Merge pull request 'The controller composes one tool runtime per node: its principal, the bundles, its process, and the gate (hq ADR 0175, to-be 38 WP2)' (#223) from feat/the-operators-machine into main

Another session took 0175 while that record was in review; the line printed on every converged
machine was pointing at an unrelated decision.

cmd/mesh-controller/adoption.go

@@ -95,7 +95,7 @@ func showFiltering(f inventory.Filtering, adopted bool) {
 		case fw.Active:
 			fmt.Printf("  found firewall    %s is ACTIVE on this converged machine; the next apply retires it again\n", fw.Kind)
 		case fw.RetiredBy == "removed":
-			fmt.Printf("  found firewall    %s, removed: the mesh's filter is what filters this machine (novox/hq ADR 0175)\n", fw.Kind)
+			fmt.Printf("  found firewall    %s, removed: the mesh's filter is what filters this machine (novox/hq ADR 0180)\n", fw.Kind)
 		case fw.RetiredBy == inventory.FilterMesh || fw.RetiredBy == "mesh":
 			fmt.Printf("  found firewall    %s, retired by the mesh; its configuration stays on disk\n", fw.Kind)
 		case fw.RetiredBy != "":

cmd/mesh-controller/build.go

@@ -522,6 +522,8 @@ func takeIn(ctx context.Context, inv *inventory.Inventory, result link.BuildResu
 	recorded := inventory.Source{
 		Repository: result.Repository, Path: result.Path, Ref: result.Ref,
 		BuiltFrom: result.Commit, Head: result.Commit,
+		// What it stood on, so registration can judge a built manifest's base (to-be 38 WP2.4).
+		Against: kept.Against,
 	}
 	if result.Source != nil && result.Source.Seat != "" {
 		recorded.Repository, recorded.Seat = result.Source.Repository, result.Source.Seat

cmd/mesh-controller/modules.go

@@ -557,7 +557,7 @@ func issueOnTheNewBus(ctx context.Context, inv *inventory.Inventory, m catalogue
 
 	user := broker.Principal{Kind: broker.KindModule, Node: node, Module: m.Module}.Username()
 	password, err := inv.MintBusPassword(ctx, inventory.BusUser{
-		Username: user, Kind: inventory.BusModule, Node: node, Module: m.Module,
+		Username: user, Kind: busKindOf(m.Module), Node: node, Module: m.Module,
 	})
 	if err != nil {
 		return err
@@ -577,6 +577,16 @@ func issueOnTheNewBus(ctx context.Context, inv *inventory.Inventory, m catalogue
 	return issueWith(ctx, inv, m, node, busAddress, known, reachable, user, password)
 }
 
+// busKindOf is what a module's bus user is recorded as: the node's tool runtime where the module is
+// the runtime (novox/hq ADR 0175), a module otherwise. The username is the same either way — the
+// runtime is issued through this same path — and the kind is what a reader of the records sees.
+func busKindOf(module string) string {
+	if module == catalogue.RuntimeModule {
+		return inventory.BusNodeTools
+	}
+	return inventory.BusModule
+}
+
 // issueWith is the delivery half: the minted password sealed to the machine as the module's broker
 // secret, and the module's consumer created where the bus can be reached. Split from the minting
 // so the move can issue every module against a bus whose address it worked out itself

cmd/mesh-controller/network.go

@@ -232,22 +232,9 @@ func network(ctx context.Context, inv *inventory.Inventory, on map[string]bool,
 	if err != nil {
 		return nil, err
 	}
-	// **A machine joining is on the network before it is anything else** (novox/hq ADR 0169). Its
-	// token was issued for its tunnel key and gave it an address, so while that token can still be
-	// used the hub carries it as a peer: it brings its tunnel up from the token and enrols over it.
-	// When the token is spent the machine is on the network by what it runs, as every other is; when
-	// it expires unused, the peer goes with it at the hub's next composition.
-	joining, err := inv.NodesWithALiveToken(ctx)
-	if err != nil {
-		return nil, err
-	}
-	isJoining := map[string]bool{}
-	for _, name := range joining {
-		isJoining[name] = true
-	}
 	nodes := make([]overlay.Node, 0, len(places))
 	for _, p := range places {
-		if !on[p.Name] && !(isJoining[p.Name] && p.Key != "" && p.Address != "") {
+		if !on[p.Name] {
 			continue
 		}
 		n := overlay.Node{

cmd/mesh-controller/nodes.go

@@ -2,11 +2,9 @@ package main
 
 import (
 	"context"
-	"encoding/base64"
 	"errors"
 	"flag"
 	"fmt"
-	"net"
 	"strings"
 	"time"
 
@@ -232,8 +230,6 @@ func tokenCommand(ctx context.Context, args []string) error {
 	validFor := set.Duration("for", time.Hour, "how long the token may be used")
 	adopted := set.Bool("adopted", false,
 		"the machine joining is in use: it is adopted, and keeps what is found on it")
-	tunnelKey := set.String("overlay-key", "",
-		"the public half of the tunnel key the machine made (`nox-mesh-host key`): it joins through the tunnel")
 	if err := set.Parse(args[1:]); err != nil {
 		return err
 	}
@@ -287,14 +283,6 @@ func tokenCommand(ctx context.Context, args []string) error {
 	default:
 		return err
 	}
-	// **Through the tunnel** (novox/hq ADR 0169): the machine's key recorded, its address given, the
-	// hub sent it as a peer — all before the token is shown, so the tunnel answers the first time the
-	// machine knocks. The bus is then reached at its address on the private network.
-	if *tunnelKey != "" {
-		if made.Tunnel, made.Broker, err = throughTheTunnel(ctx, open, issued.Node, *tunnelKey, made.Broker); err != nil {
-			return err
-		}
-	}
 	encoded, err := made.Encode()
 	if err != nil {
 		return err
@@ -319,66 +307,6 @@ func tokenCommand(ctx context.Context, args []string) error {
 	return nil
 }
 
-// throughTheTunnel makes a machine a peer of the hub for its token, and says what the token carries
-// for it: its first tunnel, and the bus at its address on the private network (novox/hq ADR 0169).
-//
-// The hub is pushed here, before the token is shown. A token shown before the hub knew the key is a
-// tunnel that does not answer, and a machine that cannot tell that from a bus that is down.
-func throughTheTunnel(ctx context.Context, open *stores, node inventory.Node, key, busAt string) (
-	*token.Tunnel, string, error) {
-	inv := open.inventory
-	key = strings.TrimSpace(key)
-	if raw, err := base64.StdEncoding.DecodeString(key); err != nil || len(raw) != 32 {
-		return nil, "", fmt.Errorf("%q is not a tunnel public key: it is 32 bytes in base64, as "+
-			"`nox-mesh-host key` prints it", key)
-	}
-	// The bus on the private network is the hub's address at the bus's own port, so the port must be
-	// known before anything is recorded.
-	_, port, err := net.SplitHostPort(busAt)
-	if err != nil || port == "" {
-		return nil, "", fmt.Errorf("the bus's address %q has no port to reach it on", busAt)
-	}
-	places, err := inv.Overlays(ctx)
-	if err != nil {
-		return nil, "", err
-	}
-	var hub *inventory.Overlay
-	for i := range places {
-		if places[i].Hub {
-			hub = &places[i]
-		}
-	}
-	if hub == nil || hub.Key == "" || hub.Endpoint == "" || hub.Address == "" {
-		return nil, "", errors.New("this mesh has no hub with a key, an address and an endpoint to " +
-			"dial, so there is no tunnel to join through: place one (`overlay place <node> --hub " +
-			"--endpoint <host>:<port>`), or issue the token without --overlay-key")
-	}
-	if err := inv.RecordOverlayKey(ctx, node.ID, key); err != nil {
-		return nil, "", err
-	}
-	if err := inv.BindTokenToKey(ctx, node.ID, key); err != nil {
-		return nil, "", err
-	}
-	cidr, err := overlayRange(ctx, inv)
-	if err != nil {
-		return nil, "", err
-	}
-	address, err := inv.AssignAddress(ctx, node.ID, cidr)
-	if err != nil {
-		return nil, "", err
-	}
-	if err := sendTo(ctx, open, []string{hub.Name}); err != nil {
-		return nil, "", fmt.Errorf("%s was made a peer of the hub, and the hub could not be sent "+
-			"it, so the tunnel would not answer — the token is not shown; issue it again once %s "+
-			"can be pushed: %w", node.Name, hub.Name, err)
-	}
-	// An address, not a name — nothing resolves before the machine has joined (novox/hq ADR 0004).
-	return &token.Tunnel{
-		Key: key, Address: address + "/32", Range: cidr,
-		HubKey: hub.Key, HubEndpoint: hub.Endpoint,
-	}, net.JoinHostPort(hub.Address, port), nil
-}
-
 // issueFor is the inventory's half of issuing a token: the record, made when it is new, adopted
 // when the operator says so, and the one-time secret for it. The node in what it returns carries
 // its mode, which is what the token says.

cmd/mesh-controller/order_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -191,7 +192,7 @@ func TestWhatAHandedOverModuleRecordsAboutItsSource(t *testing.T) {
 		t.Fatalf("the source records as %+v", from)
 	}
 	// A manifest with no provenance at all is legitimate: fixing something in a hurry.
-	if from, err := whereItComesFrom("", "", "", "", false); err != nil || from != (inventory.Source{}) {
+	if from, err := whereItComesFrom("", "", "", "", false); err != nil || !reflect.DeepEqual(from, inventory.Source{}) {
 		t.Fatalf("a manifest handed over with no provenance was refused: %+v, %v", from, err)
 	}
 	for _, c := range []struct {

cmd/mesh-controller/push.go

@@ -131,10 +131,17 @@ func serve(ctx context.Context) error {
 
 	// And the mesh's own verbs, as the seat this control plane holds (novox/hq ADR 0154). Served
 	// from the store's row, so what the seat declares is what is answered.
-	handlers, err := seatToolHandlers()
+	handlers, behind, err := seatToolHandlers()
 	if err != nil {
 		return err
 	}
+	if len(behind) > 0 {
+		// Said once, loudly, and then served anyway (novox/hq ADR 0185): the mesh keeps answering
+		// while whatever put an older control plane here is undone.
+		fmt.Printf("this control plane is behind the %s row: it cannot run %s. "+
+			"Those answer the reason when called; everything else is served as usual\n",
+			catalogue.ControllerSeatName, strings.Join(behind, ", "))
+	}
 	bus, isNATS := server.Bus().(link.OverNATS)
 	if !isNATS {
 		return errors.New("the mesh's verbs are served over the bus, and this control plane is not on it")

cmd/mesh-controller/rollout.go

@@ -346,7 +346,9 @@ func rolloutMint(ctx context.Context, again bool) error {
 			}
 			machines++
 
-		case broker.KindModule:
+		case broker.KindModule, broker.KindNodeTools:
+			// The runtime is minted and delivered exactly as a module is (novox/hq ADR 0175): it is
+			// issued as the module it stands for, to that module's `broker` secret.
 			if p.Module == "mesh-controller" {
 				// The control plane is a module too, and its `broker` secret is the old bus's
 				// credential it is still using while this runs. Writing the new bus's blob there
@@ -365,7 +367,7 @@ func rolloutMint(ctx context.Context, again bool) error {
 				skipped++
 				continue
 			}
-			password, err := inv.MintBusPassword(ctx, inventory.BusUser{Username: p.Username(), Kind: inventory.BusModule, Node: p.Node, Module: p.Module})
+			password, err := inv.MintBusPassword(ctx, inventory.BusUser{Username: p.Username(), Kind: busKindOf(p.Module), Node: p.Node, Module: p.Module})
 			if err != nil {
 				return err
 			}

cmd/mesh-controller/seatverbs.go

@@ -144,26 +144,6 @@ func argvFor(verb string, args map[string]any) ([]string, error) {
 		// Half of either shape: the command says its usage, which names both shapes, and that is
 		// the answer the caller needs.
 		return []string{"rotate"}, nil
-	case "token":
-		// `token issue` at a shell (novox/hq ADR 0169). Exactly one of node or new; the command
-		// refuses both or neither in its own words.
-		argv := []string{"token", "issue"}
-		if n := str("node"); n != "" {
-			argv = append(argv, "--node", n)
-		}
-		if n := str("new"); n != "" {
-			argv = append(argv, "--new", n)
-		}
-		if k := str("overlay_key"); k != "" {
-			argv = append(argv, "--overlay-key", k)
-		}
-		if d := str("for"); d != "" {
-			argv = append(argv, "--for", d)
-		}
-		if str("adopted") == "true" {
-			argv = append(argv, "--adopted")
-		}
-		return argv, nil
 	case "settings":
 		// `settings set|clear` at a shell (novox/hq issue 198). The values travel as an argument
 		// because a tool has no file to hand the command; the command reads either.
@@ -250,13 +230,15 @@ func runVerb(ctx context.Context, argv []string) (verbAnswer, error) {
 }
 
 // seatToolHandlers are the handlers for every verb the mesh-controller seat declares, from the
-// store's row, so a verb the row does not carry is not served and a verb it carries that this binary
-// cannot run is said at start rather than at the first call.
-func seatToolHandlers() (map[string]link.ToolHandler, error) {
+// store's row, so a verb the row does not carry is not served. A verb it carries that this binary
+// cannot run is named at start and answers the reason when called — never a refusal to serve, which
+// would take the whole control plane down for one word (novox/hq ADR 0185).
+func seatToolHandlers() (map[string]link.ToolHandler, []string, error) {
 	seat, known := catalogue.SeatNamed(catalogue.ControllerSeatName)
 	if !known {
-		return nil, fmt.Errorf("this mesh defines no %s seat", catalogue.ControllerSeatName)
+		return nil, nil, fmt.Errorf("this mesh defines no %s seat", catalogue.ControllerSeatName)
 	}
+	var behind []string
 	handlers := map[string]link.ToolHandler{}
 	for _, v := range seat.Serves {
 		verb := v.Name
@@ -267,8 +249,27 @@ func seatToolHandlers() (map[string]link.ToolHandler, error) {
 			continue
 		}
 		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)
+			// **A row ahead of this binary is not a reason to go silent.**
+			//
+			// The row is the store's and a control plane follows it (novox/hq ADR 0154), so a verb
+			// this build does not know means the row was widened by a newer one — the ordinary
+			// state of a roll-out, and of a push that put an older control plane back. Refusing to
+			// serve at all made that transient fatal: on 2026-10-02 one unknown verb took the whole
+			// mesh off the bus for ten minutes, and the way back was a human running the binary by
+			// hand, because the thing that would have repaired it is the thing that was down
+			// (novox/hq 04-ISSUES/201, ADR 0185).
+			//
+			// So the verbs this binary knows are served, and this one answers the reason instead of
+			// nothing: a caller gets a sentence naming the fault, and everything else keeps working
+			// — including the push that replaces this binary with the one whose verb it is.
+			behind = append(behind, verb)
+			reason := err
+			handlers[verb] = func(context.Context, json.RawMessage) (any, error) {
+				return nil, fmt.Errorf("%s is in this mesh's %s row and the control plane running "+
+					"here cannot run it: %w. It is a verb of a newer build; this one is behind",
+					verb, catalogue.ControllerSeatName, reason)
+			}
+			continue
 		}
 		handlers[verb] = func(ctx context.Context, raw json.RawMessage) (any, error) {
 			args := map[string]any{}
@@ -284,7 +285,7 @@ func seatToolHandlers() (map[string]link.ToolHandler, error) {
 			return runVerb(ctx, argv)
 		}
 	}
-	return handlers, nil
+	return handlers, behind, nil
 }
 
 // seatTools is what `tools` answers: every seat with a protocol, and the tools each serves, from the

cmd/mesh-controller/seatverbs_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"strings"
 	"testing"
 
@@ -73,14 +74,6 @@ func TestRotateTakesAProvisionOrAnOwnSecret(t *testing.T) {
 	}
 }
 
-// `token` is `token issue` at a shell, with the machine's tunnel key (novox/hq ADR 0169).
-func TestTokenIssuesForAMachineAndItsTunnelKey(t *testing.T) {
-	argv, err := argvFor("token", map[string]any{"new": "laptop", "overlay_key": "k", "for": "2h"})
-	if err != nil || strings.Join(argv, " ") != "token issue --new laptop --overlay-key k --for 2h" {
-		t.Fatalf("token: %v %v", argv, err)
-	}
-}
-
 // `settings` is `settings set|clear` at a shell, with the values passed inline (novox/hq issue 198).
 func TestSettingsSetsOrClearsALayer(t *testing.T) {
 	argv, err := argvFor("settings", map[string]any{"module": "dnsmasq", "values": `{"a":1}`, "node": "ace"})
@@ -138,10 +131,13 @@ func TestActsDoNotBlockTheCall(t *testing.T) {
 
 // What `tools` answers is the seats' records, with each verb's schema.
 func TestToolsAnswersTheSeatsRecords(t *testing.T) {
-	handlers, err := seatToolHandlers()
+	handlers, behind, err := seatToolHandlers()
 	if err != nil {
 		t.Fatal(err)
 	}
+	if len(behind) != 0 {
+		t.Fatalf("this build cannot run %v of its own seat's verbs", behind)
+	}
 	if len(handlers) != len(catalogue.ControllerVerbs) {
 		t.Fatalf("%d handlers for %d verbs", len(handlers), len(catalogue.ControllerVerbs))
 	}
@@ -203,3 +199,53 @@ func TestCommandRunsTheLineAsGiven(t *testing.T) {
 		t.Fatal("an unclosed quote was accepted")
 	}
 }
+
+// A verb in the row that this binary cannot run does not take the control plane off the bus: the
+// rest are served, the unknown one answers the reason, and the start-up names it (novox/hq ADR
+// 0185). One unknown word cost the mesh ten minutes of silence on 2026-10-02, recoverable only by
+// a person running the binary by hand — the push that would have repaired it needs the control
+// plane that was down.
+func TestARowAheadOfThisBuildIsServedAnyway(t *testing.T) {
+	seat, known := catalogue.SeatNamed(catalogue.ControllerSeatName)
+	if !known {
+		t.Fatal("no controller seat")
+	}
+	// The row as a newer control plane would have written it: every verb this build knows, and one
+	// it does not.
+	widened := seat
+	widened.Serves = append(append([]catalogue.Verb{}, seat.Serves...),
+		catalogue.Verb{Name: "teleport", Description: "a verb from a build that does not exist yet"})
+	rows := catalogue.DefaultSeats()
+	for i := range rows {
+		if rows[i].Name == catalogue.ControllerSeatName {
+			rows[i] = widened
+		}
+	}
+	catalogue.UseSeats(rows)
+	t.Cleanup(func() { catalogue.UseSeats(catalogue.DefaultSeats()) })
+
+	handlers, behind, err := seatToolHandlers()
+	if err != nil {
+		t.Fatalf("a row with one unknown verb refused to serve at all: %v", err)
+	}
+	if len(behind) != 1 || behind[0] != "teleport" {
+		t.Fatalf("the verbs this build cannot run were reported as %v", behind)
+	}
+	if len(handlers) != len(widened.Serves) {
+		t.Fatalf("%d handlers for %d verbs in the row", len(handlers), len(widened.Serves))
+	}
+	for _, known := range []string{"status", "nodes", "push"} {
+		if handlers[known] == nil {
+			t.Errorf("%s is not served although this build knows it", known)
+		}
+	}
+	_, err = handlers["teleport"](context.Background(), nil)
+	if err == nil {
+		t.Fatal("the unknown verb answered as though it had run")
+	}
+	for _, want := range []string{"teleport", "cannot run it", "behind"} {
+		if !strings.Contains(err.Error(), want) {
+			t.Errorf("the answer does not say %q: %v", want, err)
+		}
+	}
+}

internal/broker/agreement_catalogue_test.go

@@ -234,3 +234,13 @@ func admitsSubject(pattern, subject []string) bool {
 	}
 	return len(pattern) == len(subject)
 }
+
+// The two packages name the runtime module separately — the broker's types stay free of the
+// catalogue's on purpose — so this is what holds them to one string. A rename that reached only one
+// side would compose a runtime principal for a module nobody assigns, silently, and leave the one
+// that is assigned with a module's own grants.
+func TestTheBrokerAndTheCatalogueAgreeOnTheRuntimeModule(t *testing.T) {
+	if RuntimeModule != catalogue.RuntimeModule {
+		t.Fatalf("the broker calls the runtime %q and the catalogue %q", RuntimeModule, catalogue.RuntimeModule)
+	}
+}

internal/broker/membership_test.go

@@ -73,3 +73,37 @@ func TestAnAccountMayReadItsOwnMembershipAndNoOthers(t *testing.T) {
 	has(t, perms.Publish, "$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.anchor.postgres")
 	hasNot(t, perms.Subscribe, "mesh.assignment.>")
 }
+
+// The runtime arriving on a machine changes nothing about what each module is issued (to-be 38 WP2):
+// the memberships are composed as before and the runtime reads several of them. What the machine's
+// user list gains is one runtime principal, and loses nothing but the runtime module's own.
+func TestTheRuntimeArrivingLeavesEveryMembershipAsItWas(t *testing.T) {
+	filter := Seat{Name: "node-packet-filter", Scope: "node", Serves: []string{"rules", "reload"}}
+	three := []Declared{
+		{Module: "nftables", Holds: []Seat{filter}, Serves: []string{"firewall_rules"}},
+		{Module: "zsh", Serves: []string{"execute"}},
+		{Module: "systemd", Serves: []string{"units"}},
+	}
+	before := Records{Nodes: []string{"anchor"}, Assigned: map[string][]Declared{"anchor": three}}
+	after := Records{Nodes: []string{"anchor"}, Assigned: map[string][]Declared{
+		"anchor": append(append([]Declared{}, three...), Declared{Module: RuntimeModule}),
+	}}
+	for _, d := range three {
+		was := MembershipFor("anchor", d, PlacementsOf(before, nil))
+		is := MembershipFor("anchor", d, PlacementsOf(after, nil))
+		if !reflect.DeepEqual(was, is) {
+			t.Errorf("%s's membership changed when the runtime arrived:\n%+v\n%+v", d.Module, was, is)
+		}
+	}
+	users, err := Users(after)
+	if err != nil {
+		t.Fatal(err)
+	}
+	kinds := map[Kind]int{}
+	for _, p := range users {
+		kinds[p.Kind]++
+	}
+	if kinds[KindNodeTools] != 1 || kinds[KindModule] != 3 || kinds[KindNode] != 1 || kinds[KindController] != 1 {
+		t.Errorf("the machine's users are %v; one runtime, the three modules, the host and the controller", kinds)
+	}
+}

internal/broker/nats.go

@@ -34,8 +34,20 @@ const (
 	// authority is a list of tools and nothing else — not control, not declarations, not builds,
 	// and no ability to answer anything, because a person asks.
 	KindPerson Kind = "person"
+	// KindNodeTools is a machine's tool runtime (novox/hq ADR 0175, to-be 38): one process per
+	// node, on the host side, serving every assigned module's tools and every held seat's verbs.
+	// Its authority is the union of what the modules it carries would each have had for their
+	// tools — and nothing of what they consume, because tools are what it runs, not reactions.
+	KindNodeTools Kind = "node-tools"
 )
 
+// RuntimeModule is the module that IS the node's tool runtime (novox/hq ADR 0175). Where it is
+// assigned, the mesh composes one runtime principal for the machine in place of that module's own,
+// and the per-module containers that served tools until then stop being the way tools reach a node.
+// Mirrored in the catalogue package, which the agreement test holds to the same string; one
+// constant, so a rename is one edit and the two packages cannot drift.
+const RuntimeModule = "node-tools"
+
 // Seat is a role on the bus as a principal relates to it: the subjects it accepts, and those it
 // emits (novox/hq ADR 0118, design 29 §5).
 type Seat struct {
@@ -74,6 +86,13 @@ type Principal struct {
 	// a namespace no such module owns. Every service started and the graph stayed empty.
 	Watches []Seat
 
+	// Carries are the modules whose tools this principal serves, for a KindNodeTools principal
+	// (novox/hq ADR 0175): every module assigned to its node, as each declares itself. Its
+	// serving authority is the union of theirs — each module's own tool namespace and each held
+	// seat's verbs on this node — derived from the same declarations the modules' own principals
+	// are, so the runtime can serve nothing a module could not have served for itself.
+	Carries []Declared
+
 	// Invokes are the tools this principal may call, as `<module>.<tool>`; a single `*` is every
 	// tool. A person's whole authority (design 25 §7), and a module's only if its manifest says so
 	// (novox/hq ADR 0152) — the console's does, and nothing else's.
@@ -112,7 +131,10 @@ func (p Principal) Username() string {
 	switch p.Kind {
 	case KindPerson:
 		return "person." + p.Module
-	case KindModule:
+	case KindModule, KindNodeTools:
+		// The runtime is named exactly as the module it stands for would have been: the mesh
+		// issues its credential through the same path a module's takes (`module issue`), and
+		// that path knows the node and the module, not the kind.
 		return p.Node + "." + p.Module
 	case KindNode:
 		return "node." + p.Node
@@ -375,6 +397,48 @@ func PermissionsFor(p Principal) (Permissions, error) {
 				pub = append(pub, seatToolSubject(s, t, "*"))
 			}
 		}
+
+	case KindNodeTools:
+		// **One process serves what every module on the machine would have served for itself**
+		// (novox/hq ADR 0175). Each carried module's whole tool namespace — the same grant that
+		// module's own principal has, for the same reason: the tools a module serves are what its
+		// code answers, and a list here would be a second copy of it. Each held seat's verbs on
+		// this node, as the holder's own principal would be granted them.
+		for _, d := range p.Carries {
+			if !safeSubject.MatchString(d.Module) {
+				return Permissions{}, fmt.Errorf(
+					"%q cannot be part of a subject: a permission is a subject pattern, and this would widen it", d.Module)
+			}
+			own := "mesh.mod." + d.Module
+			sub = append(sub, own+".tool.>")
+			// A tool that emits an event is the module's code and emits under the module's name
+			// (ADR 0042); the runtime carrying that code may publish what the module declared it
+			// emits, and nothing it did not.
+			for _, e := range d.Emits {
+				pub = append(pub, own+".event."+e)
+			}
+			for _, s := range d.Holds {
+				for _, t := range s.Serves {
+					sub = append(sub, seatToolSubject(s, t, p.Node))
+				}
+			}
+		}
+		// Every assigned module's membership on this node (ADR 0160): one per module, read
+		// directly from the stream and followed live. This node's and no other's — the one token
+		// that varies is the module, so the pattern is the machine's own assignments.
+		sub = append(sub, "mesh.assignment."+p.Node+".*")
+		pub = append(pub, "$JS.API.DIRECT.GET."+AssignmentsStream+".mesh.assignment."+p.Node+".*")
+		// And every tool on the mesh (ADR 0175, decision 5): any node may call any tool on any
+		// node, as the console already could — the runtime is the console's serving mode.
+		invoked, err := invokedSubjects([]string{"*"})
+		if err != nil {
+			return Permissions{}, err
+		}
+		pub = append(pub, invoked...)
+		// Nothing about consumers: it consumes nothing. A module's reactions to events are its
+		// own long-lived process, which ADR 0175 leaves where it is; what moves here is tools.
+		sub = unique(sub)
+		pub = unique(pub)
 	}
 
 	if p.Kind == KindPerson {
@@ -382,6 +446,11 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		// consumer, because nothing is delivered to a person — they ask and are answered.
 		sub = append(sub, p.inbox())
 	}
+	if p.Kind == KindNodeTools {
+		// Its reply space, so the answers to what its tools call come back to it. No ack subject
+		// for the same reason a person has none: nothing is delivered to it.
+		sub = append(sub, p.inbox())
+	}
 
 	if p.Kind == KindModule || p.Kind == KindNode || p.Kind == KindController {
 		// Its own reply space, and nothing wider.
@@ -403,7 +472,7 @@ func PermissionsFor(p Principal) (Permissions, error) {
 		// A module answers what it was asked — a tool call reaches it on its own namespace, so the
 		// authority is bounded by having been asked — and so does the controller. A node and a
 		// person are never asked anything, and are granted nothing here.
-		AllowResponses: p.Kind == KindModule || p.Kind == KindController,
+		AllowResponses: p.Kind == KindModule || p.Kind == KindController || p.Kind == KindNodeTools,
 	}, nil
 }
 
@@ -625,6 +694,20 @@ func ComposeAccounts(principals []Principal) (string, error) {
 	return b.String(), nil
 }
 
+// unique is a sorted list with each subject once. Two carried modules holding seats with the same
+// verb, or the runtime module itself carried beside the others, would otherwise write a grant twice
+// — harmless to the server, and noise in a file that is read as the mesh's authority model.
+func unique(values []string) []string {
+	sort.Strings(values)
+	out := values[:0]
+	for i, v := range values {
+		if i == 0 || v != values[i-1] {
+			out = append(out, v)
+		}
+	}
+	return out
+}
+
 func quoted(values []string) string {
 	if len(values) == 0 {
 		return ""

internal/broker/nats_test.go

@@ -371,3 +371,73 @@ func TestAModulePullsItsOwnConsumerAndNoOthers(t *testing.T) {
 		}
 	}
 }
+
+// The runtime's authority is the union of what the modules it carries would have been granted for
+// their tools (novox/hq ADR 0175): every carried module's tool namespace, every held seat's verbs
+// on this node, every module's membership on this node, and a call to anything. Nothing it
+// consumes, because it reacts to nothing.
+func TestTheRuntimeServesTheUnionAndConsumesNothing(t *testing.T) {
+	filter := Seat{Name: "node-packet-filter", Scope: "node", Serves: []string{"rules", "reload"}}
+	p := Principal{Kind: KindNodeTools, Node: "anchor", Module: RuntimeModule, Carries: []Declared{
+		{Module: "nftables", Holds: []Seat{filter}, Serves: []string{"firewall_rules"}},
+		{Module: "zsh", Emits: []string{"shell.opened"}, Consumes: []string{"shop.order.placed"}},
+		{Module: RuntimeModule},
+	}}
+	perms, err := PermissionsFor(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{
+		"mesh.mod.nftables.tool.>", "mesh.mod.zsh.tool.>", "mesh.mod." + RuntimeModule + ".tool.>",
+		"mesh.seat.node-packet-filter.tool.rules.anchor", "mesh.seat.node-packet-filter.tool.reload.anchor",
+		"mesh.assignment.anchor.*",
+		"_INBOX.anchor." + RuntimeModule + ".>",
+	} {
+		if !contains(perms.Subscribe, want) {
+			t.Errorf("the runtime may not subscribe %s: %v", want, perms.Subscribe)
+		}
+	}
+	for _, want := range []string{
+		"mesh.mod.*.tool.>", "mesh.seat.*.tool.>",
+		"$JS.API.DIRECT.GET.ASSIGNMENTS.mesh.assignment.anchor.*",
+		"mesh.mod.zsh.event.shell.opened",
+	} {
+		if !contains(perms.Publish, want) {
+			t.Errorf("the runtime may not publish %s: %v", want, perms.Publish)
+		}
+	}
+	// Nothing of what a carried module consumes, and no consumer of its own to ack.
+	for _, s := range perms.Subscribe {
+		if strings.Contains(s, ".event.") || strings.HasPrefix(s, "_DELIVER.") {
+			t.Errorf("the runtime was granted a delivery it has no consumer for: %s", s)
+		}
+	}
+	for _, s := range perms.Publish {
+		if strings.HasPrefix(s, "$JS.ACK.") || strings.Contains(s, "CONSUMER") {
+			t.Errorf("the runtime was granted a consumer's subject and has no consumer: %s", s)
+		}
+	}
+	if !perms.AllowResponses {
+		t.Error("the runtime answers what it is asked, and may not reply")
+	}
+	if _, needed := ConsumerFor(p); needed {
+		t.Error("a consumer would be made for the runtime, which consumes nothing")
+	}
+	// Each subject once: the file is read as the mesh's authority model.
+	seen := map[string]bool{}
+	for _, s := range append(append([]string{}, perms.Subscribe...), perms.Publish...) {
+		if seen[s] {
+			t.Errorf("%s is granted twice", s)
+		}
+		seen[s] = true
+	}
+}
+
+func contains(list []string, want string) bool {
+	for _, s := range list {
+		if s == want {
+			return true
+		}
+	}
+	return false
+}

internal/broker/users.go

@@ -62,13 +62,33 @@ func Users(r Records) ([]Principal, error) {
 
 	for _, node := range sortedCopy(r.Nodes) {
 		out = append(out, Principal{Kind: KindNode, Node: node})
+		// **Where the runtime is assigned, the machine gets one runtime principal in place of the
+		// runtime module's own** (novox/hq ADR 0175, to-be 38). It carries every module on the
+		// node: its serving grants are the union of theirs. Every other module keeps its own
+		// principal — a module still serving tools from its own container holds its own
+		// credential until it moves, and the two serve side by side in the meantime.
+		runtimeHere := false
 		for _, d := range r.Assigned[node] {
+			if d.Module == RuntimeModule {
+				runtimeHere = true
+			}
+		}
+		for _, d := range r.Assigned[node] {
+			if runtimeHere && d.Module == RuntimeModule {
+				continue
+			}
 			out = append(out, Principal{
 				Kind: KindModule, Node: node, Module: d.Module,
 				Emits: d.Emits, Consumes: d.Consumes, Serves: d.Serves,
 				Holds: d.Holds, Uses: d.Uses, Watches: d.Watches, Invokes: d.Invokes,
 			})
 		}
+		if runtimeHere {
+			out = append(out, Principal{
+				Kind: KindNodeTools, Node: node, Module: RuntimeModule,
+				Carries: append([]Declared(nil), r.Assigned[node]...),
+			})
+		}
 	}
 	for _, node := range sortedCopy(r.Enrolling) {
 		out = append(out, Principal{Kind: KindEnrolment, Node: node})

internal/broker/users_test.go

@@ -245,3 +245,54 @@ func TestAUserListIsComposedBeforeAnythingMovesOntoTheBus(t *testing.T) {
 		t.Errorf("the composed list does not contain the machine running the bus")
 	}
 }
+
+// Where the runtime module is assigned, the machine gets one runtime principal in place of the
+// runtime module's own (novox/hq ADR 0175, to-be 38). Every other module keeps its own: a module
+// still serving tools from its own container holds its own credential until it moves.
+func TestTheRuntimeModuleBecomesTheMachinesRuntimePrincipal(t *testing.T) {
+	r := someRecords()
+	r.Assigned["one"] = append(r.Assigned["one"], Declared{Module: RuntimeModule})
+	users, err := Users(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var runtime *Principal
+	for i := range users {
+		p := &users[i]
+		if p.Node == "one" && p.Module == RuntimeModule {
+			if p.Kind == KindModule {
+				t.Fatalf("%s on one was composed as an ordinary module beside the runtime", RuntimeModule)
+			}
+			runtime = p
+		}
+	}
+	if runtime == nil || runtime.Kind != KindNodeTools {
+		t.Fatalf("one runs %s and got no runtime principal: %v", RuntimeModule, namesOf(t, r))
+	}
+	if runtime.Username() != "one."+RuntimeModule {
+		t.Errorf("the runtime is named %q; `module issue` names it as the module it stands for", runtime.Username())
+	}
+	carried := map[string]bool{}
+	for _, d := range runtime.Carries {
+		carried[d.Module] = true
+	}
+	if !carried["telegram"] || !carried[RuntimeModule] {
+		t.Errorf("the runtime carries %v; it carries every module on its node", carried)
+	}
+	// And the other node, where the runtime is not assigned, is exactly as before.
+	for _, p := range users {
+		if p.Node == "two" && p.Kind == KindNodeTools {
+			t.Fatal("two runs no runtime and was given a runtime principal")
+		}
+	}
+	// A module serving its own tools beside the runtime keeps its own principal.
+	found := false
+	for _, p := range users {
+		if p.Kind == KindModule && p.Node == "one" && p.Module == "telegram" {
+			found = true
+		}
+	}
+	if !found {
+		t.Error("telegram lost its own principal when the runtime arrived on its node")
+	}
+}

internal/builder/toolchain.go

@@ -107,10 +107,16 @@ var toolchains = []Toolchain{
 		// symlinks to a launcher that requires its library relatively — and the base image's own
 		// assembly resolves them away, leaving a launcher whose relative require points nowhere.
 		// Every module's hand-written Dockerfile had to know this. Now none of them does.
+		// **Rooted at the module, so an entrypoint lands where it is named.** Without a root the
+		// compiler takes the common directory of the files it is given: a module compiling only
+		// `tools/index.ts` had its output at `index.js`, and the entrypoint it declared —
+		// `tools/index.js`, "named as it will be found" — named a file the bundle did not
+		// contain. The runtime that loads bundles by their declared entrypoints (novox/hq ADR
+		// 0175) is what made this visible.
 		Compile: []string{
 			"node", "/app/node_modules/typescript/bin/tsc",
 			"--module", "NodeNext", "--moduleResolution", "NodeNext",
-			"--target", "ES2022",
+			"--target", "ES2022", "--rootDir", ".",
 		},
 		OutputFlag: "--outDir",
 		Unit:       UnitSources,

internal/catalogue/build.go

@@ -67,6 +67,31 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
 	out := m
 	out.Build = nil
 	out.Resources = nil
+	// What the build compiled, kept on the resolved manifest (novox/hq ADR 0175): a tools bundle is
+	// named by no resource of the module's own — the node's runtime loads it — so this is the only
+	// place the mesh would otherwise not have it. In artifact order, so two resolutions of one
+	// build compare equal.
+	out.Bundles = nil
+	if m.Build != nil {
+		for _, a := range m.Build.Artifacts {
+			if a.Kind != ArtifactBundle {
+				continue
+			}
+			made := by[a.Name]
+			// What the runtime loads: what the artifact said, else every entrypoint of a module
+			// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
+			loads := append([]string(nil), a.Loads...)
+			if a.Loads == nil && len(m.Tools) > 0 {
+				loads = append([]string(nil), a.Entrypoints...)
+			}
+			out.Bundles = append(out.Bundles, Bundle{
+				Name: a.Name, Source: made.Reference, Digest: made.Digest,
+				Language: a.Language, Entrypoints: append([]string(nil), a.Entrypoints...),
+				Loads: loads,
+			})
+		}
+		sort.Slice(out.Bundles, func(i, j int) bool { return out.Bundles[i].Name < out.Bundles[j].Name })
+	}
 	for _, r := range m.Resources {
 		named, _ := r["artifact"].(string)
 		if named == "" {
@@ -191,6 +216,20 @@ func (b *Build) problems(module string) []string {
 					"%s: %q is a bundle and says no language, so nothing can choose a compiler "+
 						"for it", module, a.Name))
 			}
+			// What the runtime loads is among what was compiled (ADR 0175): a name here that is
+			// not an entrypoint is a file the bundle does not contain, and the runtime would
+			// fail to import it on every machine rather than here.
+			for _, load := range a.Loads {
+				found := false
+				for _, e := range a.Entrypoints {
+					found = found || e == load
+				}
+				if !found {
+					problems = append(problems, fmt.Sprintf(
+						"%s: %q says the runtime loads %q, which is not among its entrypoints — "+
+							"what is loaded is compiled, so it is named there too", module, a.Name, load))
+				}
+			}
 			// **A system, for a language that compiles to a binary** (novox/hq ADR 0142). A binary
 			// is pinned to one operating system at link time so a host refuses to touch a machine
 			// it was not built for (novox/hq ADR 0005); an artifact that says nothing would be

internal/catalogue/declaration.go

@@ -512,6 +512,13 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 				"id": NeedID(name), "type": "file", "path": m.OwnSecrets[name].Path, "sealed": sealed,
 			}))
 		}
+		// This module's tools bundles, where the machine runs the node's tool runtime (novox/hq
+		// ADR 0175, to-be 38 WP2). Mesh-computed like everything above it, and before the module's
+		// own resources for the same reason: the runtime's process names the files inside these
+		// and is restarted when one changes, so they are on the machine before it is.
+		if r.runtimeHere() {
+			first = append(first, bundleArchives(m)...)
+		}
 		// Operator-owned paths this module is granted use of (novox/hq ADR 0051). Written before
 		// the module's own resources, and so before the container that mounts them: the host must
 		// find each present — refusing clearly if the operator has not provided it — before it
@@ -885,6 +892,17 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 			out = append(out, fact)
 		}
 	}
+	// The node's tool runtime, last (novox/hq ADR 0175, to-be 38 WP2.3): one process loading every
+	// bundle delivered above and holding the credential sealed above, so both exist before it starts
+	// — the order written here is the order the machine applies.
+	if r.runtimeHere() {
+		process, err := r.runtimeProcess(with)
+		if err != nil {
+			return nil, err
+		}
+		owner[fmt.Sprint(process["id"])] = RuntimeModule
+		out = append(out, process)
+	}
 	if with.Adopted {
 		// First, before anything a module declares: what the mesh needs reachable, then its guard.
 		// The order a machine applies is the order written here.

internal/catalogue/manifest.go

@@ -572,6 +572,36 @@ type Manifest struct {
 	// a module that could ask for it could read every credential on the bus — and the claim on
 	// `mesh-broker` is what authorises it, checked from this manifest alone.
 	BusUsers string `json:"bus-users,omitempty"`
+
+	// Bundles are this module's compiled bundles as the build produced them: what each is called,
+	// where it is, what it hashes to, what language it is in and which files a tool runtime loads
+	// from it (novox/hq ADR 0175, to-be 38).
+	//
+	// **Derived, never written.** The manifest in a repository says `build.artifacts`; the manifest
+	// the mesh holds says what came out, the way a resource naming an artifact comes to name a
+	// digest. Kept here because a tools bundle is referenced by no resource of the module's own —
+	// the node's runtime loads it, and the runtime is composed by the mesh — so without this the
+	// resolved manifest would carry no trace of the one artifact the runtime needs. A repository
+	// manifest that writes this beside a build is refused: it would be stating the build's output
+	// by hand.
+	Bundles []Bundle `json:"bundles,omitempty"`
+}
+
+// Bundle is one compiled bundle after it exists, as the resolved manifest carries it.
+type Bundle struct {
+	Name string `json:"name"`
+	// Source is where a machine fetches it, kept without the store's address like every reference
+	// the mesh records (artifacts.go); Digest is what it must hash to.
+	Source string `json:"source"`
+	Digest string `json:"digest"`
+	// Language is what it was compiled from, which is what says how it is run.
+	Language string `json:"language,omitempty"`
+	// Entrypoints are the compiled files it was built around, relative to its root.
+	Entrypoints []string `json:"entrypoints,omitempty"`
+	// Loads are the entrypoints a node's tool runtime imports from it: what the artifact said, or
+	// every entrypoint for a module declaring tools that said nothing. Empty for a bundle that is
+	// run rather than loaded.
+	Loads []string `json:"loads,omitempty"`
 }
 
 // Build says how to produce this module's artifacts from its source.
@@ -708,6 +738,16 @@ type Artifact struct {
 	// somebody adds a helper. An empty list is a bundle that is run rather than loaded — a
 	// provisioner or a step, named by whatever runs it.
 	Entrypoints []string `json:"entrypoints,omitempty"`
+
+	// Loads are the entrypoints of this bundle the node's tool runtime loads (novox/hq ADR 0175,
+	// to-be 38): the module's tool code, each file registering its tools as it is imported. A
+	// subset of Entrypoints, for a bundle that also carries things that are RUN — a daemon, a
+	// step, a report — and must not have them imported into the runtime.
+	//
+	// Absent means every entrypoint, for a module that declares `tools`: a bundle holding the
+	// module's tools and nothing else is the ordinary case and should not have to say the same
+	// list twice. A module declaring no tools has nothing the runtime loads, whatever it compiles.
+	Loads []string `json:"loads,omitempty"`
 }
 
 // Kinds an artifact may be.
@@ -1333,6 +1373,15 @@ func ParseManifest(raw []byte) (Manifest, error) {
 	//
 	// Refused here because the alternative is a build that never returns, on a mesh new enough
 	// that nobody is watching it yet.
+	if m.Build != nil && len(m.Bundles) > 0 {
+		// The output of a build, written beside the build that produces it (ADR 0175). A resource
+		// naming a digest beside an `artifact` would be the same mistake, and is caught the same way:
+		// what the mesh derives, a repository does not state.
+		problems = append(problems, fmt.Sprintf(
+			"%s writes `bundles` beside its build. The mesh derives that from what the build "+
+				"produced; a manifest states `build.artifacts` and nothing about what came out",
+			m.Module))
+	}
 	if m.Build != nil && len(m.Build.Artifacts) > 0 {
 		for _, o := range m.Offers() {
 			if o != ArtifactStoreProvision {

internal/catalogue/runtime.go

@@ -0,0 +1,251 @@
+package catalogue
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// The node's tool runtime, as the catalogue knows it (novox/hq ADR 0175, to-be 38).
+//
+// **One module is the runtime.** Where it is assigned, one process per machine serves every assigned
+// module's tools and every held seat's verbs, on the host side, from the bundles each module's build
+// produced — and no module needs a container to reach the bus with its tools. The name is a constant
+// rather than a manifest field because a rule turns on it: the composer places the runtime's process
+// where this module is, and registration refuses the old pattern once this module exists.
+
+// RuntimeModule is the module that is the node's tool runtime. Mirrored in the broker package,
+// which composes a principal of its own for it; the agreement test there holds the two to one string.
+const RuntimeModule = "node-tools"
+
+// BundleRoot is where a machine keeps the tools bundles the mesh delivers to it: under the mesh's
+// own directory, beside the daemons the host unpacks there, and never where a package manager also
+// writes. One directory per module, one per bundle beneath it, at a path that does not move with
+// the version — so the runtime's process names each entrypoint once and is restarted, not
+// recomposed, when a bundle changes.
+const BundleRoot = "/var/lib/mesh/bundles"
+
+// BundleID names the archive resource that delivers one of a module's bundles; prefixed with the
+// module like every resource of its own.
+func BundleID(bundle string) string { return "bundle-" + bundle }
+
+// BundlePath is where one module's bundle is unpacked on a machine.
+func BundlePath(module, bundle string) string { return BundleRoot + "/" + module + "/" + bundle }
+
+// runtimeHere says whether this node's set includes the runtime module, which is what decides
+// whether anything about tools changes on the machine (to-be 38 WP2): until the runtime is assigned,
+// a node is sent exactly what it was sent before, bundles included, because a bundle nothing loads
+// is bytes nobody reads.
+func (r Resolution) runtimeHere() bool {
+	for _, m := range r.Modules {
+		if m.Module == RuntimeModule {
+			return true
+		}
+	}
+	return false
+}
+
+// bundleArchives is one archive per tools bundle of a module — a bundle the runtime LOADS something
+// from — as the host fetches and unpacks any artifact (novox/hq ADR 0175 §3: a module brings its
+// tools as a bundle, delivered by the host like any artifact, never an image). A bundle it loads
+// nothing from is run rather than loaded: a daemon, a step, the runtime itself — delivered by the
+// process that runs it, and not again here.
+//
+// The source is the kept reference; the per-resource pass that follows routes it through the
+// artifact store as this network reaches it now, as it does every image and archive the mesh built.
+func bundleArchives(m Manifest) []map[string]any {
+	var out []map[string]any
+	for _, b := range m.Bundles {
+		if len(b.Loads) == 0 {
+			continue
+		}
+		out = append(out, map[string]any{
+			"id": BundleID(b.Name), "type": "archive",
+			"source": b.Source, "digest": b.Digest,
+			"path": BundlePath(m.Module, b.Name),
+		})
+	}
+	return out
+}
+
+// RuntimeProcessID names the one process the mesh composes for a machine's runtime; prefixed with
+// the runtime module like a resource of its own, because that module is what the host sees it as.
+func RuntimeProcessID() string { return "runtime" }
+
+// RuntimeToolModules is the variable the runtime reads the modules it serves from: one
+// `<module>=<entrypoint>` per file it loads, comma-separated — several entries may name one module.
+// RuntimeBrokerFile is where it reads the node's credential; RuntimeOperatorAccount and
+// RuntimeOperatorHome are the machine's operator account and home, handed to every tool's
+// environment (to-be 38 WP1), and absent on a machine with no account.
+const (
+	RuntimeToolModules     = "MESH_TOOL_MODULES"
+	RuntimeBrokerFile      = "MESH_BROKER_FILE"
+	RuntimeOperatorAccount = "MESH_OPERATOR_ACCOUNT"
+	RuntimeOperatorHome    = "MESH_OPERATOR_HOME"
+)
+
+// interpreterFor is how a bundle in a language is run: the program the host's unit starts, with the
+// bundle's entrypoint after it. The one thing the composer takes from a language, and said here
+// rather than in a manifest because the runtime's process is the mesh's to compose (to-be 38 WP3).
+func interpreterFor(language string) (string, error) {
+	switch language {
+	case "typescript":
+		return "node", nil
+	}
+	return "", fmt.Errorf(
+		"%s is written in %q, and the mesh knows no interpreter to run a %q bundle with",
+		RuntimeModule, language, language)
+}
+
+// runtimeProcess is the one process a machine runs the node's tool runtime as (novox/hq ADR 0175,
+// to-be 38 WP2.3): the runtime module's own bundle, run by its language's interpreter, told which
+// modules it serves and from which files, where its credential is, and who the machine's operator
+// is — and restarted when any bundle it loads or the credential it holds changes.
+//
+// Composed from the placed manifests, so the credential's path is where this node puts it. The
+// runtime runs as the operator's account when the machine has one, which is what lets a tool that
+// needs root escalate as the operator would (ADR 0175 §4); on a machine with no account it runs as
+// root, and the two operator words are not set.
+func (r Resolution) runtimeProcess(with Rendering) (map[string]any, error) {
+	var runtime *Manifest
+	for i := range r.Modules {
+		if r.Modules[i].Module == RuntimeModule {
+			runtime = &r.Modules[i]
+		}
+	}
+	if runtime == nil {
+		return nil, nil
+	}
+	if len(runtime.Bundles) != 1 {
+		return nil, fmt.Errorf(
+			"%s is assigned to %s and its build produced %d bundle(s); the runtime is one bundle "+
+				"the mesh runs, so the module declares exactly one (novox/hq to-be 38)",
+			RuntimeModule, r.Node, len(runtime.Bundles))
+	}
+	bundle := runtime.Bundles[0]
+	if len(bundle.Entrypoints) != 1 {
+		return nil, fmt.Errorf(
+			"%s's bundle %q names %d entrypoint(s); the runtime is run from one, so the module "+
+				"declares exactly one (novox/hq to-be 38)", RuntimeModule, bundle.Name, len(bundle.Entrypoints))
+	}
+	interpreter, err := interpreterFor(bundle.Language)
+	if err != nil {
+		return nil, err
+	}
+	credential, declared := runtime.OwnSecrets["broker"]
+	if !declared {
+		return nil, fmt.Errorf(
+			"%s declares no own secret named broker, and the node's credential is delivered there: "+
+				"a module that speaks on the bus declares \"own-secrets\": {\"broker\": <path>}",
+			RuntimeModule)
+	}
+
+	// What it serves, and from which files: every module on this machine that composes here, in
+	// name order, each bundle it loads from in the order the manifest gave. A module left out of
+	// the declaration — a filter on an adopted machine — is left out of this too, or the runtime
+	// would be told to load files that were never delivered.
+	var served []string
+	var restartOn []string
+	for _, m := range r.Modules {
+		if with.Adopted && m.Filtering != nil {
+			continue
+		}
+		for _, b := range m.Bundles {
+			if len(b.Loads) == 0 {
+				continue
+			}
+			for _, load := range b.Loads {
+				served = append(served, m.Module+"="+BundlePath(m.Module, b.Name)+"/"+load)
+			}
+			restartOn = append(restartOn, m.Module+"."+BundleID(b.Name))
+		}
+	}
+	sort.Strings(served)
+	restartOn = append(restartOn, RuntimeModule+"."+NeedID("broker"))
+	sort.Strings(restartOn)
+
+	env := map[string]string{
+		RuntimeToolModules: strings.Join(served, ","),
+		RuntimeBrokerFile:  credential.Path,
+	}
+	process := map[string]any{
+		"id": RuntimeModule + "." + RuntimeProcessID(), "type": "process", "name": RuntimeModule,
+		"source": bundle.Source, "digest": bundle.Digest,
+		"run":        []any{interpreter, bundle.Entrypoints[0]},
+		"env":        env,
+		"restart-on": toAny(restartOn),
+	}
+	if r.Account != "" {
+		env[RuntimeOperatorAccount] = r.Account
+		env[RuntimeOperatorHome] = accountHomeOf(r.Account, r.AccountHome)
+		process["user"] = r.Account
+	}
+	// Routed through the artifact store as this network reaches it now, like everything the mesh
+	// built; refused with the same words when there is no store to route through.
+	if err := artifactsInto(process, RuntimeModule, with); err != nil {
+		return nil, err
+	}
+	return process, nil
+}
+
+func toAny(in []string) []any {
+	out := make([]any, 0, len(in))
+	for _, s := range in {
+		out = append(out, s)
+	}
+	return out
+}
+
+// RuntimeImageModule and RuntimeImageArtifact name the image every per-module tool container was
+// built on: the tool runtime's own runtime image. With the runtime a module of its own, that image
+// stays the way a module's SERVICE may be built and stops being the way tools reach a node (ADR 0175).
+const (
+	RuntimeImageModule   = "mesh-tools"
+	RuntimeImageArtifact = "runtime"
+)
+
+// ToolContainerOnTheRuntime says why a manifest is the pattern ADR 0175 retires — a module whose tools
+// are served from a container built on the tool runtime's image — or nothing when it is not. Judged
+// from the manifest's own `build.on` when it is a repository manifest, and from what its build stood
+// on when it is a built one, because a resolved manifest carries no build. The gate itself is
+// registration's (to-be 38 WP2.4): once the runtime module is in the catalogue, this is refused.
+//
+// Three things must hold, and each alone is fine: declaring tools (a bundle does that); a container
+// (a module's service may well be one); building on the runtime's image (a service written against
+// the SDK may). All three is a container whose purpose is tools, which the runtime now serves.
+func ToolContainerOnTheRuntime(m Manifest, against []string) string {
+	if len(m.Tools) == 0 {
+		return ""
+	}
+	container := false
+	for _, r := range m.Resources {
+		if fmt.Sprint(r["type"]) == "container" {
+			container = true
+		}
+	}
+	if !container {
+		return ""
+	}
+	onTheRuntime := false
+	if m.Build != nil {
+		for _, on := range m.Build.On {
+			if on.Module == RuntimeImageModule && on.Artifact == RuntimeImageArtifact {
+				onTheRuntime = true
+			}
+		}
+	}
+	for _, ref := range against {
+		path, kept := InArtifactStore(Recorded(ref))
+		if kept && strings.HasPrefix(path, RuntimeImageModule+"/"+RuntimeImageArtifact+"@") {
+			onTheRuntime = true
+		}
+	}
+	if !onTheRuntime {
+		return ""
+	}
+	return fmt.Sprintf(
+		"%s declares tools and a container built on %s's %s image — a container whose purpose is "+
+			"serving tools. The node's tool runtime (%s) serves every module's tools from its bundle "+
+			"now (novox/hq ADR 0175, to-be 38); declare the tools as a bundle and drop the container",
+		m.Module, RuntimeImageModule, RuntimeImageArtifact, RuntimeModule)
+}

internal/catalogue/runtime_gate_test.go

@@ -0,0 +1,88 @@
+package catalogue
+
+import (
+	"strings"
+	"testing"
+)
+
+// The packet-filter manifest as it was the day the runtime was decided (novox/hq ADR 0175): tools,
+// served from a container built on the tool runtime's image, with NET_ADMIN so the container could
+// reach the filter. The exact pattern to-be 38 WP4 moves it off, and the one the gate refuses.
+const thePacketFilterAsItWas = `{
+  "module": "nftables",
+  "version": "1",
+  "capabilities": ["firewall", "container-runtime"],
+  "claims": [{"name": "node-packet-filter", "scope": "node", "serves": ["rules", "reload", "remove"]}],
+  "filtering": {"into": "/etc/nftables.conf"},
+  "resources": [
+    {"id": "mesh-state", "type": "directory", "mode": "0700", "place": "mesh"},
+    {"id": "package", "type": "package", "package": "nftables"},
+    {"id": "unit", "type": "file", "path": "/etc/systemd/system/mesh-filter.service",
+     "content": "[Unit]\nDescription=The mesh's packet filter\n[Service]\nType=oneshot\nExecStart=nft -f /etc/nftables.conf\n", "mode": "0644"},
+    {"id": "load", "type": "service", "unit": "mesh-filter.service", "state": "running", "boot": "enabled",
+     "restart-on": ["unit"], "reload-on": ["filtering"]},
+    {"id": "runtime", "type": "container", "name": "mesh-nftables", "network": "host",
+     "capabilities": ["NET_ADMIN"],
+     "volumes": ["${dir:mesh-state}/broker:/run/secrets/broker:ro", "/etc/nftables.conf:/etc/nftables.conf:ro"],
+     "env": {"MESH_BROKER_FILE": "/run/secrets/broker", "MESH_FILTER_FILE": "/etc/nftables.conf"},
+     "artifact": "runtime"}
+  ],
+  "tools": ["firewall_rules"],
+  "own-secrets": {"broker": "${dir:mesh-state}/broker"},
+  "build": {
+    "on": [
+      {"arg": "BUILD_BASE", "module": "mesh-tools", "artifact": "build"},
+      {"arg": "RUNTIME_BASE", "module": "mesh-tools", "artifact": "runtime"}
+    ],
+    "artifacts": [{"name": "runtime", "kind": "image", "from": "Dockerfile"}]
+  }
+}`
+
+func TestAToolContainerOnTheRuntimeImageIsNamedForWhatItIs(t *testing.T) {
+	m, err := ParseManifest([]byte(thePacketFilterAsItWas))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// From the repository: the manifest says what it builds on.
+	why := ToolContainerOnTheRuntime(m, nil)
+	if why == "" {
+		t.Fatal("the packet filter's tool container was not recognised from its build")
+	}
+	for _, word := range []string{"nftables", "mesh-tools", "runtime", "ADR 0175", "bundle"} {
+		if !strings.Contains(why, word) {
+			t.Errorf("the refusal does not say %q: %s", word, why)
+		}
+	}
+
+	// Built: the manifest carries no build, and what it stood on says the same.
+	built, err := m.Resolve([]Built{{Name: "runtime", Kind: ArtifactImage,
+		Reference: ArtifactStoreScheme + "nftables/runtime@" + digest}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	stoodOn := []string{"anchor.internal:5100/mesh-tools/build@" + digest, "anchor.internal:5100/mesh-tools/runtime@" + digest}
+	if ToolContainerOnTheRuntime(built, stoodOn) == "" {
+		t.Error("the packet filter's tool container was not recognised from what its build stood on")
+	}
+	if ToolContainerOnTheRuntime(built, nil) != "" {
+		t.Error("a built manifest with no record of its base was judged to be on the runtime")
+	}
+
+	// Each of the three alone is an ordinary module.
+	bundle := m
+	bundle.Resources = m.Resources[:len(m.Resources)-1]
+	if ToolContainerOnTheRuntime(bundle, nil) != "" {
+		t.Error("a module with tools and no container is the pattern the runtime serves, and was refused")
+	}
+	service := m
+	service.Tools = nil
+	if ToolContainerOnTheRuntime(service, nil) != "" {
+		t.Error("a service built against the SDK, declaring no tools, was refused")
+	}
+	elsewhere := m
+	elsewhere.Build = &Build{On: []BuildsOn{{Arg: "NODE_BASE", Image: "node@" + digest}},
+		Artifacts: m.Build.Artifacts}
+	if ToolContainerOnTheRuntime(elsewhere, nil) != "" {
+		t.Error("a tool container on a public base was refused as though it were on the runtime's")
+	}
+}

internal/catalogue/runtime_test.go

@@ -0,0 +1,204 @@
+package catalogue
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+// The node's tool runtime (novox/hq ADR 0175, to-be 38): where the runtime module is assigned, a
+// machine is sent every assigned module's tools bundle as an archive, and the runtime's own process
+// loading them. Where it is not, the machine is sent exactly what it was sent before.
+
+var bundleDigest = "sha256:" + strings.Repeat("b", 64)
+
+// aToolsModule is a module whose tools come as a compiled bundle and nothing else — the shape every
+// module takes once its tool container goes (to-be 38 WP4).
+func aToolsModule(t *testing.T, name string, entrypoints ...string) Manifest {
+	t.Helper()
+	m := Manifest{Module: name, Version: "1", Tools: []string{"status"},
+		Build: &Build{Artifacts: []Artifact{
+			{Name: "tools", Kind: ArtifactBundle, Language: "typescript", Entrypoints: entrypoints},
+		}}}
+	resolved, err := m.Resolve([]Built{{Name: "tools", Kind: ArtifactBundle,
+		Reference: ArtifactStoreScheme + name + "/tools/blobs/" + bundleDigest, Digest: bundleDigest}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return resolved
+}
+
+// theRuntime is the runtime module as the catalogue holds it: its own bundle, run rather than
+// loaded, and its broker secret to receive the node's credential in.
+func theRuntime(t *testing.T) Manifest {
+	t.Helper()
+	m := Manifest{Module: RuntimeModule, Version: "1",
+		OwnSecrets: OwnSecrets{"broker": {Path: "/var/lib/mesh/" + RuntimeModule + "/broker"}},
+		Build: &Build{Artifacts: []Artifact{{Name: "runtime", Kind: ArtifactBundle, Language: "typescript",
+			Entrypoints: []string{"src/main.js"}}}}}
+	resolved, err := m.Resolve([]Built{{Name: "runtime", Kind: ArtifactBundle,
+		Reference: ArtifactStoreScheme + RuntimeModule + "/runtime/blobs/" + bundleDigest, Digest: bundleDigest}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return resolved
+}
+
+func TestABuildsBundlesAreCarriedOnTheResolvedManifest(t *testing.T) {
+	m := aToolsModule(t, "nftables", "tools/index.js")
+	if len(m.Bundles) != 1 {
+		t.Fatalf("the resolved manifest carries %d bundle(s), not the one the build made", len(m.Bundles))
+	}
+	b := m.Bundles[0]
+	if b.Name != "tools" || b.Digest != bundleDigest || b.Language != "typescript" ||
+		b.Source != ArtifactStoreScheme+"nftables/tools/blobs/"+bundleDigest ||
+		len(b.Entrypoints) != 1 || b.Entrypoints[0] != "tools/index.js" {
+		t.Errorf("the bundle is carried as %+v", b)
+	}
+	// A repository manifest may not write what the build derives.
+	raw := `{"module":"x","version":"1","build":{"artifacts":[{"name":"t","kind":"bundle","language":"typescript"}]},` +
+		`"bundles":[{"name":"t","source":"s","digest":"` + bundleDigest + `"}]}`
+	if _, err := ParseManifest([]byte(raw)); err == nil || !strings.Contains(err.Error(), "bundles") {
+		t.Errorf("a manifest stating its build's output by hand was accepted: %v", err)
+	}
+}
+
+func TestEveryToolsBundleIsDeliveredWhereTheRuntimeRuns(t *testing.T) {
+	store := Rendering{ArtifactStore: "anchor.internal:5101",
+		Needed: map[string]map[string]string{RuntimeModule: {"broker": "sealed-credential"}}}
+	nftables := aToolsModule(t, "nftables", "tools/index.js")
+	zsh := aToolsModule(t, "zsh", "tools/index.js", "tools/more.js")
+
+	t.Run("with the runtime, one archive per tools bundle", func(t *testing.T) {
+		r := Resolution{Node: "anchor", Modules: []Manifest{nftables, zsh, theRuntime(t)}}
+		out, err := r.Declaration(store)
+		if err != nil {
+			t.Fatal(err)
+		}
+		archive := fileNamed(out, "nftables."+BundleID("tools"))
+		if archive == nil {
+			t.Fatalf("nftables' tools bundle was not delivered: %v", ids(out))
+		}
+		if archive["type"] != "archive" || archive["digest"] != bundleDigest ||
+			archive["path"] != BundleRoot+"/nftables/tools" {
+			t.Errorf("delivered as %v", archive)
+		}
+		if archive["source"] != "http://anchor.internal:5101/v2/nftables/tools/blobs/"+bundleDigest {
+			t.Errorf("fetched from %v, not through the store as this network reaches it", archive["source"])
+		}
+		if fileNamed(out, "zsh."+BundleID("tools")) == nil {
+			t.Errorf("zsh's tools bundle was not delivered: %v", ids(out))
+		}
+		// The runtime's own bundle is run, not loaded: its process delivers it, not an archive.
+		if fileNamed(out, RuntimeModule+"."+BundleID("runtime")) != nil {
+			t.Error("the runtime's own bundle was delivered as an archive beside its process")
+		}
+	})
+
+	t.Run("without the runtime, nothing changes", func(t *testing.T) {
+		r := Resolution{Node: "anchor", Modules: []Manifest{nftables, zsh}}
+		out, err := r.Declaration(store)
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, id := range ids(out) {
+			if strings.Contains(id, BundleID("")) {
+				t.Errorf("%s was delivered to a machine running no runtime to load it", id)
+			}
+		}
+	})
+}
+
+func ids(out []map[string]any) []string {
+	var names []string
+	for _, r := range out {
+		names = append(names, r["id"].(string))
+	}
+	return names
+}
+
+// One process per machine runs the runtime from its own bundle, told what it serves and from where,
+// where its credential is, and who the operator is — restarted when any of that changes.
+func TestTheMachineRunsOneRuntimeLoadingEveryDeliveredBundle(t *testing.T) {
+	with := Rendering{ArtifactStore: "anchor.internal:5101",
+		Needed: map[string]map[string]string{RuntimeModule: {"broker": "sealed-credential"}}}
+	nftables := aToolsModule(t, "nftables", "tools/index.js")
+	// A bundle carrying a daemon beside its tools says which files the runtime loads.
+	showcase := Manifest{Module: "showcase", Version: "1", Tools: []string{"greet"},
+		Build: &Build{Artifacts: []Artifact{{Name: "code", Kind: ArtifactBundle, Language: "typescript",
+			Entrypoints: []string{"daemon/index.js", "tools/index.js"}, Loads: []string{"tools/index.js"}}}}}
+	showcase, err := showcase.Resolve([]Built{{Name: "code", Kind: ArtifactBundle,
+		Reference: ArtifactStoreScheme + "showcase/code/blobs/" + bundleDigest, Digest: bundleDigest}})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r := Resolution{Node: "anchor", Account: "ops", Modules: []Manifest{nftables, showcase, theRuntime(t)}}
+	out, err := r.Declaration(with)
+	if err != nil {
+		t.Fatal(err)
+	}
+	process := fileNamed(out, RuntimeModule+"."+RuntimeProcessID())
+	if process == nil {
+		t.Fatalf("no runtime process was composed: %v", ids(out))
+	}
+	if process["type"] != "process" || process["name"] != RuntimeModule || process["digest"] != bundleDigest ||
+		process["source"] != "http://anchor.internal:5101/v2/"+RuntimeModule+"/runtime/blobs/"+bundleDigest {
+		t.Errorf("the runtime's process is %v", process)
+	}
+	if fmt.Sprint(process["run"]) != "[node src/main.js]" {
+		t.Errorf("the runtime is run as %v; its bundle's one entrypoint, by its language's interpreter", process["run"])
+	}
+	env := process["env"].(map[string]string)
+	if env[RuntimeToolModules] != "nftables="+BundleRoot+"/nftables/tools/tools/index.js,"+
+		"showcase="+BundleRoot+"/showcase/code/tools/index.js" {
+		t.Errorf("the runtime is told to serve %q: every loaded file, by module, and nothing a bundle runs", env[RuntimeToolModules])
+	}
+	if env[RuntimeBrokerFile] != "/var/lib/mesh/"+RuntimeModule+"/broker" {
+		t.Errorf("the runtime reads its credential at %q, not where the module's own secret is placed", env[RuntimeBrokerFile])
+	}
+	if env[RuntimeOperatorAccount] != "ops" || env[RuntimeOperatorHome] != "/home/ops" || process["user"] != "ops" {
+		t.Errorf("the operator is not handed to the runtime: %v as %v", env, process["user"])
+	}
+	restarts := fmt.Sprint(process["restart-on"])
+	for _, want := range []string{"nftables." + BundleID("tools"), "showcase." + BundleID("code"), RuntimeModule + "." + NeedID("broker")} {
+		if !strings.Contains(restarts, want) {
+			t.Errorf("the runtime is not restarted when %s changes: %s", want, restarts)
+		}
+	}
+	// After every bundle and the credential, so both exist before it starts.
+	names := ids(out)
+	if names[len(names)-1] != RuntimeModule+"."+RuntimeProcessID() {
+		t.Errorf("the runtime's process is not last: %v", names)
+	}
+
+	t.Run("a machine with no account runs it as root without the operator words", func(t *testing.T) {
+		out, err := Resolution{Node: "anchor", Modules: []Manifest{nftables, theRuntime(t)}}.Declaration(with)
+		if err != nil {
+			t.Fatal(err)
+		}
+		process := fileNamed(out, RuntimeModule+"."+RuntimeProcessID())
+		env := process["env"].(map[string]string)
+		if _, set := env[RuntimeOperatorAccount]; set {
+			t.Error("an operator account was named on a machine that has none")
+		}
+		if _, set := process["user"]; set {
+			t.Error("a user was set on a machine with no account")
+		}
+	})
+
+	t.Run("a runtime module built wrong is refused by name", func(t *testing.T) {
+		two := Manifest{Module: RuntimeModule, Version: "1", OwnSecrets: OwnSecrets{"broker": {Path: "/b"}},
+			Build: &Build{Artifacts: []Artifact{{Name: "runtime", Kind: ArtifactBundle, Language: "typescript",
+				Entrypoints: []string{"a.js", "b.js"}}}}}
+		resolved, err := two.Resolve([]Built{{Name: "runtime", Kind: ArtifactBundle,
+			Reference: ArtifactStoreScheme + "x/runtime/blobs/" + bundleDigest, Digest: bundleDigest}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		_, err = Resolution{Node: "anchor", Modules: []Manifest{resolved}}.Declaration(with)
+		if err == nil || !strings.Contains(err.Error(), "entrypoint") {
+			t.Errorf("a runtime bundle with two entrypoints was composed: %v", err)
+		}
+	})
+}

internal/catalogue/verbs.go

@@ -136,16 +136,6 @@ var ControllerVerbs = []Verb{
 			"node":   "the machine that runs the module",
 			"module": "the module's name",
 		}, []string{"node", "module"})},
-	{Name: "token", Description: "Issue a one-time token for a machine to join with. Give the public half of the " +
-		"tunnel key the machine made (`nox-mesh-host key`): the machine is given its address and made a peer of " +
-		"the hub, and joins through the tunnel. The token is shown once, in the answer.",
-		Input: schema(map[string]string{
-			"node":        "a machine the mesh already has a record for",
-			"new":         "or the name of a machine to create the record for",
-			"overlay_key": "the public half of the machine's tunnel key",
-			"for":         "how long it may be used, as a duration (default 1h)",
-			"adopted":     "\"true\" when the machine is in use and joins adopted",
-		}, nil)},
 	{Name: "settings", Description: "Set what an assignment is configured with: a module's settings for the whole mesh, " +
 		"or for one machine. Replaces that layer whole — what it does not name, it no longer sets — and takes effect " +
 		"at the next push. With clear, removes the layer and the module is back to what its definition says.",

internal/inventory/bususers.go

@@ -42,6 +42,9 @@ const (
 	BusModule     = "module"
 	BusEnrolment  = "enrolment"
 	BusPerson     = "person"
+	// BusNodeTools is a machine's tool runtime (novox/hq ADR 0175): named like the module it
+	// stands for, recorded as what it is.
+	BusNodeTools = "node-tools"
 )
 
 // MintBusPassword makes a bus password and records its hash under a username, replacing whatever was

internal/inventory/catalogue.go

@@ -42,6 +42,11 @@ type Source struct {
 	// Seen is when the source was last looked at — by a build, by hand, or by the forge saying it
 	// moved. What a late report of an older move is judged against.
 	Seen time.Time
+	// Against is every artifact the build this manifest came from stood on, as recorded. Part of a
+	// module's provenance like the commit is, and what tells a built manifest's base when the manifest
+	// itself no longer carries its build (novox/hq to-be 38 WP2.4). Empty for a manifest handed over
+	// by hand, which carries its `build.on` itself.
+	Against []string
 }
 
 // Current reports whether what the mesh holds is what the source last had.
@@ -61,6 +66,22 @@ func (s Source) Current() bool {
 // gains a requirement, a claim, a resource. What matters is that the change is visible the next
 // time a node is resolved, which it is.
 func (i *Inventory) RegisterModule(ctx context.Context, m catalogue.Manifest, from Source) error {
+	// **Once the node's tool runtime is in the catalogue, the pattern it retires is refused**
+	// (novox/hq ADR 0175, to-be 38 WP2.4): a module serving its tools from a container built on the
+	// runtime's image. Refused at registration, by name, because this is the mechanism that keeps
+	// the old pattern from returning by habit — a rebuild of an unmoved module stops here with the
+	// record that says why. Before the runtime exists the pattern is accepted as it always was.
+	if m.Module != catalogue.RuntimeModule {
+		if why := catalogue.ToolContainerOnTheRuntime(m, from.Against); why != "" {
+			runtime, err := i.hasModule(ctx, catalogue.RuntimeModule)
+			if err != nil {
+				return err
+			}
+			if runtime {
+				return fmt.Errorf("%s is not registered: %s", m.Module, why)
+			}
+		}
+	}
 	raw, err := json.Marshal(m)
 	if err != nil {
 		return err
@@ -89,6 +110,16 @@ func (i *Inventory) RegisterModule(ctx context.Context, m catalogue.Manifest, fr
 	return err
 }
 
+// hasModule is whether the catalogue holds a module of that name.
+func (i *Inventory) hasModule(ctx context.Context, name string) (bool, error) {
+	var one int
+	err := i.store.Pool().QueryRow(ctx, `select 1 from module where name = $1`, name).Scan(&one)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return false, nil
+	}
+	return err == nil, err
+}
+
 // SourceMoved records that a module's source has a newer commit than the mesh has built.
 //
 // This is the whole of noticing. Nothing here builds anything — it writes down that the two

internal/inventory/catalogue_test.go

@@ -685,3 +685,32 @@ func TestRegisteringWithoutProvenanceKeepsTheSeat(t *testing.T) {
 		t.Fatalf("a hand-registered manifest erased where the module comes from: %+v", got)
 	}
 }
+
+// Once the node's tool runtime is in the catalogue, a module serving its tools from a container
+// built on the runtime's image is refused at registration, naming the record (novox/hq ADR 0175,
+// to-be 38 WP2.4). Before, it is accepted as it always was — so a mesh converts in the order the
+// design says and nothing is refused before there is anything to move to.
+func TestAToolContainerIsRefusedOnceTheRuntimeIsRegistered(t *testing.T) {
+	inv := fresh(t)
+	filter := catalogue.Manifest{Module: "nftables", Version: "1", Tools: []string{"firewall_rules"},
+		Resources: []map[string]any{{"id": "runtime", "type": "container", "name": "mesh-nftables"}}}
+	stoodOn := []string{catalogue.ArtifactStoreScheme + "mesh-tools/runtime@sha256:" + strings.Repeat("d", 64)}
+
+	if err := inv.RegisterModule(t.Context(), filter, Source{Repository: "/r", Against: stoodOn}); err != nil {
+		t.Fatalf("before the runtime exists the old pattern is accepted: %v", err)
+	}
+	runtime := catalogue.Manifest{Module: catalogue.RuntimeModule, Version: "1"}
+	if err := inv.RegisterModule(t.Context(), runtime, Source{Repository: "/r"}); err != nil {
+		t.Fatal(err)
+	}
+	err := inv.RegisterModule(t.Context(), filter, Source{Repository: "/r", Against: stoodOn})
+	if err == nil || !strings.Contains(err.Error(), "ADR 0175") {
+		t.Fatalf("the old pattern was registered beside the runtime: %v", err)
+	}
+	// A module that moved its tools to a bundle registers.
+	moved := filter
+	moved.Resources = nil
+	if err := inv.RegisterModule(t.Context(), moved, Source{Repository: "/r", Against: stoodOn}); err != nil {
+		t.Fatalf("a module whose tools are a bundle was refused: %v", err)
+	}
+}

internal/inventory/migrations/0055-a-token-is-issued-for-a-tunnel-key.sql

@@ -1,7 +0,0 @@
--- A token issued for a tunnel key (novox/hq ADR 0169).
---
--- A machine that joins through the tunnel makes its key first, and the token is issued for it: the
--- hub is told the key before the token is shown. So enrolment must take that key and no other — a
--- different one is a machine the hub does not know, offering a tunnel that would never answer. Null
--- for a token issued without one, which enrols as before.
-alter table enrolment_token add column overlay_key text;

internal/inventory/nodes.go

@@ -356,33 +356,6 @@ func (i *Inventory) Claim(ctx context.Context, secret, by string, again bool) (N
 	return scanNode(i.store.Pool().QueryRow(ctx, `select `+nodeColumns+` from node where id = $1`, id))
 }
 
-// BindTokenToKey records the tunnel key a node's live token was issued for (novox/hq ADR 0169), so
-// enrolment takes that key and no other. Refused when the node has no live token to bind: a key
-// recorded against nothing would be a promise nothing keeps.
-func (i *Inventory) BindTokenToKey(ctx context.Context, node, key string) error {
-	tag, err := i.store.Pool().Exec(ctx,
-		`update enrolment_token set overlay_key = $2
-		  where node = $1 and redeemed is null and expires > now()`, node, key)
-	if err != nil {
-		return err
-	}
-	if tag.RowsAffected() == 0 {
-		return fmt.Errorf("no live token to issue for the tunnel key")
-	}
-	return nil
-}
-
-// TokenKey is the tunnel key a token was issued for, or empty when it was issued without one.
-func (i *Inventory) TokenKey(ctx context.Context, secret string) (string, error) {
-	var key *string
-	err := i.store.Pool().QueryRow(ctx,
-		`select overlay_key from enrolment_token where secret = $1`, hashSecret(secret)).Scan(&key)
-	if err != nil || key == nil {
-		return "", err
-	}
-	return *key, nil
-}
-
 // Spend makes a claimed token used, only for the presenter holding the claim. The last write to the
 // store in an enrolment, so a token is spent exactly when the node it enrolled is complete. Spent
 // again by the same presenter is not an error: an answer lost after the first spend.

internal/link/bus_nats.go

@@ -12,7 +12,6 @@ func ConnectNats(js *broker.JetStream, enroller Enroller, listener Listener) *Se
 		inbound:  Nats(js),
 		bus:      OverNATS{JS: js.Context(), Conn: js.Conn()},
 		js:       js,
-		consumers: js,
 		enroller: enroller,
 		listener: listener,
 		log:      newLog(),

internal/link/enrol_consumer_test.go

@@ -1,51 +0,0 @@
-package link
-
-import (
-	"context"
-	"encoding/json"
-	"io"
-	"log"
-	"testing"
-	"time"
-
-	"github.com/novox/mesh-controller/internal/broker"
-)
-
-type ensured struct{ consumers []broker.Consumer }
-
-func (e *ensured) EnsureConsumer(c broker.Consumer) error {
-	e.consumers = append(e.consumers, c)
-	return nil
-}
-
-type acceptsAs string
-
-func (n acceptsAs) Enrol(context.Context, EnrolRequest) (EnrolReply, error) {
-	return EnrolReply{Accepted: true, Node: string(n)}, nil
-}
-
-type anEnrolment struct{ body []byte }
-
-func (m anEnrolment) Kind() string                         { return "enrol" }
-func (m anEnrolment) Body() []byte                         { return m.body }
-func (m anEnrolment) Redelivered() bool                    { return false }
-func (m anEnrolment) HeldFor() time.Duration               { return 0 }
-func (m anEnrolment) Answer(context.Context, []byte) error { return nil }
-func (m anEnrolment) Took() error                          { return nil }
-func (m anEnrolment) Hold(time.Duration) error             { return nil }
-func (m anEnrolment) Drop() error                          { return nil }
-
-// **A node that enrols can hear its declarations at once** (novox/hq 04-ISSUES/146): its consumer is
-// made as it enrols, not only when the control plane next starts — the first machine of a mesh
-// enrols after the control plane is up, and heard nothing.
-func TestAnEnrolledNodeIsGivenHowItHearsItsDeclarations(t *testing.T) {
-	made := &ensured{}
-	s := &Server{enroller: acceptsAs("anchor"), consumers: made, log: log.New(io.Discard, "", 0)}
-	body, _ := json.Marshal(EnrolRequest{Node: "anchor"})
-	s.enrolling(context.Background(), anEnrolment{body: body})
-
-	want := broker.NodeConsumer("anchor")
-	if len(made.consumers) != 1 || made.consumers[0].Name != want.Name || made.consumers[0].Stream != want.Stream {
-		t.Fatalf("the enrolled node was given %v, want its own declaration consumer %v", made.consumers, want)
-	}
-}

internal/link/enrol_tunnel_key_test.go

@@ -1,37 +0,0 @@
-package link_test
-
-import (
-	"context"
-	"strings"
-	"testing"
-
-	"github.com/novox/mesh-controller/internal/link"
-)
-
-// **A token issued for a tunnel key takes that key and no other** (novox/hq ADR 0169). The hub was
-// sent the key before the token was shown, so another key is a machine it does not know.
-func TestATokenIssuedForATunnelKeyTakesThatKeyAndNoOther(t *testing.T) {
-	inv, ident := aMeshReadyToEnrol(t)
-	ctx := context.Background()
-	secret, public := aTokenFor(t, inv, "joiner")
-	node, err := inv.NodeByName(ctx, "joiner")
-	if err != nil {
-		t.Fatal(err)
-	}
-	const issuedFor = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
-	if err := inv.BindTokenToKey(ctx, node.ID, issuedFor); err != nil {
-		t.Fatal(err)
-	}
-	e := link.Enrolment{Inventory: inv, Identity: ident}
-
-	_, err = e.Enrol(ctx, link.EnrolRequest{Node: "joiner", Secret: secret, PublicKey: public,
-		OverlayKey: "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB="})
-	if err == nil || !strings.Contains(err.Error(), "issued for the tunnel key") {
-		t.Fatalf("a token issued for one key took another: %v", err)
-	}
-
-	if _, err := e.Enrol(ctx, link.EnrolRequest{Node: "joiner", Secret: secret, PublicKey: public,
-		OverlayKey: issuedFor}); err != nil {
-		t.Fatalf("the key the token was issued for was refused: %v", err)
-	}
-}

internal/link/enrolment.go

@@ -86,18 +86,6 @@ func (e Enrolment) Enrol(ctx context.Context, request EnrolRequest) (reply Enrol
 	if err != nil {
 		return EnrolReply{}, err
 	}
-	// **A token issued for a tunnel key takes that key and no other** (novox/hq ADR 0169). The hub
-	// was told it before the token was shown; another key is a machine the hub does not know.
-	// Checked before anything is recorded, so a refusal changes nothing.
-	bound, err := e.Inventory.TokenKey(ctx, secret)
-	if err != nil {
-		return EnrolReply{}, err
-	}
-	if bound != "" && request.OverlayKey != bound {
-		return EnrolReply{}, fmt.Errorf("%s's token was issued for the tunnel key %s and the machine "+
-			"offered %q — the key it made with `nox-mesh-host key` is the one to issue for",
-			node.Name, bound, request.OverlayKey)
-	}
 
 	if _, err := e.Identity.RecordNodeKey(ctx, node.ID, public); err != nil {
 		return EnrolReply{}, fmt.Errorf("%s's key could not be recorded: %w", node.Name, err)

internal/link/serve.go

@@ -73,8 +73,6 @@ type Server struct {
 	inbound Inbound
 	bus     Bus
 	js      *broker.JetStream
-	// consumers makes a node's declaration consumer as it enrols; the bus connection, or a stand-in.
-	consumers interface{ EnsureConsumer(broker.Consumer) error }
 
 	enroller Enroller
 	listener Listener
@@ -385,7 +383,6 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 		default:
 			reply = accepted
 			s.log.Printf("enrolled %s", accepted.Node)
-			s.hearsItsDeclarations(accepted.Node)
 		}
 	}
 
@@ -405,24 +402,6 @@ func (s *Server) enrolling(ctx context.Context, m Control) {
 	_ = m.Took()
 }
 
-// hearsItsDeclarations makes the consumer a node reads its declarations through, as it enrols and
-// before it is answered.
-//
-// **Created at enrolment, as the consumer's own doc has always said** (novox/hq 04-ISSUES/146). It
-// was asserted only when the control plane started, so the first machine of a mesh — which enrols
-// after the control plane is already up — joined and then heard nothing, its host retrying "consumer
-// not found" for ever. Failing here is said and does not unspend the token: the next start of the
-// control plane asserts it again.
-func (s *Server) hearsItsDeclarations(node string) {
-	if s.consumers == nil {
-		return
-	}
-	if err := s.consumers.EnsureConsumer(broker.NodeConsumer(node)); err != nil {
-		s.log.Printf("%s enrolled, and how it hears its declarations could not be made — it will hear "+
-			"nothing until the control plane next starts: %v", node, err)
-	}
-}
-
 // wasBuilt keeps what a builder said, whichever way it went.
 //
 // This is for results nobody was waiting for. A build asked for with `build` is answered directly

internal/token/token.go

@@ -55,26 +55,6 @@ type Token struct {
 	// that it speaks the firewall found on the machine, because an adopted node keeps that firewall
 	// in force. Absent for a converged node, so a converged token is byte for byte what it was.
 	Adopted bool `json:"adopted,omitempty"`
-
-	// Tunnel is the one peer a joining machine needs, when the token was issued for its tunnel key
-	// (novox/hq ADR 0169). The machine brings its tunnel up from this alone and reaches the bus over
-	// it, at an address on the private network — so the bus is never open to the internet. Absent
-	// on a token issued without a key, which then reads byte for byte as before.
-	Tunnel *Tunnel `json:"tunnel,omitempty"`
-}
-
-// Tunnel is the joining machine's side of its first tunnel: its own address and the hub to reach.
-type Tunnel struct {
-	// Key is the public half of the key the machine made itself, which this token was issued for.
-	// The private half never left the machine (novox/hq ADR 0004).
-	Key string `json:"key"`
-	// Address is the machine's own address on the private network, with its prefix.
-	Address string `json:"address"`
-	// Range is the private network, routed through the hub until the machine is told more.
-	Range string `json:"range"`
-	// HubKey and HubEndpoint are the hub's tunnel key and where it is dialled.
-	HubKey      string `json:"hub_key"`
-	HubEndpoint string `json:"hub_endpoint"`
 }
 
 // Missing names the parts that are not filled in.
@@ -103,19 +83,6 @@ func (t Token) Missing() []string {
 	if strings.TrimSpace(t.Secret) == "" {
 		missing = append(missing, "the one-time secret — nothing to present")
 	}
-	if t.Tunnel != nil {
-		for _, part := range []struct{ value, says string }{
-			{t.Tunnel.Key, "the machine's own tunnel key — the hub would not know it"},
-			{t.Tunnel.Address, "the machine's address on the private network"},
-			{t.Tunnel.Range, "the private network's range — nothing to route through the hub"},
-			{t.Tunnel.HubKey, "the hub's tunnel key — nothing to dial"},
-			{t.Tunnel.HubEndpoint, "where the hub's tunnel is dialled"},
-		} {
-			if strings.TrimSpace(part.value) == "" {
-				missing = append(missing, part.says)
-			}
-		}
-	}
 	return missing
 }
 

internal/token/token_test.go

@@ -172,38 +172,3 @@ func TestATokenWithNoNameIsRefused(t *testing.T) {
 		t.Fatalf("the refusal does not say what is missing: %v", without.Missing())
 	}
 }
-
-// A token issued for a tunnel key carries the one peer a joining machine needs (novox/hq ADR 0169),
-// and says which part is missing rather than producing a tunnel that never answers.
-func TestATokenThroughTheTunnelCarriesThePeerOrSaysWhatIsMissing(t *testing.T) {
-	whole := Token{Node: "n", Broker: "10.42.0.1:4222", Fingerprint: "sha256:x", Signer: make([]byte, 32), Secret: "s",
-		Tunnel: &Tunnel{Key: "k", Address: "10.42.0.9/32", Range: "10.42.0.0/16", HubKey: "h", HubEndpoint: "198.51.100.1:51820"}}
-	if !whole.Complete() {
-		t.Fatalf("a whole token through the tunnel reads as missing %v", whole.Missing())
-	}
-	encoded, err := whole.Encode()
-	if err != nil {
-		t.Fatal(err)
-	}
-	back, err := Decode(encoded)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if back.Tunnel == nil || *back.Tunnel != *whole.Tunnel {
-		t.Fatalf("the tunnel did not survive the round trip: %+v", back.Tunnel)
-	}
-
-	part := whole
-	part.Tunnel = &Tunnel{Key: "k", Address: "10.42.0.9/32"}
-	if len(part.Missing()) != 3 {
-		t.Errorf("a tunnel without the hub and the range should name three missing parts: %v", part.Missing())
-	}
-
-	// And a token issued without a key carries no tunnel at all, byte for byte as before.
-	plain := whole
-	plain.Tunnel = nil
-	raw, _ := plain.Encode()
-	if strings.Contains(raw, "tunnel") {
-		t.Error("a token without a key mentions a tunnel")
-	}
-}