tool.tools" {
+		t.Fatalf("events and the tools verb: %+v", pg)
+	}
+
+	search := MembershipFor("laptop", records.Assigned["laptop"][0], where)
+	if !reflect.DeepEqual(search.Serves, []Served{
+		{Subject: "mesh.mod.search.tool.{tool}.laptop"},
+		{Subject: "mesh.mod.search.tool.{tool}", Queue: "serve.search"},
+	}) {
+		t.Fatalf("an interchangeable module answers for the module in the queue too: %+v", search.Serves)
+	}
+
+	dashboard := MembershipFor("home-server", records.Assigned["home-server"][2], where)
+	if !reflect.DeepEqual(dashboard.Serves, []Served{
+		{Subject: "mesh.mod.dashboard.tool.{tool}.home-server"},
+		{Subject: "mesh.mod.dashboard.tool.{tool}", Queue: "serve.dashboard"},
+	}) {
+		t.Fatalf("a module alone on one machine answers for the module: %+v", dashboard.Serves)
+	}
+	if !reflect.DeepEqual(dashboard.Reaches["postgres.query"],
+		[]string{"mesh.mod.postgres.tool.query.anchor", "mesh.mod.postgres.tool.query.home-server"}) {
+		t.Fatalf("reaching a stateful module names each machine and no plain subject: %v", dashboard.Reaches)
+	}
+	catalog := MembershipFor("anchor", records.Assigned["anchor"][1], where)
+	if !reflect.DeepEqual(catalog.Reaches["search.find"],
+		[]string{"mesh.mod.search.tool.find", "mesh.mod.search.tool.find.home-server", "mesh.mod.search.tool.find.laptop"}) {
+		t.Fatalf("reaching an interchangeable module offers the plain subject first: %v", catalog.Reaches)
+	}
+	if MembershipSubject("anchor", "postgres") != "mesh.assignment.anchor.postgres" {
+		t.Fatal("the one subject a runtime derives for itself")
+	}
+}
+
+func TestAnAccountMayReadItsOwnMembershipAndNoOthers(t *testing.T) {
+	perms, err := PermissionsFor(Principal{Kind: KindModule, Node: "anchor", Module: "postgres", PasswordHash: "x"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	has(t, perms.Subscribe, "mesh.assignment.anchor.postgres")
+	has(t, perms.Publish, "$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.anchor.postgres")
+	hasNot(t, perms.Subscribe, "mesh.assignment.>")
+}

internal/broker/nats.go

@@ -173,8 +173,10 @@ func PermissionsFor(p Principal) (Permissions, error) {
 	switch p.Kind {
 	case KindController:
 		// The controller owns the mesh's own traffic and the streams. It is the only writer of
-		// stream definitions (design 25 §3), so it alone reaches the JetStream API.
+		// stream definitions (design 25 §3), so it alone reaches the JetStream API — and it alone
-		pub = []string{"mesh.control.>", "mesh.node.>", "$JS.API.>"}
+		// issues memberships (novox/hq ADR 0160), which it publishes into the assignments stream
+		// after each push; refused by the server on 2026-10-01 until this line named them.
+		pub = []string{"mesh.control.>", "mesh.node.>", "mesh.assignment.>", "$JS.API.>"}
 		// **And where its consumers deliver.** A push consumer delivers on `_DELIVER.<its name>`,
 		// and a client bound to it subscribes exactly that; the server refused it for every
 		// principal the first time one bound a consumer (2026-09-28). Each kind below is granted
@@ -298,6 +300,10 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		// away — no other principal may subscribe this namespace, and a caller's authority is
 		// still granted per tool, by name, on the publish side.
 		sub = append(sub, own+".tool.>")
+		// Its own membership (ADR 0160): the one subject a runtime derives for itself, read
+		// directly from the stream and followed live. Nothing else's.
+		sub = append(sub, MembershipSubject(p.Node, p.Module))
+		pub = append(pub, "$JS.API.DIRECT.GET."+AssignmentsStream+"."+MembershipSubject(p.Node, p.Module))
 
 		// 1b. The tools it calls, if its manifest says it calls any (novox/hq ADR 0152). The same
 		//     grant a person gets and derived the same way, so "what may this module ask" is

internal/broker/streams.go

@@ -47,8 +47,14 @@ type Stream struct {
 	// Why is carried into the assertion so an operator reading the server's own state finds the
 	// reason there, rather than only in a repository they may not have.
 	Why string
+	// Direct lets a client read a subject's last message without a consumer, which is how a
+	// runtime reads its own membership with no JetStream API beyond one request (ADR 0160).
+	Direct bool
 }
 
+// AssignmentsStream holds every assignment's membership, the newest per subject.
+const AssignmentsStream = "ASSIGNMENTS"
+
 // MeshStreams is the foundation set, in the order a person reads it.
 //
 // **CONTROL names its subjects rather than taking `mesh.control.>`**, because heartbeats live
@@ -78,6 +84,14 @@ func MeshStreams() []Stream {
 			Why: "one declaration per node, always the newest; a node that sees sequence n refuses " +
 				"n-1 by construction (issue 107)",
 		},
+		{
+			Name:      AssignmentsStream,
+			Subjects:  []string{"mesh.assignment.*.*"},
+			Retention: RetentionLastPerSubject,
+			Direct:    true,
+			Why: "one membership per assignment, always the newest: what the mesh issued this module " +
+				"on this machine to serve and to reach (ADR 0160); read directly by the runtime it is for",
+		},
 		{
 			Name: EventsStream,
 			// A seat's own events ride here too: they are 1:many like any event, and the

internal/broker/streams_test.go

@@ -126,6 +126,7 @@ func TestEachStreamCarriesTheRetentionItsShapeNeeds(t *testing.T) {
 		"CONTROL":     RetentionWorkQueue,
 		"NODES":       RetentionLastPerSubject,
 		"EVENTS":      RetentionLimits,
+		"ASSIGNMENTS": RetentionLastPerSubject,
 	}
 	got := map[string]Retention{}
 	for _, s := range MeshStreams() {

internal/broker/testdata/composed.conf

@@ -24,7 +24,7 @@ accounts {
     jetstream: enabled
     users = [
       { user: "controller", password: "$2a$11$cccccccccccccccccccccc", permissions: {
-        publish: { allow: ["$JS.ACK.CONTROL.controller.>", "$JS.ACK.EVENTS.controller.>", "$JS.API.>", "_INBOX.enrol.>", "mesh.control.>", "mesh.mod.*.tool.>", "mesh.node.>", "mesh.seat.mesh-build-machine.accept.>", "mesh.seat.mesh-controller.event.applied", "mesh.seat.mesh-controller.event.built-before", "mesh.seat.mesh-controller.event.refused"] }
+        publish: { allow: ["$JS.ACK.CONTROL.controller.>", "$JS.ACK.EVENTS.controller.>", "$JS.API.>", "_INBOX.enrol.>", "mesh.assignment.>", "mesh.control.>", "mesh.mod.*.tool.>", "mesh.node.>", "mesh.seat.mesh-build-machine.accept.>", "mesh.seat.mesh-controller.event.applied", "mesh.seat.mesh-controller.event.built-before", "mesh.seat.mesh-controller.event.refused"] }
         subscribe: { allow: ["$JS.API.>", "_DELIVER.controller", "_DELIVER.controller.>", "_INBOX.controller.>", "mesh.control.>", "mesh.mod.gitea.event.pull.merged", "mesh.mod.mesh-catalog.event.catching-up", "mesh.mod.mesh-catalog.event.upgraded", "mesh.seat.mesh-build-machine.event.built", "mesh.seat.mesh-controller.tool.>"] }
         allow_responses: { max: 1, ttl: "1m" }
       } }
@@ -37,18 +37,18 @@ accounts {
         subscribe: { allow: ["_DELIVER.one", "_DELIVER.one.>", "_INBOX.node.one.>", "mesh.node.one.declare"] }
       } }
       { user: "one.telegram", password: "$2a$11$tttttttttttttttttttttt", permissions: {
-        publish: { allow: ["$JS.ACK.EVENTS.one_telegram.>", "$JS.ACK.SEAT_TELEGRAM_SENDER.SEAT_TELEGRAM_SENDER_worker.>", "$JS.API.CONSUMER.INFO.EVENTS.one_telegram", "$JS.API.CONSUMER.INFO.SEAT_TELEGRAM_SENDER.SEAT_TELEGRAM_SENDER_worker", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.one_telegram", "mesh.seat.telegram-sender.event.delivered", "mesh.seat.telegram-sender.event.failed"] }
+        publish: { allow: ["$JS.ACK.EVENTS.one_telegram.>", "$JS.ACK.SEAT_TELEGRAM_SENDER.SEAT_TELEGRAM_SENDER_worker.>", "$JS.API.CONSUMER.INFO.EVENTS.one_telegram", "$JS.API.CONSUMER.INFO.SEAT_TELEGRAM_SENDER.SEAT_TELEGRAM_SENDER_worker", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.one_telegram", "$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.one.telegram", "mesh.seat.telegram-sender.event.delivered", "mesh.seat.telegram-sender.event.failed"] }
-        subscribe: { allow: ["_DELIVER.SEAT_TELEGRAM_SENDER_worker", "_DELIVER.SEAT_TELEGRAM_SENDER_worker.>", "_INBOX.one.telegram.>", "mesh.mod.telegram.tool.>", "mesh.seat.telegram-sender.accept.send"] }
+        subscribe: { allow: ["_DELIVER.SEAT_TELEGRAM_SENDER_worker", "_DELIVER.SEAT_TELEGRAM_SENDER_worker.>", "_INBOX.one.telegram.>", "mesh.assignment.one.telegram", "mesh.mod.telegram.tool.>", "mesh.seat.telegram-sender.accept.send"] }
         allow_responses: { max: 1, ttl: "1m" }
       } }
       { user: "two.audit", password: "$2a$11$aaaaaaaaaaaaaaaaaaaaaa", permissions: {
-        publish: { allow: ["$JS.ACK.EVENTS.two_audit.>", "$JS.API.CONSUMER.INFO.EVENTS.two_audit", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.two_audit"] }
+        publish: { allow: ["$JS.ACK.EVENTS.two_audit.>", "$JS.API.CONSUMER.INFO.EVENTS.two_audit", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.two_audit", "$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.two.audit"] }
-        subscribe: { allow: ["_INBOX.two.audit.>", "mesh.mod.audit.tool.>", "mesh.mod.shop.event.order.placed"] }
+        subscribe: { allow: ["_INBOX.two.audit.>", "mesh.assignment.two.audit", "mesh.mod.audit.tool.>", "mesh.mod.shop.event.order.placed"] }
         allow_responses: { max: 1, ttl: "1m" }
       } }
       { user: "two.shop", password: "$2a$11$ssssssssssssssssssssss", permissions: {
-        publish: { allow: ["$JS.ACK.EVENTS.two_shop.>", "$JS.API.CONSUMER.INFO.EVENTS.two_shop", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.two_shop", "mesh.mod.shop.event.order.placed", "mesh.seat.telegram-sender.accept.send"] }
+        publish: { allow: ["$JS.ACK.EVENTS.two_shop.>", "$JS.API.CONSUMER.INFO.EVENTS.two_shop", "$JS.API.CONSUMER.MSG.NEXT.EVENTS.two_shop", "$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.two.shop", "mesh.mod.shop.event.order.placed", "mesh.seat.telegram-sender.accept.send"] }
-        subscribe: { allow: ["_INBOX.two.shop.>", "mesh.mod.shop.tool.>"] }
+        subscribe: { allow: ["_INBOX.two.shop.>", "mesh.assignment.two.shop", "mesh.mod.shop.tool.>"] }
         allow_responses: { max: 1, ttl: "1m" }
       } }
     ]

internal/broker/users.go

@@ -47,6 +47,9 @@ type Records struct {
 	Enrolling []string
 	// People is each person's name against the tools they may invoke, `*` for an administrator.
 	People map[string][]string
+	// Interchangeable is each module whose definition says its instances are the same anywhere
+	// (ADR 0160), which decides whether the module's plain subject is issued to every instance.
+	Interchangeable map[string]bool
 }
 
 // Users is every user the composed file should contain, in the order it will be written.

internal/catalogue/brokered_test.go

@@ -25,7 +25,7 @@ func reachable() Node {
 func onNetwork(nodes ...string) map[string][]Provider {
 	out := make([]Provider, 0, len(nodes))
 	for _, n := range nodes {
-		out = append(out, Provider{Node: n, At: n + ".internal"})
+		out = append(out, Provider{Node: n, At: n + ".internal", Module: "postgres"})
 	}
 	return map[string][]Provider{"postgres-database": out}
 }
@@ -99,7 +99,7 @@ func TestSayingWhichOneSettlesIt(t *testing.T) {
 	got, err := Resolve(brokeredShelf(), []string{"meshboard"}, reachable(),
 		World{
 			Offered: onNetwork("anchor", "archive"),
-			Pinned:  map[string]string{"postgres-database": "archive"},
+			Pinned:  map[string]Chosen{"postgres-database": {Node: "archive", Module: "postgres"}},
 		})
 	if err != nil {
 		t.Fatal(err)
@@ -115,7 +115,7 @@ func TestBeingPointedAtAMachineThatDoesNotProvideItIsRefused(t *testing.T) {
 	_, err := Resolve(brokeredShelf(), []string{"meshboard"}, reachable(),
 		World{
 			Offered: onNetwork("anchor", "archive"),
-			Pinned:  map[string]string{"postgres-database": "somewhere-else"},
+			Pinned:  map[string]Chosen{"postgres-database": {Node: "somewhere-else", Module: "postgres"}},
 		})
 	if err == nil {
 		t.Fatal("a machine was silently given a different database from the one chosen")
@@ -131,12 +131,12 @@ func TestOneProviderDoesNotOverruleAChoice(t *testing.T) {
 	_, err := Resolve(brokeredShelf(), []string{"meshboard"}, reachable(),
 		World{
 			Offered: onNetwork("anchor"),
-			Pinned:  map[string]string{"postgres-database": "archive"},
+			Pinned:  map[string]Chosen{"postgres-database": {Node: "archive", Module: "postgres"}},
 		})
 	if err == nil {
 		t.Fatal("the only database was used although another was chosen")
 	}
-	if !strings.Contains(err.Error(), "only anchor provides it") {
+	if !strings.Contains(err.Error(), "only anchor/postgres provides it") {
 		t.Fatalf("the refusal does not say what is available: %v", err)
 	}
 }

internal/catalogue/chosen.go

@@ -0,0 +1,100 @@
+package catalogue
+
+import (
+	"sort"
+)
+
+// Chosen is the provider somebody named for a provision: the module, and the node it runs on. Both,
+// always (novox/hq #258) — a provision comes from a module, and the same module on two machines is
+// two answers, so neither half alone says which. Module is empty only on a record made before this
+// was asked, and such a record is honoured exactly as long as it is unambiguous.
+type Chosen struct {
+	Node   string
+	Module string
+}
+
+func (c Chosen) String() string {
+	if c.Module == "" {
+		return c.Node
+	}
+	return c.Node + "/" + c.Module
+}
+
+// matches is whether this provider is the one chosen.
+func (c Chosen) matches(p Provider) bool {
+	return p.Node == c.Node && (c.Module == "" || p.Module == c.Module)
+}
+
+// among is every offered provider the choice names — one, when the choice is whole.
+func (c Chosen) among(where []Provider) []Provider {
+	var out []Provider
+	for _, p := range where {
+		if c.matches(p) {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// nameOf is how a refusal names a provider: the node and the module on it.
+func nameOf(p Provider) string {
+	return Chosen{Node: p.Node, Module: p.Module}.String()
+}
+
+// providerNames is every provider named, sorted, for a refusal to list.
+func providerNames(where []Provider) []string {
+	out := make([]string, 0, len(where))
+	for _, p := range where {
+		out = append(out, nameOf(p))
+	}
+	sort.Strings(out)
+	return out
+}
+
+// providersHere is which modules in this node's own set offer a provision, sorted.
+func providersHere(catalogue map[string]Manifest, here func(string) bool, want string) []string {
+	var out []string
+	for name, m := range catalogue {
+		if !here(name) {
+			continue
+		}
+		for _, o := range m.Offers() {
+			if o == want {
+				out = append(out, name)
+				break
+			}
+		}
+	}
+	sort.Strings(out)
+	return out
+}
+
+// servedByOne is what one provider beside the consumer says a consumer needs to know, or nothing.
+//
+// Serving is *whether* a need is created at all when the provider is on this same machine (novox/hq
+// 04-ISSUES/038's sibling): a need never created is a binding the consumer never gets. The manifest
+// alone answers that; the values are settled later, with the node's settings.
+func servedByOne(m Manifest, want string) map[string]any {
+	if _, ok := m.Serves[want]; ok {
+		return ServedOn(m, want, nil)
+	}
+	return nil
+}
+
+// sharedByOne is the own secret that provider names as its credential (ADR 0158), or "" when it
+// gives each consumer its own.
+func sharedByOne(m Manifest, want string) string {
+	if own, shared := m.SharedCredentialOf(want); shared {
+		return own
+	}
+	return ""
+}
+
+func oneOf(list []string, s string) bool {
+	for _, x := range list {
+		if x == s {
+			return true
+		}
+	}
+	return false
+}

internal/catalogue/holdings_test.go

@@ -107,6 +107,27 @@ func TestCanHoldJudgesClaimScopeAndWhatTheSeatDelivers(t *testing.T) {
 	if err := CanHold(cannotAnswer, seat); err == nil || !strings.Contains(err.Error(), `does not provide "mesh-bus"`) {
 		t.Fatalf("a holder that cannot answer for the seat was allowed: %v", err)
 	}
+	// A holder's own tools need not be the seat's verbs: the claim may name what it serves for the
+	// role (ADR 0160), and then only those count — and only the seat's verbs may be named.
+	promising := seat
+	promising.Serves = []Verb{{Name: "databases"}, {Name: "query"}}
+	engine := newBroker()
+	engine.Tools = []string{"engine_list_databases", "engine_query"}
+	if err := CanHold(engine, promising); err == nil || !strings.Contains(err.Error(), "does not serve databases, query") {
+		t.Fatalf("a holder whose tools are not the seat's verbs was allowed without saying what it serves: %v", err)
+	}
+	engine.Claims[0].Serves = []string{"databases", "query"}
+	if err := CanHold(engine, promising); err != nil {
+		t.Fatalf("a claim naming the seat's verbs was refused: %v", err)
+	}
+	engine.Claims[0].Serves = []string{"databases"}
+	if err := CanHold(engine, promising); err == nil || !strings.Contains(err.Error(), "does not serve query") {
+		t.Fatalf("a claim naming half the verbs was allowed: %v", err)
+	}
+	engine.Claims[0].Serves = []string{"databases", "query", "engine_query"}
+	if err := CanHold(engine, promising); err == nil || !strings.Contains(err.Error(), "does not promise") {
+		t.Fatalf("a claim naming a verb the seat never promised was allowed: %v", err)
+	}
 	// And the judgement follows the store's row, not a compiled copy.
 	busSeatDelivering(t, "amqp")
 	seat, _ = SeatNamed("mesh-broker")

internal/catalogue/manifest.go

@@ -52,6 +52,22 @@ type Claim struct {
 	Name string `json:"name"`
 	// Scope defaults to the node, which is where nearly everything singular is singular.
 	Scope string `json:"scope,omitempty"`
+	// Serves names the seat's verbs this module implements for the role, when its own tools are
+	// not the seat's (novox/hq ADR 0159, 0160): the store's `databases` is not postgres's
+	// `postgres_list_databases`, and a holder may well serve both. The runtime serves an
+	// implementation registered under the seat's name on the seat's subjects. Absent, the
+	// module's own `tools` must list every verb the seat promises, which is how a module named
+	// like its seat — the catalogue, the records — says they are one and the same.
+	Serves []string `json:"serves,omitempty"`
+}
+
+// ServesFor is what this claim offers a seat's protocol: the verbs it names, else the module's
+// own tools.
+func (c Claim) ServesFor(m Manifest) []string {
+	if len(c.Serves) > 0 {
+		return c.Serves
+	}
+	return m.Tools
 }
 
 // At is this claim's scope, with the default applied.
@@ -293,6 +309,12 @@ type Manifest struct {
 	// module claiming a seat answers what that seat's protocol promises (novox/hq ADR 0118).
 	Tools []string `json:"tools,omitempty"`
 
+	// Instances says whether this module's instances are the same anywhere — `interchangeable` —
+	// so a call that names no machine may be answered by any of them (novox/hq ADR 0160). A fact
+	// about the software, not about the bus: a stateless web tool says it; a database does not,
+	// and its instances are then each addressed by machine, never confused for one another.
+	Instances string `json:"instances,omitempty"`
+
 	// Invokes are the tools this module calls, each `<module>.<tool>` or a role's `seat:<seat>.<verb>`,
 	// or the single entry `*` for every tool on the mesh (novox/hq ADR 0152, ADR 0154).
 	//
@@ -1173,6 +1195,11 @@ func ParseManifest(raw []byte) (Manifest, error) {
 				m.Module, r))
 		}
 	}
+	if m.Instances != "" && m.Instances != InstancesInterchangeable {
+		problems = append(problems, fmt.Sprintf(
+			"%s says its instances are %q; the one word is %q, for a module that is the same on every machine",
+			m.Module, m.Instances, InstancesInterchangeable))
+	}
 	for _, offer := range m.Provides {
 		p := offer.Name
 		if !name.MatchString(p) {
@@ -1960,3 +1987,7 @@ func (o OwnSecrets) Paths() map[string]string {
 	}
 	return out
 }
+
+// InstancesInterchangeable is the one value of a definition's `instances`: the module is the same
+// on every machine, so any instance may answer for the module.
+const InstancesInterchangeable = "interchangeable"

internal/catalogue/pin_names_module_test.go

@@ -0,0 +1,115 @@
+package catalogue
+
+import (
+	"strings"
+	"testing"
+)
+
+// Two modules on one node both provide acme-ca — public-acme (Let's Encrypt) and step-ca (the
+// mesh's own authority) on novox — and a route-proxy elsewhere must get the public one (novox/hq
+// #258). A pin names the module as well as the node, so that it can say which.
+
+func issuerShelf() map[string]Manifest {
+	return shelf(
+		Manifest{Module: "public-acme", Version: "1", Provides: FromAnywhere("acme-ca"),
+			Serves: map[string]map[string]any{"acme-ca": {"at": "acme-v02.api.letsencrypt.org"}}},
+		Manifest{Module: "step-ca", Version: "1", Provides: FromAnywhere("acme-ca"),
+			Serves: map[string]map[string]any{"acme-ca": {"at": "novox.internal"}}},
+		Manifest{Module: "route-proxy", Version: "1", Requires: []string{"acme-ca"}},
+	)
+}
+
+func twoIssuersOnOneNode() map[string][]Provider {
+	return map[string][]Provider{"acme-ca": {
+		{Node: "novox", At: "novox.internal", Module: "public-acme", Serves: map[string]any{"at": "acme-v02.api.letsencrypt.org"}},
+		{Node: "novox", At: "novox.internal", Module: "step-ca", Serves: map[string]any{"at": "novox.internal"}},
+	}}
+}
+
+func TestTwoProvidersOnOneNodeAreRefusedWithBothNamed(t *testing.T) {
+	// The refusal must name the pair, because a node alone cannot tell them apart.
+	_, err := Resolve(issuerShelf(), []string{"route-proxy"}, reachable(),
+		World{Offered: twoIssuersOnOneNode()})
+	if err == nil {
+		t.Fatal("two providers on one node were resolved by picking")
+	}
+	for _, want := range []string{"novox/public-acme", "novox/step-ca", "<node> <module>"} {
+		if !strings.Contains(err.Error(), want) {
+			t.Fatalf("the refusal does not say %q: %v", want, err)
+		}
+	}
+}
+
+func TestAPinNamesTheModule(t *testing.T) {
+	got, err := Resolve(issuerShelf(), []string{"route-proxy"}, reachable(),
+		World{Offered: twoIssuersOnOneNode(),
+			Pinned: map[string]Chosen{"acme-ca": {Node: "novox", Module: "public-acme"}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got.Needs) != 1 || got.Needs[0].From != "novox" || got.Needs[0].Serves["at"] != "acme-v02.api.letsencrypt.org" {
+		t.Fatalf("the named module was not the one taken: %+v", got.Needs)
+	}
+}
+
+func TestARecordNamingOnlyTheNodeIsRefusedWhenThatNodeAnswersTwice(t *testing.T) {
+	// A pin from before the module was asked for. It once took the last one listed — a coin flip.
+	_, err := Resolve(issuerShelf(), []string{"route-proxy"}, reachable(),
+		World{Offered: twoIssuersOnOneNode(), Pinned: map[string]Chosen{"acme-ca": {Node: "novox"}}})
+	if err == nil {
+		t.Fatal("a node that answers twice was resolved by picking")
+	}
+	if !strings.Contains(err.Error(), "provides it 2 times") || !strings.Contains(err.Error(), "pin workstation acme-ca novox <module>") {
+		t.Fatalf("the refusal does not ask for the module: %v", err)
+	}
+}
+
+func TestAPinNamingAModuleThatDoesNotProvideItIsRefused(t *testing.T) {
+	_, err := Resolve(issuerShelf(), []string{"route-proxy"}, reachable(),
+		World{Offered: twoIssuersOnOneNode(), Pinned: map[string]Chosen{"acme-ca": {Node: "novox", Module: "gitea"}}})
+	if err == nil || !strings.Contains(err.Error(), "novox/gitea does not provide it") {
+		t.Fatalf("a module that does not provide it was not refused by name: %v", err)
+	}
+}
+
+func TestTwoProvidersBesideTheConsumerAreRefusedUntilOneIsNamed(t *testing.T) {
+	// The same ambiguity on the consumer's own machine. This was settled by a map walk — random,
+	// per plan — which is how novox's own proxy got its issuer.
+	_, err := Resolve(issuerShelf(), []string{"route-proxy", "public-acme", "step-ca"}, reachable(), World{})
+	if err == nil {
+		t.Fatal("two providers beside the consumer were resolved by picking")
+	}
+	if !strings.Contains(err.Error(), "workstation provides \"acme-ca\" 2 times") || !strings.Contains(err.Error(), "public-acme, step-ca") {
+		t.Fatalf("the refusal does not list them: %v", err)
+	}
+}
+
+func TestAPinSettlesTwoProvidersBesideTheConsumer(t *testing.T) {
+	got, err := Resolve(issuerShelf(), []string{"route-proxy", "public-acme", "step-ca"}, reachable(),
+		World{Pinned: map[string]Chosen{"acme-ca": {Node: "workstation", Module: "public-acme"}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var found bool
+	for _, n := range got.Needs {
+		if n.Name == "acme-ca" {
+			found = true
+			if n.Serves["at"] != "acme-v02.api.letsencrypt.org" {
+				t.Fatalf("the named module was not the one taken: %+v", n)
+			}
+		}
+	}
+	if !found {
+		t.Fatalf("no need for acme-ca was created: %+v", got.Needs)
+	}
+}
+
+func TestTheFirstPassDoesNotRefuseTwoProvidersBesideTheConsumer(t *testing.T) {
+	// The first pass answers only what a node offers. Refused there, the node vanishes from every
+	// other node's world — and the whole mesh loses its vault for an ambiguity one machine has to
+	// settle. The second pass is where it is refused, and the test above proves it is.
+	if _, err := Resolve(issuerShelf(), []string{"route-proxy", "public-acme", "step-ca"}, reachable(),
+		World{Unchecked: true}); err != nil {
+		t.Fatalf("the first pass refused what only the second may: %v", err)
+	}
+}

internal/catalogue/resolve.go

@@ -48,11 +48,12 @@ type World struct {
 	Holdings []Held
 	// Offered is what other nodes provide at mesh scope, and everything needed to use it.
 	Offered map[string][]Provider
-	// Pinned is which node this machine was told to get a provision from, by name. Only consulted
+	// Pinned is which provider this machine was told to get a provision from, by name: a module and
-	// when more than one node could answer -- a choice recorded before it was needed should not
+	// the node it runs on, both (novox/hq #258). Only consulted when more than one could answer -- a
-	// start meaning something the day a second provider appears, and one recorded and then made
+	// choice recorded before it was needed should not start meaning something the day a second
-	// unnecessary should not quietly stop applying either.
+	// provider appears, and one recorded and then made unnecessary should not quietly stop applying
-	Pinned map[string]string
+	// either.
+	Pinned map[string]Chosen
 	// Licences is every provision answered by a **record rather than a node**, by provision name.
 	//
 	// novox/hq ADR 0024: a hosted model is on nobody's machine and is reached over the public
@@ -260,6 +261,10 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 	// still "choose one" after somebody has chosen one. That makes the remedy useless, and it is
 	// how this read when first used.
 	satisfied := map[string]bool{}
+	// Which modules a person assigned here, hostable. The walk marks a module chosen only when it
+	// reaches it, and a consumer may be reached before the provider beside it — so the provider of
+	// something already satisfied is looked for among these as well as among the chosen.
+	assignedHere := map[string]bool{}
 
 	// Everything a person assigned goes in first, except what this machine cannot run. Those are
 	// choices already made, and a requirement one of them answers is not a choice to put back to
@@ -284,6 +289,7 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 			for _, o := range m.Offers() {
 				satisfied[o] = true
 			}
+			assignedHere[a] = true
 		}
 		because[a] = "assigned"
 		queue = append(queue, a)
@@ -311,6 +317,51 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 		// commonest arrangement of all — a service and its database on one node — the weakest
 		// handling, silently.
 		if satisfied[want] && !isModule(catalogue, want) {
+			here := func(name string) bool { return chosen[name] || assignedHere[name] }
+			local := providersHere(catalogue, here, want)
+			// Which of them it matters to choose between. A plain capability — a shell, a display
+			// server — asks nothing of whoever answers it, and three shells beside an editor are
+			// not a choice to put to anybody. One that grants a credential, or serves a fact the
+			// consumer cannot guess, becomes a binding, and a binding is to one provider.
+			matter := local
+			if !brokered[want] {
+				matter = nil
+				for _, name := range local {
+					if _, ok := catalogue[name].Serves[want]; ok {
+						matter = append(matter, name)
+					}
+				}
+			}
+			var by Manifest
+			switch len(matter) {
+			case 0:
+				// Nothing to bind to; satisfied by its presence, as it was.
+			case 1:
+				by = catalogue[matter[0]]
+			default:
+				// Two modules on this machine answer it. Taking whichever a map walk met first
+				// was the rule until novox/hq #258 — random, per plan — and the same stance as
+				// across machines applies: ambiguity is refused, never resolved by picking.
+				//
+				// **Not in the first pass.** That pass exists only to answer *what does this node
+				// offer*, and refusing there makes the machine vanish rather than report a problem
+				// (the sibling case below says why): every other node then loses what this one
+				// provides — the vault, the identity provider — and refuses for a fault that is
+				// this node's to settle. The second pass refuses it properly, where it is asked.
+				if world.Unchecked {
+					continue
+				}
+				c, pinned := world.Pinned[want]
+				if !pinned || c.Node != node.Name || !oneOf(matter, c.Module) {
+					reported[want] = true
+					problems = append(problems, fmt.Sprintf(
+						"%s provides %q %d times, wanted by %s — say which with `pin %s %s %s <module>`: %s",
+						node.Name, want, len(matter), because[want], node.Name, want, node.Name,
+						strings.Join(matter, ", ")))
+					continue
+				}
+				by = catalogue[c.Module]
+			}
 			if brokered[want] {
 				// Answered here, and still a need: the provider is this node.
 				//
@@ -326,9 +377,9 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 				}
 				needs = append(needs, Needed{
 					Name: want, From: node.Name, At: at,
-					Serves: servedHere(catalogue, chosen, want), For: because[want],
+					Serves: servedByOne(by, want), For: because[want],
-					SharedOwn: sharedHere(catalogue, chosen, want)})
+					SharedOwn: sharedByOne(by, want)})
-			} else if served := servedHere(catalogue, chosen, want); len(served) > 0 {
+			} else if served := servedByOne(by, want); len(served) > 0 {
 				// Answered here with no credential to mint, but the provider serves facts the
 				// consumer cannot guess — a port, a model name — and so still needs a binding.
 				// **The reachability rule does not apply**: both ends are on this same machine, so
@@ -358,11 +409,7 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 		if brokered[want] {
 			reported[want] = true
 			where := world.Offered[want]
-			names := make([]string, 0, len(where))
+			names := providerNames(where)
-			for _, p := range where {
-				names = append(names, p.Node)
-			}
-			sort.Strings(names)
 			take := func(p Provider) {
 				if node.At != "" && p.At == "" || node.At == "" && p.At != "" || node.At == "" && p.At == "" {
 					// One of them is not on the private network, so there is no path between
@@ -396,17 +443,17 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 					"nothing in this mesh provides %q, wanted by %s %s",
 					want, because[want], remedy))
 			case len(where) == 1:
-				if chosenNode, pinned := world.Pinned[want]; pinned && chosenNode != where[0].Node {
+				if c, pinned := world.Pinned[want]; pinned && !c.matches(where[0]) {
 					// One provider, and it is not the one this machine was told to use. Silently
 					// using the other would be the mesh overruling a choice somebody made.
 					problems = append(problems, fmt.Sprintf(
 						"%s was told to get %q from %s, and only %s provides it",
-						node.Name, want, chosenNode, where[0].Node))
+						node.Name, want, c, nameOf(where[0])))
 					break
 				}
 				take(where[0])
 			default:
-				chosenNode, pinned := world.Pinned[want]
+				c, pinned := world.Pinned[want]
 				if !pinned {
 					// **The seat's holder answers, when a seat delivers this** (novox/hq ADR 0110).
 					// Not a guess, which ADR 0009 refuses: the choice was made once, mesh-wide, by
@@ -418,27 +465,32 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 						break
 					}
 					problems = append(problems, fmt.Sprintf(
-						"%d nodes provide %q, wanted by %s — say which with `pin %s %s <node>`: %s",
+						"%d providers of %q, wanted by %s — say which with `pin %s %s <node> <module>`: %s",
 						len(where), want, because[want], node.Name, want,
 						strings.Join(names, ", ")))
 					break
 				}
-				var chosen *Provider
+				matching := c.among(where)
-				for i, w := range where {
+				switch len(matching) {
-					if w.Node == chosenNode {
+				case 0:
-						chosen = &where[i]
+					// Pointed at a provider that does not answer this. Refused rather than
-					}
-				}
-				if chosen == nil {
-					// Pointed at a machine that does not answer this. Refused rather than
 					// falling back to another: a fallback would quietly move somebody's data to
 					// a machine they did not choose, which is the whole reason this is asked.
 					problems = append(problems, fmt.Sprintf(
 						"%s was told to get %q from %s, and %s does not provide it — these do: %s",
-						node.Name, want, chosenNode, chosenNode, strings.Join(names, ", ")))
+						node.Name, want, c, c, strings.Join(names, ", ")))
-					break
+				case 1:
+					take(matching[0])
+				default:
+					// A record naming only the node, from before a pin named the module, and that
+					// node answers twice. This once took the last one listed (novox/hq #258): a
+					// coin flip, handed to whoever reads the certificate it chose.
+					problems = append(problems, fmt.Sprintf(
+						"%s was told to get %q from %s, and %s provides it %d times — say which with "+
+							"`pin %s %s %s <module>`: %s",
+						node.Name, want, c, c.Node, len(matching), node.Name, want, c.Node,
+						strings.Join(providerNames(matching), ", ")))
 				}
-				take(*chosen)
 			}
 			continue
 		}
@@ -597,31 +649,6 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 // need that is never created is a binding the consumer never gets. It is right about that from the
 // manifest alone, which is why walking the catalogue mid-resolution is enough here and is not
 // enough for the values.
-// sharedHere is the own secret the provider of a provision on this same machine names as its
-// credential (ADR 0158), or "" when the provider gives each consumer its own.
-func sharedHere(catalogue map[string]Manifest, chosen map[string]bool, want string) string {
-	for name, m := range catalogue {
-		if !chosen[name] {
-			continue
-		}
-		if own, shared := m.SharedCredentialOf(want); shared {
-			return own
-		}
-	}
-	return ""
-}
-
-func servedHere(catalogue map[string]Manifest, chosen map[string]bool, want string) map[string]any {
-	for name, m := range catalogue {
-		if !chosen[name] {
-			continue
-		}
-		if _, ok := m.Serves[want]; ok {
-			return ServedOn(m, want, nil)
-		}
-	}
-	return nil
-}
 
 // isModule reports whether a name is a module in its own right rather than only something
 // modules provide.

internal/catalogue/seats.go

@@ -59,13 +59,26 @@ var defaultSeats = []Seat{
 	{Name: ControllerSeatName, Scope: ScopeMesh, Decision: "novox/hq ADR 0079",
 		Emits:  []string{"applied", "refused", "built-before"},
 		Serves: ControllerVerbs},
-	{Name: "mesh-store", Scope: ScopeMesh, Delivers: "postgres-database", Decision: "novox/hq ADR 0079"},
+	// The store's first verbs (novox/hq ADR 0159): the smallest set that makes the store askable,
+	// served by whichever module holds the seat with tools of these names.
+	{Name: "mesh-store", Scope: ScopeMesh, Delivers: "postgres-database", Decision: "novox/hq ADR 0079",
+		Serves: []Verb{
+			{Name: "databases", Description: "Every database the store holds, with its on-disk size.",
+				Input: schema(map[string]string{}, nil)},
+			{Name: "query", Description: "One read-only statement against one database the store holds.",
+				Input: schema(map[string]string{"database": "the database to query", "sql": "the read-only statement"},
+					[]string{"database", "sql"})},
+		}},
 	// **Delivers the mesh's own bus, not `amqp`.** Those were the same word until
 	// ADR 0127 separated them: `amqp` is a backing service a module may require, and this seat is
 	// the mesh's own transport. ADR 0128 then made that connection something a module requires
 	// rather than receives ambiently — 23 of the catalogue's modules never speak, and an ambient
 	// connection would mint a credential for each.
 	{Name: "mesh-broker", Scope: ScopeMesh, Delivers: "mesh-bus", Decision: "novox/hq ADR 0079"},
+	// The vault: the controller seals every minted credential with what it provides, which is the
+	// test for a seat of the mesh's own (novox/hq ADR 0161) — a second provider of `secret` is a
+	// second claimant, refused by name, rather than a candidate for a pin.
+	{Name: "mesh-vault", Scope: ScopeMesh, Delivers: "secret", Decision: "novox/hq ADR 0161"},
 	// Named for its scope since 2026-09-30 (novox/hq ADR 0156); `the-artifact-store` resolves to it as
 	// an alias on a mesh that predates the rename. It serves artifacts of every kind a build makes —
 	// images and archives, by digest — which is why the provision is the artifact store and not an
@@ -286,11 +299,19 @@ func CanHold(m Manifest, seat Seat) error {
 	// **Serving the seat's tools is a condition of holding it** (novox/hq ADR 0132). A holder that
 	// does not answer what the role promises is every caller's timeout, found at registration and
 	// at handover instead, naming the verbs rather than the fact that something is missing.
-	if missing := unservedVerbs(m.Tools, seat.Serves); len(missing) > 0 {
+	if missing := unservedVerbs(claimed.ServesFor(m), seat.Serves); len(missing) > 0 {
 		return fmt.Errorf("%s claims %s but does not serve %s, which that seat's protocol promises "+
-			"(novox/hq ADR 0132) — a holder lists every verb its seat declares under tools",
+			"(novox/hq ADR 0132) — a holder names every verb its seat declares, under the claim's "+
+			"serves or among its own tools",
 			m.Module, seat.Name, strings.Join(missing, ", "))
 	}
+	// And nothing the seat does not promise: a verb named here that the protocol lacks is served
+	// to nobody, which is a typo the holder would otherwise discover as a caller's timeout.
+	if extra := unpromised(claimed.Serves, seat.Serves); len(extra) > 0 {
+		return fmt.Errorf("%s claims %s and says it serves %s, which that seat's protocol does not "+
+			"promise — a claim's serves names the seat's verbs and nothing else",
+			m.Module, seat.Name, strings.Join(extra, ", "))
+	}
 	return nil
 }
 

internal/catalogue/seats_declared.go

@@ -208,7 +208,7 @@ func CatalogueProblems(shelf Shelf) []string {
 			}
 			// A holder that does not answer what the seat promises is a caller's timeout, found
 			// at assignment instead.
-			if missing := unserved(m, s); len(missing) > 0 {
+			if missing := unserved(m, c, s); len(missing) > 0 {
 				problems = append(problems, fmt.Sprintf(
 					"%s claims %s but does not serve %s, which that seat's protocol promises",
 					module, c.Name, strings.Join(missing, ", ")))
@@ -221,10 +221,10 @@ func CatalogueProblems(shelf Shelf) []string {
 
 // unserved is what a seat's protocol promises and the claimant does not answer. Only the tools
 // are checked: `accepts` and `emits` are wired by the runtime from the declaration, while a tool
-// is code the module either has or has not written.
+// is code the module either has or has not written — under the claim's serves, or among its own.
-func unserved(m Manifest, s SeatDeclaration) []string {
+func unserved(m Manifest, c Claim, s SeatDeclaration) []string {
 	has := map[string]bool{}
-	for _, t := range m.Tools {
+	for _, t := range c.ServesFor(m) {
 		has[t] = true
 	}
 	var missing []string

internal/catalogue/seats_declared_test.go

@@ -70,6 +70,22 @@ func TestAHolderMustServeWhatItsSeatPromises(t *testing.T) {
 	}
 }
 
+// The claim may say what it serves for the role instead, when the module's own tools are not the
+// seat's verbs (ADR 0160).
+func TestAClaimMayNameWhatItServesForTheSeat(t *testing.T) {
+	m := telegram()
+	m.Tools = []string{"telegram_send"}
+	m.Claims = append([]Claim(nil), m.Claims...)
+	for i := range m.Claims {
+		if m.Claims[i].Name == "telegram-sender" {
+			m.Claims[i].Serves = []string{"status"}
+		}
+	}
+	if got := problemsFor(t, Shelf{"telegram": m}); strings.Contains(got, "does not serve") {
+		t.Fatalf("a claim naming the seat's verb was refused: %s", got)
+	}
+}
+
 // A seat with no protocol is a marker: which module is this node's showcase, or its packet filter.
 // Most node-scoped seats are markers, so refusing one would refuse the majority of the set.
 func TestASeatWithoutAProtocolIsAMarkerNotAMistake(t *testing.T) {

internal/catalogue/seats_test.go

@@ -44,7 +44,7 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 			delivered[s.Delivers] = s.Name
 		}
 	}
-	if len(Seats()) != 14 {
+	if len(Seats()) != 15 {
 		t.Errorf("the mesh defines %d seats rather than 14; the set is closed, so a change here is "+
 			"a decision (novox/hq ADR 0110): %s", len(Seats()), seatNames())
 	}
@@ -249,7 +249,7 @@ func TestAPinStillWinsOverTheSeat(t *testing.T) {
 	// A consumer coupled to one provider's contents has said so, and the seat does not overrule it.
 	got, err := Resolve(registryShelf(), []string{"builder"}, reachable(),
 		World{Offered: twoRegistries(), Held: giteaHoldsTheSeat(),
-			Pinned: map[string]string{"npm-package-registry": "archive"}})
+			Pinned: map[string]Chosen{"npm-package-registry": {Node: "archive", Module: "verdaccio"}}})
 	if err != nil {
 		t.Fatal(err)
 	}

internal/catalogue/vault_seat_test.go

@@ -0,0 +1,25 @@
+package catalogue
+
+import "testing"
+
+// The vault's provision is one the controller itself dereferences — every minted credential is
+// sealed with it — so it is delivered by a seat of the mesh's own, and a second provider is a second
+// claimant refused by name rather than a candidate for a pin (novox/hq ADR 0161, issue 106).
+func TestTheVaultsSeatDeliversSecret(t *testing.T) {
+	seat, known := SeatNamed("mesh-vault")
+	if !known {
+		t.Fatal("mesh-vault is not in the mesh's own set")
+	}
+	if seat.Scope != ScopeMesh || seat.Delivers != "secret" {
+		t.Fatalf("mesh-vault is %s-scoped and delivers %q; one per mesh, delivering secret", seat.Scope, seat.Delivers)
+	}
+	vault := Manifest{Module: "mesh-vault", Provides: []Offer{{Name: "secret", Scope: ScopeMesh}},
+		Claims: []Claim{{Name: "mesh-vault", Scope: ScopeMesh}}}
+	if err := CanHold(vault, seat); err != nil {
+		t.Fatalf("the vault, claiming its seat and providing secret, was refused: %v", err)
+	}
+	another := Manifest{Module: "other-vault", Provides: []Offer{{Name: "secret", Scope: ScopeMesh}}}
+	if err := CanHold(another, seat); err == nil {
+		t.Fatal("a provider of secret that does not claim the seat was allowed to hold it")
+	}
+}

internal/catalogue/verbs.go

@@ -91,12 +91,31 @@ var ControllerVerbs = []Verb{
 			"module": "one module's name; every module when absent",
 			"log":    "a build's id (as `builds` lists it): print what the build machine said, line by line",
 		}, nil)},
+	{Name: "plans", Description: "What the last merges produced and where each stands (novox/hq ADR 0162): " +
+		"the tiers, the tier a plan is at, what it waits for and since when; one plan whole, given its id.",
+		Input: schema(map[string]string{
+			"id":         "a plan's id (as `plans` lists them): that plan, tier by tier",
+			"stop":       "a plan's id: stop it — what was asked still builds, nothing further is asked",
+			"repository": "owner/repository: the plan a merge there would produce, saving nothing (what-if); with paths or modules",
+			"paths":      "with repository: the files the merge would change, comma-separated, from the repository's root",
+			"modules":    "with repository: or the modules it would change, comma-separated",
+		}, nil)},
 	{Name: "plan", Description: "What one machine would run, and why: the declaration the mesh would send it.",
 		Input: schema(map[string]string{"node": "the machine's name"}, []string{"node"})},
 	{Name: "assign", Description: "Put a module on a machine. Refused with the mesh's own words when it cannot resolve there.",
 		Input: schema(map[string]string{"node": "the machine's name", "module": "the module's name"}, []string{"node", "module"})},
 	{Name: "unassign", Description: "Take a module off a machine.",
 		Input: schema(map[string]string{"node": "the machine's name", "module": "the module's name"}, []string{"node", "module"})},
+	{Name: "pin", Description: "Tell a machine which provider answers a provision for it — the module, and the node " +
+		"it runs on, both. Asked for when more than one could answer; the refusal lists them.",
+		Input: schema(map[string]string{
+			"node":      "the machine's name",
+			"provision": "the provision, as the consumer requires it",
+			"from":      "the node the chosen provider runs on",
+			"module":    "the module providing it there",
+		}, []string{"node", "provision", "from", "module"})},
+	{Name: "unpin", Description: "Take that choice back, putting the question to the mesh again.",
+		Input: schema(map[string]string{"node": "the machine's name", "provision": "the provision"}, []string{"node", "provision"})},
 	{Name: "push", Description: "Send a machine everything it should be — or every machine that is behind, when no machine is named.",
 		Input: schema(map[string]string{"node": "the machine's name; every machine behind when absent"}, nil)},
 	{Name: "rotate", Description: "Replace a credential. A pair credential, by provision (and a consuming machine, " +
@@ -133,7 +152,22 @@ func schema(properties map[string]string, required []string) map[string]any {
 	return out
 }
 
-// unservedVerbs is what a seat promises and a claimant's `tools` does not answer.
+// unpromised is what a claim says it serves and the seat's protocol never promised.
+func unpromised(serves []string, promised []Verb) []string {
+	has := map[string]bool{}
+	for _, v := range promised {
+		has[v.Name] = true
+	}
+	var extra []string
+	for _, s := range serves {
+		if !has[s] {
+			extra = append(extra, s)
+		}
+	}
+	return extra
+}
+
+// unservedVerbs is what a seat promises and a claimant's offer for it does not answer.
 func unservedVerbs(tools []string, promised []Verb) []string {
 	has := map[string]bool{}
 	for _, t := range tools {

internal/inventory/adoption.go

@@ -164,6 +164,18 @@ type Held struct {
 	Since   time.Time `json:"since"`
 	Changed string    `json:"changed,omitempty"`
 	Kept    string    `json:"kept,omitempty"`
+	// Facts is what a take compares (novox/hq ADR 0163), as the host reported it: for a found
+	// container its image and the image's date, the networks and their other members, mounts and
+	// ports, beside the declared image, ports and volumes, and whether the declared image is the
+	// older; for a found file whether the declared content differs and how.
+	Facts map[string]any `json:"facts,omitempty"`
+}
+
+// A Stray is a container a machine runs that the mesh neither wrote nor holds (ADR 0163).
+type Stray struct {
+	Kind   string `json:"kind"`
+	Name   string `json:"name"`
+	Detail string `json:"detail,omitempty"`
 }
 
 // Reach is one thing reachable on an adopted node: a listening socket or a published port.
@@ -181,6 +193,8 @@ type Adoption struct {
 	Held      []Held
 	Firewall  string
 	Reachable []Reach
+	// Strays is what the machine runs that nobody asked for, as last reported (ADR 0163).
+	Strays []Stray
 	// At is when it said so; zero when it never has.
 	At time.Time
 }
@@ -189,6 +203,16 @@ type Adoption struct {
 // question is the machine as it is now.
 func (i *Inventory) RecordAdoption(ctx context.Context, node string, held []Held, firewall string,
 	reachable []Reach) error {
+	return i.RecordAdoptionWithStrays(ctx, node, held, firewall, reachable, nil)
+}
+
+// RecordAdoptionWithStrays is RecordAdoption with what the machine says strays on it (ADR 0163).
+func (i *Inventory) RecordAdoptionWithStrays(ctx context.Context, node string, held []Held, firewall string,
+	reachable []Reach, strays []Stray) error {
+	straysRaw, err := json.Marshal(nonNil(strays))
+	if err != nil {
+		return err
+	}
 	heldRaw, err := json.Marshal(nonNil(held))
 	if err != nil {
 		return err
@@ -198,9 +222,9 @@ func (i *Inventory) RecordAdoption(ctx context.Context, node string, held []Held
 		return err
 	}
 	_, err = i.store.Pool().Exec(ctx,
-		`update node set held = $2, firewall = nullif($3, ''), reachable = $4,
+		`update node set held = $2, firewall = nullif($3, ''), reachable = $4, strays = $5,
 		        adoption_reported = now(), last_seen = now()
-		  where id = $1`, node, heldRaw, firewall, reachRaw)
+		  where id = $1`, node, heldRaw, firewall, reachRaw, straysRaw)
 	return err
 }
 
@@ -213,12 +237,12 @@ func nonNil[T any](s []T) []T {
 
 // AdoptionOf is what a node last reported about adoption.
 func (i *Inventory) AdoptionOf(ctx context.Context, name string) (Adoption, error) {
-	var heldRaw, reachRaw []byte
+	var heldRaw, reachRaw, straysRaw []byte
 	var firewall *string
 	var at *time.Time
 	err := i.store.Pool().QueryRow(ctx,
-		`select held, firewall, reachable, adoption_reported from node where name = $1`, name).
+		`select held, firewall, reachable, adoption_reported, strays from node where name = $1`, name).
-		Scan(&heldRaw, &firewall, &reachRaw, &at)
+		Scan(&heldRaw, &firewall, &reachRaw, &at, &straysRaw)
 	if errors.Is(err, pgx.ErrNoRows) {
 		return Adoption{}, fmt.Errorf("%w: %s", ErrNoSuchNode, name)
 	}
@@ -237,6 +261,11 @@ func (i *Inventory) AdoptionOf(ctx context.Context, name string) (Adoption, erro
 			return Adoption{}, err
 		}
 	}
+	if len(straysRaw) > 0 {
+		if err := json.Unmarshal(straysRaw, &out.Strays); err != nil {
+			return Adoption{}, err
+		}
+	}
 	if len(reachRaw) > 0 {
 		if err := json.Unmarshal(reachRaw, &out.Reachable); err != nil {
 			return Adoption{}, err

internal/inventory/busrecords.go

@@ -49,7 +49,8 @@ func (i *Inventory) BusRecords(ctx context.Context) (broker.Records, error) {
 		}
 	}
 
-	out := broker.Records{Assigned: map[string][]broker.Declared{}, People: map[string][]string{}}
+	out := broker.Records{Assigned: map[string][]broker.Declared{}, People: map[string][]string{},
+		Interchangeable: map[string]bool{}}
 	for _, n := range nodes {
 		out.Nodes = append(out.Nodes, n.Name)
 		modules, err := i.Assigned(ctx, n.Name)
@@ -72,6 +73,9 @@ func (i *Inventory) BusRecords(ctx context.Context) (broker.Records, error) {
 						"be derived", module, n.Name)
 			}
 			out.Assigned[n.Name] = append(out.Assigned[n.Name], declaredFor(m, seats))
+			if m.Instances == catalogue.InstancesInterchangeable {
+				out.Interchangeable[m.Module] = true
+			}
 		}
 	}
 

internal/inventory/catalogue.go

@@ -841,24 +841,28 @@ func (i *Inventory) SettingsFor(ctx context.Context, nodeName, module string) ([
 	return layers, rows.Err()
 }
 
-// PinProvision records which node a machine gets a provision from.
+// PinProvision records which provider a machine gets a provision from: a module, and the node it
+// runs on — both, always (novox/hq #258). A provision comes from a module, and the same module on
+// two machines is two answers, so neither half alone says which.
 //
-// Only needed when more than one node could answer. Recordable before that, because a mesh with
+// Only needed when more than one could answer. Recordable before that, because a mesh with one
-// one database should not change where an existing machine gets its data the day a second
+// database should not change where an existing machine gets its data the day a second arrives.
-// arrives.
+func (i *Inventory) PinProvision(ctx context.Context, nodeName, provision, providerNode, module string) error {
-func (i *Inventory) PinProvision(ctx context.Context, nodeName, provision, provider string) error {
+	if strings.TrimSpace(module) == "" {
+		return fmt.Errorf("a pin names the module providing %q as well as the node it runs on", provision)
+	}
 	node, err := i.NodeByName(ctx, nodeName)
 	if err != nil {
 		return err
 	}
-	from, err := i.NodeByName(ctx, provider)
+	from, err := i.NodeByName(ctx, providerNode)
 	if err != nil {
 		return err
 	}
 	_, err = i.store.Pool().Exec(ctx,
-		`insert into provision_pin (node, name, provider) values ($1, $2, $3)
+		`insert into provision_pin (node, name, provider, module) values ($1, $2, $3, $4)
-		 on conflict (node, name) do update set provider = excluded.provider, pinned_at = now()`,
+		 on conflict (node, name) do update set provider = excluded.provider, module = excluded.module, pinned_at = now()`,
-		node.ID, provision, from.ID)
+		node.ID, provision, from.ID, module)
 	return err
 }
 
@@ -879,27 +883,28 @@ func (i *Inventory) UnpinProvision(ctx context.Context, nodeName, provision stri
 	return nil
 }
 
-// PinsFor is what a node was told about where its provisions come from.
+// PinsFor is what a node was told about where its provisions come from. A record from before a pin
-func (i *Inventory) PinsFor(ctx context.Context, nodeName string) (map[string]string, error) {
+// named the module carries the node alone; the resolver honours it while it is unambiguous.
+func (i *Inventory) PinsFor(ctx context.Context, nodeName string) (map[string]catalogue.Chosen, error) {
 	node, err := i.NodeByName(ctx, nodeName)
 	if err != nil {
 		return nil, err
 	}
 	rows, err := i.store.Pool().Query(ctx,
-		`select p.name, n.name from provision_pin p join node n on n.id = p.provider
+		`select p.name, n.name, coalesce(p.module, '') from provision_pin p join node n on n.id = p.provider
 		 where p.node = $1`, node.ID)
 	if err != nil {
 		return nil, err
 	}
 	defer rows.Close()
 
-	out := map[string]string{}
+	out := map[string]catalogue.Chosen{}
 	for rows.Next() {
-		var name, provider string
+		var name, provider, module string
-		if err := rows.Scan(&name, &provider); err != nil {
+		if err := rows.Scan(&name, &provider, &module); err != nil {
 			return nil, err
 		}
-		out[name] = provider
+		out[name] = catalogue.Chosen{Node: provider, Module: module}
 	}
 	return out, rows.Err()
 }

internal/inventory/catalogue_test.go

@@ -385,19 +385,19 @@ func TestAPinSurvivesAndCanBeChanged(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
-	if err := inv.PinProvision(ctx, "user", "postgres-database", "first"); err != nil {
+	if err := inv.PinProvision(ctx, "user", "postgres-database", "first", "postgres"); err != nil {
 		t.Fatal(err)
 	}
 	// Changing the answer replaces it rather than adding a second, or a machine would be told to
 	// use two databases and nothing would say which.
-	if err := inv.PinProvision(ctx, "user", "postgres-database", "second"); err != nil {
+	if err := inv.PinProvision(ctx, "user", "postgres-database", "second", "postgres"); err != nil {
 		t.Fatal(err)
 	}
 	pins, err := inv.PinsFor(ctx, "user")
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(pins) != 1 || pins["postgres-database"] != "second" {
+	if len(pins) != 1 || pins["postgres-database"].Node != "second" || pins["postgres-database"].Module != "postgres" {
 		t.Fatalf("got %v", pins)
 	}
 	if err := inv.UnpinProvision(ctx, "user", "postgres-database"); err != nil {
@@ -422,7 +422,7 @@ func TestAPinGoesWhenTheProviderLeavesTheMesh(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
-	if err := inv.PinProvision(ctx, "consumer", "postgres-database", "provider"); err != nil {
+	if err := inv.PinProvision(ctx, "consumer", "postgres-database", "provider", "postgres"); err != nil {
 		t.Fatal(err)
 	}
 	if _, err := inv.store.Pool().Exec(ctx, `delete from node where name = 'provider'`); err != nil {

internal/inventory/dependencies.go

@@ -0,0 +1,124 @@
+package inventory
+
+import (
+	"context"
+	"sort"
+	"strings"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// The kinds of edge in the catalogue's one dependency relation (novox/hq ADR 0162).
+const (
+	// EdgeStandsOn: the module's artifact is built on the other's.
+	EdgeStandsOn = "stands-on"
+	// EdgePackages: the module's build reads the other's repository.
+	EdgePackages = "packages"
+	// EdgeBuiltBy: the module is built by the holder of the build-machine seat.
+	EdgeBuiltBy = "built-by"
+	// EdgeDeclared: the manifest's own `build.on`.
+	EdgeDeclared = "declared"
+)
+
+// Edge is one dependency: From depends on To, in the way Kind says.
+type Edge struct {
+	From string `json:"from"`
+	To   string `json:"to"`
+	Kind string `json:"kind"`
+}
+
+// Dependencies is the catalogue's dependency relation, whole: every module the mesh holds, with
+// an edge to each module it depends on and the kind of dependency on the edge. One answer, so
+// nothing else computes an edge (novox/hq ADR 0162) — the merge handler, `build --on` and the
+// overview all read this.
+//
+// Four sources, one relation: a manifest's `build.on`; the artifacts the latest build was made
+// against (an `artifact-store://<module>/…` reference is an edge to that module); the repositories
+// the latest build read (an edge to the module whose source that is); and the build machine, which
+// every source-built module is built by.
+func (i *Inventory) Dependencies(ctx context.Context) ([]Edge, error) {
+	entries, err := i.Catalogued(ctx)
+	if err != nil {
+		return nil, err
+	}
+	against, err := i.BuiltAgainst(ctx)
+	if err != nil {
+		return nil, err
+	}
+	read, err := i.ReadRepositories(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return dependenciesOf(entries, against, read), nil
+}
+
+// dependenciesOf is Dependencies over what was read, so a test can hand it a catalogue.
+func dependenciesOf(entries []Entry, against map[string][]string, read map[string][]ReadRepository) []Edge {
+	known := map[string]bool{}
+	byRepository := map[string][]string{}
+	var builders []string
+	for _, e := range entries {
+		name := e.Manifest.Module
+		known[name] = true
+		if r := repositoryKey(e.Source.Repository); r != "" {
+			byRepository[r] = append(byRepository[r], name)
+		}
+		if e.Manifest.ClaimsSeat("mesh-build-machine") {
+			builders = append(builders, name)
+		}
+	}
+	seen := map[Edge]bool{}
+	var out []Edge
+	add := func(from, to, kind string) {
+		if from == to || !known[to] {
+			return
+		}
+		e := Edge{From: from, To: to, Kind: kind}
+		if !seen[e] {
+			seen[e] = true
+			out = append(out, e)
+		}
+	}
+	for _, e := range entries {
+		name := e.Manifest.Module
+		if e.Manifest.Build != nil {
+			for _, on := range e.Manifest.Build.On {
+				if on.Module != "" {
+					add(name, on.Module, EdgeDeclared)
+				}
+			}
+		}
+		for _, ref := range against[name] {
+			if rest, ok := strings.CutPrefix(ref, catalogue.ArtifactStoreScheme); ok {
+				if base, _, found := strings.Cut(rest, "/"); found {
+					add(name, base, EdgeStandsOn)
+				}
+			}
+		}
+		for _, r := range read[name] {
+			for _, other := range byRepository[repositoryKey(r.Repository)] {
+				add(name, other, EdgePackages)
+			}
+		}
+		if e.Source.Repository != "" {
+			for _, b := range builders {
+				add(name, b, EdgeBuiltBy)
+			}
+		}
+	}
+	sort.Slice(out, func(a, b int) bool {
+		if out[a].From != out[b].From {
+			return out[a].From < out[b].From
+		}
+		if out[a].To != out[b].To {
+			return out[a].To < out[b].To
+		}
+		return out[a].Kind < out[b].Kind
+	})
+	return out
+}
+
+// repositoryKey is a repository as compared: lower-cased, without a trailing `.git`.
+func repositoryKey(repository string) string {
+	return strings.ToLower(strings.TrimSuffix(strings.TrimSpace(repository), ".git"))
+}

internal/inventory/dependencies_test.go

@@ -0,0 +1,64 @@
+package inventory
+
+import (
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// The catalogue's one dependency relation (novox/hq ADR 0162): four kinds of edge from one call.
+func TestDependenciesAreOneRelationWithTheirKinds(t *testing.T) {
+	entry := func(name, repository string) Entry {
+		return Entry{Manifest: catalogue.Manifest{Module: name}, Source: Source{Repository: repository}}
+	}
+	builder := entry("builder", "http://forge/novox/mesh-catalog.git")
+	builder.Manifest.Claims = []catalogue.Claim{{Name: "mesh-build-machine", Scope: catalogue.ScopeMesh}}
+	plugin := entry("shop-plugin", "http://forge/novox/mesh-catalog.git")
+	plugin.Manifest.Build = &catalogue.Build{On: []catalogue.BuildsOn{{Arg: "BASE", Module: "shop"}}}
+	entries := []Entry{
+		entry("mesh-tools", "http://forge/novox/mesh-tools.git"),
+		entry("shop", "http://forge/novox/mesh-catalog.git"),
+		plugin,
+		builder,
+		entry("mesh-controller", "http://forge/novox/mesh-controller.git"),
+		entry("route-proxy", "http://forge/novox/mesh-catalog.git"),
+		{Manifest: catalogue.Manifest{Module: "hand-made"}},
+	}
+	against := map[string][]string{
+		"shop":    {catalogue.ArtifactStoreScheme + "mesh-tools/runtime@sha256:a"},
+		"builder": {catalogue.ArtifactStoreScheme + "mesh-tools/runtime@sha256:a"},
+	}
+	read := map[string][]ReadRepository{
+		"route-proxy": {{Repository: "http://forge/novox/mesh-controller.git", Ref: "main"}},
+	}
+	got := dependenciesOf(entries, against, read)
+	has := func(from, to, kind string) bool {
+		for _, e := range got {
+			if e == (Edge{From: from, To: to, Kind: kind}) {
+				return true
+			}
+		}
+		return false
+	}
+	for _, want := range []Edge{
+		{"shop", "mesh-tools", EdgeStandsOn},
+		{"builder", "mesh-tools", EdgeStandsOn},
+		{"shop-plugin", "shop", EdgeDeclared},
+		{"route-proxy", "mesh-controller", EdgePackages},
+		{"shop", "builder", EdgeBuiltBy},
+		{"mesh-controller", "builder", EdgeBuiltBy},
+		{"mesh-tools", "builder", EdgeBuiltBy},
+	} {
+		if !has(want.From, want.To, want.Kind) {
+			t.Errorf("missing %+v in %+v", want, got)
+		}
+	}
+	if has("builder", "builder", EdgeBuiltBy) {
+		t.Error("the builder is not built by itself")
+	}
+	for _, e := range got {
+		if e.From == "hand-made" {
+			t.Errorf("a module with no source depends on nothing: %+v", e)
+		}
+	}
+}

internal/inventory/migrations/0050-a-pin-names-the-module.sql

@@ -0,0 +1,12 @@
+-- A pin names the module as well as the node (novox/hq #258).
+--
+-- 0008 said "not a module: the same module on two machines is two answers, and which machine is the
+-- whole question". Half right. Two modules on one machine can both answer a provision — public-acme
+-- and step-ca both offer acme-ca on novox — and then which *module* is the whole question, and a
+-- node alone cannot ask it. The resolver, given a node that answered twice, took the last one listed.
+--
+-- A provider is a (node, module) pair (design 23), and a pin names the pair. Nullable, so a record
+-- made before this was asked keeps meaning what it meant: honoured while that node answers once,
+-- refused with the module asked for when it answers twice.
+alter table provision_pin add column module text;
+

internal/inventory/migrations/0051-a-pin-made-before-is-completed.sql

@@ -0,0 +1,19 @@
+-- The records already made are completed where the mesh can tell: a pin naming a node on which
+-- exactly one assigned module offers the provision (or is the module itself, for a requirement that
+-- names a module) gets that module. A node that answers twice is left to say which — the resolver
+-- refuses it with the module asked for, rather than this guessing on its behalf.
+update provision_pin p
+   set module = sub.module
+  from (
+        select p2.node, p2.name, min(a.module) as module, count(distinct a.module) as answers
+          from provision_pin p2
+          join assignment a on a.node = p2.provider
+          join module m on m.name = a.module
+         where p2.module is null
+           and (a.module = p2.name
+                or exists (select 1
+                             from jsonb_array_elements(coalesce(m.manifest -> 'provides', '[]'::jsonb)) e
+                            where (case when jsonb_typeof(e) = 'string' then e #>> '{}' else e ->> 'name' end) = p2.name))
+         group by p2.node, p2.name
+       ) sub
+ where sub.node = p.node and sub.name = p.name and sub.answers = 1;

internal/inventory/migrations/0052-a-merge-is-a-plan-the-mesh-keeps.sql

@@ -0,0 +1,19 @@
+-- A merge produces a tiered plan the mesh keeps (novox/hq ADR 0162): what the merge changed and
+-- everything standing on it, sorted into tiers, each module's state, and the tier the plan is at.
+-- Kept so a controller replaced mid-plan resumes it, and so `status` can say what a merge still
+-- waits for.
+create table release_plan (
+    id          text        primary key,
+    repository  text        not null,
+    commit_hash text        not null,
+    created     timestamptz not null default now(),
+    updated     timestamptz not null default now(),
+    -- building: a tier's builds are asked; rolling: the tier is built and the machines are applying
+    -- what a later tier needs running; done; failed.
+    state       text        not null,
+    tier        int         not null default 0,
+    tiers       jsonb       not null,
+    modules     jsonb       not null,
+    note        text        not null default ''
+);
+create index release_plan_open on release_plan (created) where state in ('building', 'rolling');

internal/inventory/migrations/0053-a-machine-says-what-strays-on-it.sql

@@ -0,0 +1,3 @@
+-- What runs on a machine that the mesh neither wrote nor holds, as the host reports it with every
+-- apply (novox/hq ADR 0163): a container left behind by a cutover is seen the day it is left.
+alter table node add column strays jsonb;

internal/inventory/people_test.go

@@ -42,8 +42,11 @@ func TestAPersonMayCallToolsAndNothingElse(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if len(perms.Publish) != 1 || perms.Publish[0] != "mesh.mod.mesh-catalog.tool.catalog_tools" {
+		// The one tool, both ways it is addressed (novox/hq ADR 0159): to whichever instance
-			t.Errorf("ada may publish %v, which should be the one tool and nothing else", perms.Publish)
+		// answers, and to the instance on one machine. Nothing else.
+		if len(perms.Publish) != 2 || perms.Publish[0] != "mesh.mod.mesh-catalog.tool.catalog_tools" ||
+			perms.Publish[1] != "mesh.mod.mesh-catalog.tool.catalog_tools.*" {
+			t.Errorf("ada may publish %v, which should be the one tool, both ways addressed, and nothing else", perms.Publish)
 		}
 		for _, s := range perms.Publish {
 			if strings.HasPrefix(s, "mesh.control") || strings.HasPrefix(s, "mesh.node") ||

internal/inventory/pin_completed_test.go

@@ -0,0 +1,86 @@
+package inventory
+
+import (
+	"context"
+	"os"
+	"testing"
+)
+
+// A pin made before it named the module (migration 0051, novox/hq #258): completed where the node it
+// names answers once, left for a person where it answers twice.
+
+func legacyPin(t *testing.T, inv *Inventory, node, provision, provider string) {
+	t.Helper()
+	_, err := inv.store.Pool().Exec(context.Background(),
+		`insert into provision_pin (node, name, provider)
+		 select u.id, $2, p.id from node u, node p where u.name = $1 and p.name = $3`,
+		node, provision, provider)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func completeEarlierPins(t *testing.T, inv *Inventory) {
+	t.Helper()
+	sql, err := os.ReadFile("migrations/0051-a-pin-made-before-is-completed.sql")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := inv.store.Pool().Exec(context.Background(), string(sql)); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestAPinMadeBeforeIsCompletedWhenTheNodeAnswersOnce(t *testing.T) {
+	inv := fresh(t)
+	ctx := context.Background()
+	for _, n := range []string{"user", "provider"} {
+		if _, err := inv.AddNode(ctx, n); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, m := range []string{"postgres", "redis"} {
+		if err := inv.RegisterModule(ctx, manifest(m, []string{m + "-database"}, nil), Source{}); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := inv.Assign(ctx, "provider", m); err != nil {
+			t.Fatal(err)
+		}
+	}
+	legacyPin(t, inv, "user", "postgres-database", "provider")
+	completeEarlierPins(t, inv)
+	pins, err := inv.PinsFor(ctx, "user")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := pins["postgres-database"]; got.Node != "provider" || got.Module != "postgres" {
+		t.Fatalf("the record was not completed with the one module that answers: %+v", got)
+	}
+}
+
+func TestAPinMadeBeforeIsLeftOpenWhenTheNodeAnswersTwice(t *testing.T) {
+	inv := fresh(t)
+	ctx := context.Background()
+	for _, n := range []string{"user", "provider"} {
+		if _, err := inv.AddNode(ctx, n); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, m := range []string{"public-acme", "step-ca"} {
+		if err := inv.RegisterModule(ctx, manifest(m, []string{"acme-ca"}, nil), Source{}); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := inv.Assign(ctx, "provider", m); err != nil {
+			t.Fatal(err)
+		}
+	}
+	legacyPin(t, inv, "user", "acme-ca", "provider")
+	completeEarlierPins(t, inv)
+	pins, err := inv.PinsFor(ctx, "user")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := pins["acme-ca"]; got.Node != "provider" || got.Module != "" {
+		t.Fatalf("a node that answers twice was guessed for: %+v", got)
+	}
+}

internal/inventory/plans.go

@@ -0,0 +1,127 @@
+package inventory
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// A Plan is what a merge produces (novox/hq ADR 0162): the modules it changed and everything
+// standing on them, sorted into tiers, each module's state, and the tier the plan is at. Kept in
+// the store so a controller replaced mid-plan resumes it, and so `status` can say what a merge
+// still waits for.
+type Plan struct {
+	ID         string                 `json:"id"`
+	Repository string                 `json:"repository"`
+	Commit     string                 `json:"commit"`
+	Created    time.Time              `json:"created"`
+	Updated    time.Time              `json:"updated"`
+	State      string                 `json:"state"`
+	Tier       int                    `json:"tier"`
+	Tiers      [][]string             `json:"tiers"`
+	Modules    map[string]*PlanModule `json:"modules"`
+	Note       string                 `json:"note,omitempty"`
+}
+
+// PlanModule is one module's state within a plan.
+type PlanModule struct {
+	// State: asked, built, failed; empty for a module whose tier has not been asked yet.
+	State   string     `json:"state,omitempty"`
+	AskedAt *time.Time `json:"asked_at,omitempty"`
+	BuiltAt *time.Time `json:"built_at,omitempty"`
+	// SentAt is when the plan sent the machines running this module its new build, because a
+	// later tier is built by it (ADR 0163's gate): the reports that open the gate are the ones
+	// after this.
+	SentAt *time.Time `json:"sent_at,omitempty"`
+	Commit string     `json:"commit,omitempty"`
+	Why    string     `json:"why,omitempty"`
+}
+
+// The states a plan passes through.
+const (
+	PlanBuilding = "building"
+	PlanRolling  = "rolling"
+	PlanDone     = "done"
+	PlanFailed   = "failed"
+)
+
+// Open says whether the plan is still being worked.
+func (p Plan) Open() bool { return p.State == PlanBuilding || p.State == PlanRolling }
+
+// SavePlan writes a plan, new or changed, whole: the plan is small and read as one thing.
+func (i *Inventory) SavePlan(ctx context.Context, p Plan) error {
+	tiers, err := json.Marshal(p.Tiers)
+	if err != nil {
+		return err
+	}
+	modules, err := json.Marshal(p.Modules)
+	if err != nil {
+		return err
+	}
+	_, err = i.store.Pool().Exec(ctx,
+		`insert into release_plan (id, repository, commit_hash, created, updated, state, tier, tiers, modules, note)
+		 values ($1, $2, $3, $4, now(), $5, $6, $7, $8, $9)
+		 on conflict (id) do update set updated = now(), state = excluded.state, tier = excluded.tier,
+		        tiers = excluded.tiers, modules = excluded.modules, note = excluded.note`,
+		p.ID, p.Repository, p.Commit, p.Created, p.State, p.Tier, tiers, modules, p.Note)
+	return err
+}
+
+// OpenPlans is every plan still being worked, oldest first.
+func (i *Inventory) OpenPlans(ctx context.Context) ([]Plan, error) {
+	return i.plans(ctx, `where state in ('building', 'rolling') order by created`)
+}
+
+// RecentPlans is the last few plans, newest first, open or not — what the overview shows.
+func (i *Inventory) RecentPlans(ctx context.Context, limit int) ([]Plan, error) {
+	return i.plans(ctx, fmt.Sprintf(`order by created desc limit %d`, limit))
+}
+
+// PlanByID is one plan.
+func (i *Inventory) PlanByID(ctx context.Context, id string) (Plan, error) {
+	plans, err := i.plans(ctx, `where id = '`+id+`'`)
+	if err != nil {
+		return Plan{}, err
+	}
+	if len(plans) == 0 {
+		return Plan{}, fmt.Errorf("no plan %s", id)
+	}
+	return plans[0], nil
+}
+
+func (i *Inventory) plans(ctx context.Context, tail string) ([]Plan, error) {
+	rows, err := i.store.Pool().Query(ctx,
+		`select id, repository, commit_hash, created, updated, state, tier, tiers, modules, note
+		   from release_plan `+tail)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var out []Plan
+	for rows.Next() {
+		var p Plan
+		var tiers, modules []byte
+		if err := rows.Scan(&p.ID, &p.Repository, &p.Commit, &p.Created, &p.Updated, &p.State,
+			&p.Tier, &tiers, &modules, &p.Note); err != nil {
+			return nil, err
+		}
+		if err := json.Unmarshal(tiers, &p.Tiers); err != nil {
+			return nil, err
+		}
+		if err := json.Unmarshal(modules, &p.Modules); err != nil {
+			return nil, err
+		}
+		if p.Modules == nil {
+			p.Modules = map[string]*PlanModule{}
+		}
+		out = append(out, p)
+	}
+	if errors.Is(rows.Err(), pgx.ErrNoRows) {
+		return nil, nil
+	}
+	return out, rows.Err()
+}

internal/inventory/plans_test.go

@@ -0,0 +1,48 @@
+package inventory
+
+import (
+	"testing"
+	"time"
+)
+
+// A plan is a record the mesh keeps and resumes (novox/hq ADR 0162): written whole, read back open,
+// advanced, and gone from the open ones when done.
+func TestAPlanIsKeptAdvancedAndResumedFromTheStore(t *testing.T) {
+	inv := ForTest(t)
+	ctx := t.Context()
+	p := Plan{ID: "plan-1", Repository: "novox/mesh-tools", Commit: "abc", Created: time.Now().UTC(),
+		State: PlanBuilding, Tiers: [][]string{{"mesh-tools"}, {"builder"}, {"shop"}},
+		Modules: map[string]*PlanModule{"mesh-tools": {}, "builder": {}, "shop": {}}}
+	if err := inv.SavePlan(ctx, p); err != nil {
+		t.Fatal(err)
+	}
+	open, err := inv.OpenPlans(ctx)
+	if err != nil || len(open) != 1 || open[0].ID != "plan-1" || len(open[0].Tiers) != 3 {
+		t.Fatalf("the plan was not kept whole: %v %+v", err, open)
+	}
+	// Another controller picks it up where it was left: a tier advanced and a module built.
+	now := time.Now().UTC()
+	resumed := open[0]
+	resumed.Tier = 1
+	resumed.Modules["mesh-tools"].State = "built"
+	resumed.Modules["mesh-tools"].BuiltAt = &now
+	resumed.State = PlanRolling
+	resumed.Note = "tier 0 built; waiting for builder on anchor to be applied"
+	if err := inv.SavePlan(ctx, resumed); err != nil {
+		t.Fatal(err)
+	}
+	again, err := inv.PlanByID(ctx, "plan-1")
+	if err != nil || again.Tier != 1 || again.Modules["mesh-tools"].State != "built" || again.State != PlanRolling {
+		t.Fatalf("the advanced plan did not come back as left: %v %+v", err, again)
+	}
+	again.State = PlanDone
+	if err := inv.SavePlan(ctx, again); err != nil {
+		t.Fatal(err)
+	}
+	if open, _ = inv.OpenPlans(ctx); len(open) != 0 {
+		t.Fatalf("a done plan is not open: %+v", open)
+	}
+	if recent, _ := inv.RecentPlans(ctx, 5); len(recent) != 1 || recent[0].State != PlanDone {
+		t.Fatalf("a done plan is still among the recent ones: %+v", recent)
+	}
+}

internal/inventory/secrets.go

@@ -398,7 +398,7 @@ func (i *Inventory) AcceptSecretForModule(ctx context.Context, node, module, nam
 		return err
 	}
 	if _, own := m.OwnSecrets[name]; !own {
-		return fmt.Errorf("%s does not declare %q as an own secret; %s", module, name, declaresOwn(m))
+		return fmt.Errorf("%s does not declare %q as an own secret; %s — a secret it requires from a provider is accepted with `--provider <node> [--local <name>]`, the value the running service already uses (novox/hq ADR 0163)", module, name, declaresOwn(m))
 	}
 	key, err := i.SealingKeyOf(ctx, node)
 	if err != nil {
@@ -546,7 +546,7 @@ func (i *Inventory) RotateModuleSecret(ctx context.Context, node, module, name s
 	}
 	own, declared := m.OwnSecrets[name]
 	if !declared {
-		return fmt.Errorf("%s does not declare %q as an own secret; %s", module, name, declaresOwn(m))
+		return fmt.Errorf("%s does not declare %q as an own secret; %s — a secret it requires from a provider is accepted with `--provider <node> [--local <name>]`, the value the running service already uses (novox/hq ADR 0163)", module, name, declaresOwn(m))
 	}
 	switch own.Taken {
 	case catalogue.TakenAtStart:

internal/link/builds_nats.go

@@ -173,7 +173,13 @@ func (m *natsMachine) Take(ctx context.Context, do func(context.Context, Build))
 				_ = msg.Term()
 				continue
 			}
+			// A build outlives the acknowledgement window many times over; said while it runs,
+			// as the controller says it for its own long handlers, so the server neither hands
+			// the ask to a second machine nor counts the wait against its deliveries.
+			working := make(chan struct{})
+			go stillWorking(msg, working)
 			do(ctx, &natsBuild{request: request, msg: msg, on: m.on, js: m.js})
+			close(working)
 		}
 	}
 }

internal/link/bus.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"github.com/novox/mesh-controller/internal/broker"
 	"time"
 
 	"github.com/nats-io/nats.go"
@@ -145,6 +146,24 @@ func (b OverNATS) PublishSeatEvent(ctx context.Context, seat, event string, body
 	return nil
 }
 
+// PublishMembership issues one assignment what it serves and reaches (novox/hq ADR 0160), last per
+// subject, so the runtime that connects later reads the current one and one that is running follows.
+// MembershipWait bounds how long issuing one membership may take. A publish the server refuses is
+// never acknowledged, and a stream publish waits for its acknowledgement for as long as its
+// context lives: on 2026-10-01 the daemon's own context was that long, and one refused membership
+// held the controller's receive loop for good (novox/hq issue 185).
+const MembershipWait = 10 * time.Second
+
+func (b OverNATS) PublishMembership(ctx context.Context, node, module string, body []byte) error {
+	ctx, cancel := context.WithTimeout(ctx, MembershipWait)
+	defer cancel()
+	_, err := b.JS.Publish(broker.MembershipSubject(node, module), body, nats.Context(ctx))
+	if err != nil {
+		return fmt.Errorf("issuing %s on %s its membership: %w", module, node, err)
+	}
+	return nil
+}
+
 func (b OverNATS) PublishDeclaration(ctx context.Context, node string, body []byte) error {
 	_, err := b.JS.Publish(DeclareSubject(node), body, nats.Context(ctx))
 	if err != nil {

internal/link/enrolment.go

@@ -286,18 +286,22 @@ func (e Enrolment) Heard(ctx context.Context, report Report) (news bool, err err
 	// schedule, when what it holds changes, not only after an apply — and never cleared by a
 	// report that carries none, which is every bare word that the node is there. An adopted node
 	// always names its firewall, so a report from one replaces all three, emptied held included.
-	if len(report.Held) > 0 || report.Firewall != "" || len(report.Reachable) > 0 {
+	if len(report.Held) > 0 || report.Firewall != "" || len(report.Reachable) > 0 || len(report.Strays) > 0 {
 		held := make([]inventory.Held, 0, len(report.Held))
 		for _, h := range report.Held {
 			held = append(held, inventory.Held{ID: h.ID, Module: h.Module, Kind: h.Kind,
-				Target: h.Target, Since: h.Since, Changed: h.Changed, Kept: h.Kept})
+				Target: h.Target, Since: h.Since, Changed: h.Changed, Kept: h.Kept, Facts: h.Facts})
+		}
+		strays := make([]inventory.Stray, 0, len(report.Strays))
+		for _, s := range report.Strays {
+			strays = append(strays, inventory.Stray{Kind: s.Kind, Name: s.Name, Detail: s.Detail})
 		}
 		reachable := make([]inventory.Reach, 0, len(report.Reachable))
 		for _, r := range report.Reachable {
 			reachable = append(reachable, inventory.Reach{Protocol: r.Protocol, Address: r.Address,
 				Port: r.Port, By: r.By, Published: r.Published, ContainerPort: r.ContainerPort})
 		}
-		if err := e.Inventory.RecordAdoption(ctx, node.ID, held, report.Firewall, reachable); err != nil {
+		if err := e.Inventory.RecordAdoptionWithStrays(ctx, node.ID, held, report.Firewall, reachable, strays); err != nil {
 			return false, err
 		}
 	}
@@ -320,6 +324,13 @@ func (e Enrolment) Heard(ctx context.Context, report Report) (news bool, err err
 			return false, err
 		}
 	}
+	if len(report.Profile) > 0 {
+		// The latest wins, as at enrolment: a capability the machine lost is one the plan must
+		// stop counting on (novox/hq ADR 0161).
+		if err := e.Inventory.RecordProfile(ctx, node.ID, report.Profile); err != nil {
+			return false, err
+		}
+	}
 	// What it says about the tunnel it carried (novox/hq ADR 0105), whenever it says it.
 	if report.Tunnel != nil {
 		if err := e.Inventory.RecordCarriedTunnel(ctx, node.ID, inventory.Carried{

internal/link/profile_report_test.go

@@ -0,0 +1,45 @@
+package link_test
+
+import (
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/link"
+)
+
+// A report may carry the machine's profile, detected again by the apply that reports, and the latest
+// replaces what enrolment recorded (novox/hq ADR 0161): a machine that switched its network manager
+// is a machine whose uplink holder lacks a capability at its next push, not at its next enrolment.
+func TestAReportsProfileReplacesTheEnrolledOne(t *testing.T) {
+	e, _, _ := anEnrolledHub(t)
+	ctx := t.Context()
+	first := map[string]any{"capabilities": []any{map[string]any{"name": "uplink-networkmanager", "present": true}}}
+	if _, err := e.Heard(ctx, link.Report{Node: "anchor", Profile: first}); err != nil {
+		t.Fatal(err)
+	}
+	got, err := e.Inventory.Profile(ctx, "anchor")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 1 || got[0].Name != "uplink-networkmanager" || !got[0].Present {
+		t.Fatalf("the report's profile was not kept: %+v", got)
+	}
+	// The machine switched managers; the next report says so and the old fact is gone.
+	second := map[string]any{"capabilities": []any{map[string]any{"name": "uplink-systemd-networkd", "present": true}}}
+	if _, err := e.Heard(ctx, link.Report{Node: "anchor", Profile: second}); err != nil {
+		t.Fatal(err)
+	}
+	got, err = e.Inventory.Profile(ctx, "anchor")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 1 || got[0].Name != "uplink-systemd-networkd" {
+		t.Fatalf("the latest profile did not replace the earlier one: %+v", got)
+	}
+	// A report with no profile leaves the last one standing.
+	if _, err := e.Heard(ctx, link.Report{Node: "anchor", Host: "1"}); err != nil {
+		t.Fatal(err)
+	}
+	if got, _ = e.Inventory.Profile(ctx, "anchor"); len(got) != 1 {
+		t.Fatalf("a report without a profile erased it: %+v", got)
+	}
+}

internal/link/protocol.go

@@ -193,6 +193,15 @@ type Report struct {
 	// refuses it whole — which is right, and makes every new field a flag day that the mesh could
 	// not see coming.
 	Host string `json:"host,omitempty"`
+
+	// Strays is what runs on the machine that the mesh neither wrote nor holds (ADR 0163).
+	Strays []Stray `json:"strays,omitempty"`
+
+	// Profile is what the machine can do, detected again by this apply (novox/hq ADR 0161): the
+	// same shape enrolment sends, so a machine that gained or lost a capability — switched its
+	// network manager — is known at its next push and not at its next enrolment. Absent from a host
+	// older than this, and then the enrolment's profile stands.
+	Profile map[string]any `json:"profile,omitempty"`
 	// Reachable is what can be reached on the machine now: every listening socket and every
 	// published container port. Only an adopted node reports it; it is what converging previews.
 	Reachable []Reach `json:"reachable,omitempty"`
@@ -264,6 +273,16 @@ type Held struct {
 	Changed string `json:"changed,omitempty"`
 	// Kept is where a file's original was kept.
 	Kept string `json:"kept,omitempty"`
+	// Facts is the found thing beside what the module declares — what a take compares (novox/hq
+	// ADR 0163): the host's own shape, carried as data and read by the preview.
+	Facts map[string]any `json:"facts,omitempty"`
+}
+
+// A Stray is a container a machine runs that the mesh neither wrote nor holds (ADR 0163).
+type Stray struct {
+	Kind   string `json:"kind"`
+	Name   string `json:"name"`
+	Detail string `json:"detail,omitempty"`
 }
 
 // Reach is one thing reachable on the machine: a listening socket, or a published container port.