diff --git a/modules/mesh-grants/cmd/mesh-grants/integration_test.go b/modules/mesh-grants/cmd/mesh-grants/integration_test.go
index b60896a0..6d72de3c 100644
--- a/modules/mesh-grants/cmd/mesh-grants/integration_test.go
+++ b/modules/mesh-grants/cmd/mesh-grants/integration_test.go
@@ -189,6 +189,22 @@ func TestTheGrantsPartWhole(t *testing.T) {
 		}
 		t.Cleanup(func() { _ = osub.Unsubscribe() })
 	}
+	// D-30 (novox/hq ADR 0636 §1): the seat mesh-catalog's holder answers the seat list with no trunk seat named, so the reader
+	// has heard the seat and holds the bootstrapped definitions, and every module is composed. (The unit case holds a module
+	// while the list is unread.)
+	var seatAnswering atomic.Bool
+	seatAnswering.Store(true)
+	for _, subject := range []string{"mesh.seat.mesh-catalog.call.seat-definitions", "mesh.seat.mesh-catalog.call.seat-definitions.>"} {
+		if _, err := nc.Subscribe(subject, func(m *nats.Msg) {
+			if !seatAnswering.Load() {
+				_ = m.Respond([]byte(`{"error":"not connected yet","node":"a"}`))
+				return
+			}
+			answer(m, map[string]any{"revision": 1, "seats": []any{}})
+		}); err != nil {
+			t.Fatal(err)
+		}
+	}
 	// A membership is never said on its subject any more (issue 1126).
 	var said atomic.Int32
 	if _, err := nc.Subscribe("mesh.assignment.>", func(*nats.Msg) { said.Add(1) }); err != nil {
diff --git a/modules/mesh-grants/cmd/mesh-grants/main.go b/modules/mesh-grants/cmd/mesh-grants/main.go
index 012ac6cb..e1cd993f 100644
--- a/modules/mesh-grants/cmd/mesh-grants/main.go
+++ b/modules/mesh-grants/cmd/mesh-grants/main.go
@@ -36,6 +36,7 @@ import (
 	stdio "git.novox.be/novox/mesh-sdk/go"
 	"git.novox.be/novox/mesh-sdk/go/announce"
 	"git.novox.be/novox/mesh-sdk/go/process"
+	"git.novox.be/novox/mesh-sdk/go/seatlist"
 
 	"git.novox.be/novox/mesh-sdk/go/views"
 
@@ -107,6 +108,11 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		return err
 	}
 	bus := newBusReader(ctx, js)
+	// The module has one durable consumer of EVENTS: one hub pulls it and hands each message to the part that hears it (the
+	// owners' views events, the seat mesh-catalog's verdicts and seat list events, the other seats' events the follower hears),
+	// started once all are registered.
+	hub := process.NewEventHub(logger.Printf)
+	defer hub.Stop()
 	// The owners' five states by their first views (ADR 0615, ADR 0622): asked through the part's own account, then
 	// followed on the owners' views families, which the hearing below hands them.
 	sayCond := sayVia(ctx, js, account.Module)
@@ -124,6 +130,10 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		Objects: sealedObjects{ctx: ctx, js: js}, Logf: logger.Printf,
 		Bus: grants.BusAddress{URL: account.URL, Fingerprint: account.Fingerprint}}
 	f.Watch = fv
+	// The seat list: read over the connection and the hub, given to catalogue at every change, and a pass composes again then.
+	gate := &seatGate{}
+	gate.follow(seatlist.ProcessBus(conn.Call, hub), f.Wake, logger.Printf)
+	f.Part.SeatList = gate
 	f.Part.Say = sayCond
 	fv.Start(ctx, f.Wake)
 	f.Asked = func(wake func()) error {
@@ -142,11 +152,6 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// dropped carry the bindings: ADR 0595 §1, §7), each on the durable consumer its own membership names; one not
 	// there yet is opened at the next change, and one opened is never opened twice.
 	opened := map[string]bool{}
-	// The module has one durable consumer of EVENTS: one hub pulls it and hands each message to the part that hears it
-	// (the owners' views events, the seat mesh-catalog's verdicts, the other seats' events the follower hears), started
-	// once all are registered.
-	hub := process.NewEventHub(logger.Printf)
-	defer hub.Stop()
 	registered := false
 	f.Hear = func(handle func(string, []byte)) error {
 		if !registered {
diff --git a/modules/mesh-grants/cmd/mesh-grants/seatlist.go b/modules/mesh-grants/cmd/mesh-grants/seatlist.go
new file mode 100644
index 00000000..3c477fb2
--- /dev/null
+++ b/modules/mesh-grants/cmd/mesh-grants/seatlist.go
@@ -0,0 +1,67 @@
+package main
+
+import (
+	"errors"
+	"mesh-grants/internal/grants"
+	"sync/atomic"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/seatlist"
+)
+
+// The grants part composes from the seat list it reads (novox/hq ADR 0635 §1, ADR 0636 §1, D-30): through the seat
+// mesh-catalog's verb seat-definitions and its two events, from the bootstrapped definitions until the seat has answered. What
+// the reader holds is given to catalogue at every change, which composes every membership and grant, and a module that names a
+// seat the list does not yet is held back, as a manifest waiting for a judge is, and what runs is composed from its running
+// build's manifest. The process reads over its connection and the event hub; the tools' bundle over the runtime.
+
+// seatListTools are the reader's two tools (ADR 0636 §7): every operator's session and the healers may read again.
+var seatListAgainCallers = []string{stdio.AnyPerson, "mesh-healers"}
+
+// seatGate is the reader the part gates by, set once it is started; before, it acts on nothing new.
+type seatGate struct {
+	reader atomic.Pointer[seatlist.Reader]
+}
+
+func (g *seatGate) MayAct(seats ...string) bool {
+	r := g.reader.Load()
+	return r != nil && r.MayAct(seats...)
+}
+
+// follow starts the reader over bus: what it holds is given to catalogue at once and at every change, and changed is called
+// then (a pass composes again).
+func (g *seatGate) follow(bus seatlist.Bus, changed func(), logf func(string, ...any)) *seatlist.Reader {
+	reader, err := seatlist.Start(seatlist.Config{Bus: bus, Bootstrap: seatlist.Bootstrapped(),
+		OnChange: func(seats []catalogue.Seat) {
+			catalogue.UseSeats(seats)
+			if changed != nil {
+				changed()
+			}
+		}})
+	if err != nil {
+		logf("the grants part cannot follow its seat list, so it composes only the modules the bootstrapped seats name: %v", err)
+	}
+	if reader != nil {
+		catalogue.UseSeats(reader.Seats())
+		g.reader.Store(reader)
+	}
+	return reader
+}
+
+// tools are the two tools over whatever reader the gate holds at the call.
+func (g *seatGate) tools() []stdio.Tool {
+	names := []string{grants.ToolSeatList, grants.ToolSeatListAgain}
+	shape := seatlist.Tools(&seatlist.Reader{}, names[0], names[1], seatListAgainCallers)
+	for i := range shape {
+		run := i
+		shape[i].Run = func(args map[string]any) (any, error) {
+			r := g.reader.Load()
+			if r == nil {
+				return nil, errors.New("the seat list reader has not started yet: the runtime has not served this module")
+			}
+			return seatlist.Tools(r, names[0], names[1], seatListAgainCallers)[run].Run(args)
+		}
+	}
+	return shape
+}
diff --git a/modules/mesh-grants/cmd/mesh-grants/tools.go b/modules/mesh-grants/cmd/mesh-grants/tools.go
index dc973aad..9c0f81db 100644
--- a/modules/mesh-grants/cmd/mesh-grants/tools.go
+++ b/modules/mesh-grants/cmd/mesh-grants/tools.go
@@ -5,11 +5,13 @@ import (
 	"encoding/json"
 	"fmt"
 	"maps"
+	"os"
 	"sort"
 	"strings"
 	"sync"
 	"time"
 
+	"git.novox.be/novox/mesh-sdk/go/seatlist"
 	"git.novox.be/novox/mesh-sdk/go/views"
 
 	"git.novox.be/novox/mesh-contracts/health-and-repair/go/clients/meshhandactsclient"
@@ -254,8 +256,14 @@ func recordHandAct(what, why string) error {
 // serveTools serves the tools to the runtime until it stops.
 func serveTools() error {
 	tv := &toolViews{}
-	p := &grants.Part{Read: runtimeReader{views: tv}, Call: runtimeBus{}, Store: runtimeStore{}, Emit: runtimeBus{}}
-	tools := toolsOf(p)
+	gate := &seatGate{}
+	p := &grants.Part{Read: runtimeReader{views: tv}, Call: runtimeBus{}, Store: runtimeStore{}, Emit: runtimeBus{}, SeatList: gate}
+	// The reader asks through the runtime, which serves once Serve has its channel.
+	go func() {
+		<-stdio.Served()
+		gate.follow(seatlist.StdioBus(), nil, func(f string, a ...any) { fmt.Fprintf(os.Stderr, "mesh-grants: "+f+"\n", a...) })
+	}()
+	tools := append(toolsOf(p), gate.tools()...)
 	for i := range tools {
 		run := tools[i].Run
 		tools[i].Run = func(a map[string]any) (any, error) { tv.fresh(); return run(a) }
diff --git a/modules/mesh-grants/grants_test.go b/modules/mesh-grants/grants_test.go
index 69ea7ee3..f54ed06e 100644
--- a/modules/mesh-grants/grants_test.go
+++ b/modules/mesh-grants/grants_test.go
@@ -2231,6 +2231,31 @@ func TestGrants(t *testing.T) {
 		}
 	})
 
+	// D-30 (novox/hq ADR 0636 §1): until the seat list has been read, a module whose seats are not all bootstrapped ones is held back
+	// as a manifest waiting for a judge is, named `manifest of <module>: it waits for the seat list`, and composed once the
+	// list names its seats; the bus module, which claims a bootstrapped seat, is composed throughout.
+	t.Run("the seat list unread holds a module whose seats are not bootstrapped", func(t *testing.T) {
+		b := fixture()
+		p := partOn(b)
+		gate := &seatGate{bootstrapped: []string{"mesh-broker"}}
+		p.SeatList = gate
+		p.Compose()
+		refused := strings.Join(p.Last().Refused, "\n")
+		for _, module := range []string{"mod-x", "mod-y"} {
+			if !strings.Contains(refused, "manifest of "+module+": it waits for the seat list") {
+				t.Errorf("%s is not held while the seat list is unread: %v", module, p.Last().Refused)
+			}
+		}
+		if strings.Contains(refused, "manifest of nats") {
+			t.Errorf("the bus module claims a bootstrapped seat and is held: %v", p.Last().Refused)
+		}
+		gate.read = true
+		p.Compose()
+		if r := p.Last().Refused; len(r) != 0 {
+			t.Errorf("held after the seat list was read: %v", r)
+		}
+	})
+
 	// DLV-G1, 1966/AC32-AC33 (novox/hq ADR 0595 §1, §7; design 25 § 12.2): the bus module's created writes the binding into
 	// the module's membership on every machine it is assigned, one assigned later included; recreated rewrites it; dropped
 	// removes it; before created, on a refused, or from an emitter holding no mesh-broker, none.
@@ -3280,3 +3305,25 @@ func waitFor(t *testing.T, ok func() bool) {
 	}
 	t.Fatal("never came")
 }
+
+// seatGate is a seat list reader as a test gives it: unread, it lets a module act whose seats are all bootstrapped ones (and
+// at least one); read, any.
+type seatGate struct {
+	bootstrapped []string
+	read         bool
+}
+
+func (g *seatGate) MayAct(seats ...string) bool {
+	if g.read {
+		return true
+	}
+	if len(seats) == 0 {
+		return false
+	}
+	for _, s := range seats {
+		if !slices.Contains(g.bootstrapped, s) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/modules/mesh-grants/internal/grants/consumers.go b/modules/mesh-grants/internal/grants/consumers.go
index b77fae66..48bbd2ce 100644
--- a/modules/mesh-grants/internal/grants/consumers.go
+++ b/modules/mesh-grants/internal/grants/consumers.go
@@ -200,7 +200,7 @@ func (p *Part) MatchConsumer(stream, name string) (any, error) {
 	if stream == "" || name == "" {
 		return nil, errors.New("consumer-match names a stream and a consumer")
 	}
-	in := ReadInputs(p.Read, &p.cache)
+	in := p.inputs()
 	recs, _ := Records(in)
 	users, err := buscompose.Users(recs)
 	if err != nil {
diff --git a/modules/mesh-grants/internal/grants/inputs.go b/modules/mesh-grants/internal/grants/inputs.go
index 0b330afa..49afd3f6 100644
--- a/modules/mesh-grants/internal/grants/inputs.go
+++ b/modules/mesh-grants/internal/grants/inputs.go
@@ -61,7 +61,10 @@ const (
 )
 
 // Invokes is every tool the part calls.
-var Invokes = append([]string{CallUsers, CallUserCan, CallStreams, CallRootFree, CallHandAct}, firstViewTools()...)
+var Invokes = append([]string{CallUsers, CallUserCan, CallStreams, CallRootFree, CallHandAct, CallSeatDefinitions}, firstViewTools()...)
+
+// CallSeatDefinitions reads the seat list (mesh-sdk seatlist): the verb of the seat mesh-catalog.
+const CallSeatDefinitions = "seat:mesh-catalog.seat-definitions"
 
 // CallHandAct records a person's act (grants_first_view_again).
 const CallHandAct = "seat:mesh-hand-acts.hand-act"
@@ -204,6 +207,30 @@ const BusModule = "nats"
 type Manifests struct {
 	mu     sync.Mutex
 	parsed map[string]catalogue.Manifest
+	// gate says whether a manifest naming some seats may be composed yet (the seat list reader, ADR 0636 §1); nil gates none.
+	gate SeatGate
+}
+
+// SeatGate is what the part asks of the seat list reader before it composes a module new to it: whether a module that
+// claims or invokes the given seats may be acted on (seatlist.Reader.MayAct). Until the seat list has been read only a module
+// whose seats are all bootstrapped ones may; the rest is held as a manifest waiting for a judge is, its running build's
+// manifest composing what runs, so nothing that runs is stopped (held.go).
+type SeatGate interface {
+	MayAct(seats ...string) bool
+}
+
+// SeatsOf are the seats a manifest claims or invokes, which the seat list must name before the part composes the module.
+func SeatsOf(m catalogue.Manifest) []string {
+	var seats []string
+	for _, c := range m.Claims {
+		seats = append(seats, c.Name)
+	}
+	for _, in := range m.Invokes {
+		if seat, _, ok := catalogue.SeatInvoke(in); ok {
+			seats = append(seats, seat)
+		}
+	}
+	return seats
 }
 
 func (c *Manifests) get(r Reader, digest string) (catalogue.Manifest, error) {
@@ -263,6 +290,9 @@ func each(r Reader, state string, gaps *[]Gap) map[string][]byte {
 
 // ReadInputs reads what the shadow composes from. It never fails: what it cannot read is a gap.
 func ReadInputs(r Reader, cache *Manifests) Inputs {
+	cache.mu.Lock()
+	gate := cache.gate
+	cache.mu.Unlock()
 	in := Inputs{Assigned: map[string][]string{}, Manifests: map[string]catalogue.Manifest{}, Digests: map[string]string{}, Fingerprints: map[string]string{},
 		NoFingerprint: map[string]string{}, Running: map[string]catalogue.Manifest{},
 		Values: map[string]any{}, Gaps: append([]Gap(nil), standingGaps...)}
@@ -392,6 +422,9 @@ func ReadInputs(r Reader, cache *Manifests) Inputs {
 		if err == nil {
 			m, err = cache.get(r, v.Manifest)
 		}
+		if err == nil && gate != nil && !gate.MayAct(SeatsOf(m)...) {
+			err = errors.New("it waits for the seat list: the list has not been read yet and the manifest names seats the bootstrapped list does not (novox/hq ADR 0636 §1)")
+		}
 		if err != nil {
 			// Every manifest, assigned or not: one refused declares no seat, so its holders compose as placed nowhere.
 			g := Gap{Input: "manifest of " + module, Why: err.Error()}
diff --git a/modules/mesh-grants/internal/grants/part.go b/modules/mesh-grants/internal/grants/part.go
index a23ab3b0..7fe5eb05 100644
--- a/modules/mesh-grants/internal/grants/part.go
+++ b/modules/mesh-grants/internal/grants/part.go
@@ -162,6 +162,9 @@ type Part struct {
 	// Say says a condition to the operator: the process's; nil in the tools.
 	Say func(oc.Condition) error
 	Now func() time.Time
+	// SeatList is the seat list reader, which gates a module whose seats the list has not named (inputs.go, SeatGate); nil
+	// gates none.
+	SeatList SeatGate
 
 	cache Manifests
 	mu    sync.Mutex
@@ -279,7 +282,7 @@ func (p *Part) Compose() Result {
 	}()
 	// A first view's condition the condition keeper did not take is said again at every pass until it lands.
 	p.Views.SayUnsaid()
-	in := ReadInputs(p.Read, &p.cache)
+	in := p.inputs()
 	p.keepBrokers(in)
 	if bound, err := p.boundStreams(); err != nil {
 		res.Errors = append(res.Errors, err.Error())
@@ -542,3 +545,11 @@ func names(us []User) []string {
 	}
 	return out
 }
+
+// inputs reads what the part composes from, a module whose seats the seat list has not named held back (SeatGate).
+func (p *Part) inputs() Inputs {
+	p.cache.mu.Lock()
+	p.cache.gate = p.SeatList
+	p.cache.mu.Unlock()
+	return ReadInputs(p.Read, &p.cache)
+}
diff --git a/modules/mesh-grants/internal/grants/rootfree.go b/modules/mesh-grants/internal/grants/rootfree.go
index a270dcc0..83bc8626 100644
--- a/modules/mesh-grants/internal/grants/rootfree.go
+++ b/modules/mesh-grants/internal/grants/rootfree.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"git.novox.be/novox/mesh-contracts/go/seats/meshbroker"
+	"git.novox.be/novox/mesh-delivery/contracts/go/seats/meshcatalog"
 	"slices"
 	"sort"
 	"strings"
@@ -42,7 +43,11 @@ const EventAccountIssued = "mesh-vault." + buscompose.AccountIssuedEvent
 // Consumes is every event the part hears, as its manifest's consumes name them.
 // The seat mesh-broker's created, recreated and dropped are heard as every seat's event, `<seat>.<event>` on EVENTS (the
 // lead's ruling, registry milestone 13:0x), never on the bus module's own stream.
-var Consumes = append(slices.Clone(seatEvents), viewsEvents()...)
+var Consumes = append(append(slices.Clone(seatEvents), seatListEvents...), viewsEvents()...)
+
+// seatListEvents are the two events of the seat mesh-catalog the seat list reader follows (mesh-sdk seatlist), heard by it on the
+// module's event hub, so no handler of the hub takes them besides.
+var seatListEvents = []string{meshcatalog.Seat + "." + meshcatalog.EventSeatDefinitionChanged, meshcatalog.Seat + "." + meshcatalog.EventSeatDefinitionRemoved}
 
 // seatEvents are the events of seats the part follows its passes by, as `<seat>.<event>`.
 var seatEvents = []string{EventKeeperRaised, EventKeeperCleared, EventAccountIssued, meshbroker.Seat + "." + BrokerCreated,
diff --git a/modules/mesh-grants/internal/grants/tools.go b/modules/mesh-grants/internal/grants/tools.go
index a94e32d8..247d4081 100644
--- a/modules/mesh-grants/internal/grants/tools.go
+++ b/modules/mesh-grants/internal/grants/tools.go
@@ -26,11 +26,14 @@ const (
 	// ToolFirstViews and ToolFirstViewAgain read and ask again the part's first views (firstviews.go).
 	ToolFirstViews     = "grants_first_views"
 	ToolFirstViewAgain = "grants_first_view_again"
+	// ToolSeatList and ToolSeatListAgain read and read again the seat list the part composes from (mesh-sdk seatlist.Tools).
+	ToolSeatList      = "grants_seat_list"
+	ToolSeatListAgain = "grants_seat_list_again"
 )
 
 // Tools is every tool, in the manifest's order.
 var Tools = []string{ToolGrants, ToolMembership, ToolUserList, ToolComposeNow, ToolAssert, ToolAccounts, ToolConsumerMatch,
-	ToolAcceptHashes, ToolFirstViews, ToolFirstViewAgain}
+	ToolAcceptHashes, ToolFirstViews, ToolFirstViewAgain, ToolSeatList, ToolSeatListAgain}
 
 // WritesGrants is what grants says of the part's own grants: written once the list the bus loaded carries a build's
 // accounts, and the one key the assigner reads (ADR 0571 clause 9, which changes ADR 0547 clause 5).
@@ -105,7 +108,7 @@ func (p *Part) MembershipOf(node, module string) (any, error) {
 	if node == "" || module == "" {
 		return nil, errors.New("membership names a node and a module, or neither for every membership held back")
 	}
-	in := ReadInputs(p.Read, &p.cache)
+	in := p.inputs()
 	recs, left := Records(in)
 	notFree := WithRootFree(&recs, p.Call)
 	m, ok := Memberships(recs)[node+"."+module]
@@ -277,7 +280,7 @@ func (p *Part) AssertOne(module string) (any, error) {
 	held, heldErr := HeldStreams(p.Call)
 	var nodes []string
 	if module == buscompose.EngineModule {
-		nodes = ReadInputs(p.Read, &p.cache).Nodes // every node's bucket of compositions (ADR 0593 §6)
+		nodes = p.inputs().Nodes // every node's bucket of compositions (ADR 0593 §6)
 	}
 	a := Assert(module, v.Manifest, m, nodes, held, heldErr)
 	out := map[string]any{"assertion": a}
diff --git a/modules/mesh-grants/module.json b/modules/mesh-grants/module.json
index 5363b8ca..e0e69f04 100644
--- a/modules/mesh-grants/module.json
+++ b/modules/mesh-grants/module.json
@@ -22,7 +22,9 @@
     "mesh-delivery-indexer.views.manifests",
     "mesh-delivery-indexer.views.modules",
     "mesh-catalog.manifest-accepted",
-    "mesh-catalog.manifest-refused"
+    "mesh-catalog.manifest-refused",
+    "mesh-catalog.seat-definition-changed",
+    "mesh-catalog.seat-definition-removed"
   ],
   "uses": [
     "operator-channel"
@@ -37,6 +39,7 @@
     "mesh-delivery-indexer.manifests",
     "mesh-delivery-indexer.modules",
     "mesh-delivery-indexer.verdicts",
+    "seat:mesh-catalog.seat-definitions",
     "seat:mesh-hand-acts.hand-act"
   ],
   "emits": [
@@ -56,7 +59,9 @@
     "grants_consumer_match",
     "grants_accept_hashes",
     "grants_first_views",
-    "grants_first_view_again"
+    "grants_first_view_again",
+    "grants_seat_list",
+    "grants_seat_list_again"
   ],
   "state": [
     {