diff --git a/go/buscompose/names_test.go b/go/buscompose/names_test.go
index 3284dff2..c934da93 100644
--- a/go/buscompose/names_test.go
+++ b/go/buscompose/names_test.go
@@ -29,6 +29,10 @@ func TestTheBusNamesAgree(t *testing.T) {
 	if got := (Principal{Kind: KindLedger, Node: "a", Module: "m"}).Username(); got != "ledger.a.m" {
 		t.Fatalf("a ledger account is named %q", got)
 	}
+	// G §469: a state's bucket is capped at its max-mib; naming none is unbounded.
+	if (Bucket{}).MaxBytes() != -1 || (Bucket{MaxMiB: 2}).MaxBytes() != 2<<20 {
+		t.Fatal("a bucket's cap is not its max-mib in bytes")
+	}
 	// A seat's family is the shared events stream filtered to its subjects: a definition says the stream's age.
 	for _, st := range MeshStreams() {
 		if st.Name == EventsStream && int64(st.MaxAge) != seatdef.SharedEventsMaxAgeDays*24*60*60 {
diff --git a/go/buscompose/state.go b/go/buscompose/state.go
index 1a84d114..8e2d7340 100644
--- a/go/buscompose/state.go
+++ b/go/buscompose/state.go
@@ -24,6 +24,16 @@ type Bucket struct {
 	// KeyTTL says the bucket allows a time to live per key (novox/hq ADR 0433 §1): its owner writes each key with its
 	// own, and the server writes a delete marker, kept KeyTTLMarkerTTL, when it ends.
 	KeyTTL bool
+	// MaxMiB is the bucket's cap in MiB (design 47 G §469); zero is no cap.
+	MaxMiB int
+}
+
+// MaxBytes is the bucket's cap in bytes as the bus's maximum size: -1, unbounded, where it names none.
+func (b Bucket) MaxBytes() int64 {
+	if b.MaxMiB <= 0 {
+		return -1
+	}
+	return int64(b.MaxMiB) * 1024 * 1024
 }
 
 // BucketName is the bucket a module's state lives in: the module and the local name joined by an
diff --git a/go/catalogue/state.go b/go/catalogue/state.go
index 2bca54ed..daf041a9 100644
--- a/go/catalogue/state.go
+++ b/go/catalogue/state.go
@@ -35,11 +35,14 @@ type StateDeclaration struct {
 	// the tool runner's account, read it and never write it (the lead's ruling, 2026-11-04: nats' warrant spend record
 	// `spent`). The judge's rule and the grants follow from it.
 	ReadOnly bool `json:"read-only,omitempty"`
+	// MaxMiB is the bucket's cap in MiB, between ObjectsLeastMiB and ObjectsMostMiB, as an old objects section's
+	// is (design 47 G §469, §695); zero is no cap, as on main.
+	MaxMiB int `json:"max-mib,omitempty"`
 	// KeptLayout is the layout its holder says it writes: its form and its catch-up tool (design 47).
 	KeptLayout
 }
 
-// UnmarshalJSON reads a bucket as its bare name, or as {name, history, ttl-seconds, per-machine, key-ttl, read-only, form, catch-up}.
+// UnmarshalJSON reads a bucket as its bare name, or as {name, history, ttl-seconds, per-machine, key-ttl, read-only, max-mib, form, catch-up}.
 func (s *StateDeclaration) UnmarshalJSON(raw []byte) error {
 	trimmed := bytes.TrimSpace(raw)
 	if len(trimmed) > 0 && trimmed[0] == '"' {
@@ -47,21 +50,28 @@ func (s *StateDeclaration) UnmarshalJSON(raw []byte) error {
 	}
 	type plain StateDeclaration
 	var full plain
+	var said struct {
+		MaxMiB *int `json:"max-mib"`
+	}
+	_ = json.Unmarshal(trimmed, &said)
 	dec := json.NewDecoder(bytes.NewReader(trimmed))
 	dec.DisallowUnknownFields()
 	if err := dec.Decode(&full); err != nil {
-		return fmt.Errorf("a state is either a name or {name, history, ttl-seconds, per-machine, key-ttl, read-only, form, catch-up}: %w", typedUnknown(err))
+		return fmt.Errorf("a state is either a name or {name, history, ttl-seconds, per-machine, key-ttl, read-only, max-mib, form, catch-up}: %w", typedUnknown(err))
 	}
 	if err := full.KeptLayout.refuse(fmt.Sprintf("state %q", full.Name)); err != nil {
 		return err
 	}
+	if said.MaxMiB != nil && (*said.MaxMiB < ObjectsLeastMiB || *said.MaxMiB > ObjectsMostMiB) {
+		return fmt.Errorf("state %q: max-mib is between %d and %d, not %d", full.Name, ObjectsLeastMiB, ObjectsMostMiB, *said.MaxMiB)
+	}
 	*s = StateDeclaration(full)
 	return nil
 }
 
 // MarshalJSON writes back the short form when there is nothing else to say.
 func (s StateDeclaration) MarshalJSON() ([]byte, error) {
-	if s.History == 0 && s.TTLSeconds == 0 && !s.PerMachine && !s.KeyTTL && !s.ReadOnly && s.KeptLayout == (KeptLayout{}) {
+	if s.History == 0 && s.TTLSeconds == 0 && !s.PerMachine && !s.KeyTTL && !s.ReadOnly && s.MaxMiB == 0 && s.KeptLayout == (KeptLayout{}) {
 		return json.Marshal(s.Name)
 	}
 	type plain StateDeclaration
diff --git a/go/catalogue/state_test.go b/go/catalogue/state_test.go
index 0da094f7..a5549cc1 100644
--- a/go/catalogue/state_test.go
+++ b/go/catalogue/state_test.go
@@ -46,6 +46,22 @@ func TestAStateMayHaveKeysThatExpireOneByOne(t *testing.T) {
 	if string(out) != `[{"name":"pulse","key-ttl":true},"stuck",{"name":"seen","history":5},{"name":"spent","read-only":true}]` {
 		t.Fatalf("written back as %s", out)
 	}
+	// G §469, §695: an old state entry takes max-mib, written back, bounded as an objects section's.
+	capped, err := decodeForTest([]byte(`{"module":"x","version":"1","state":[{"name":"a","max-mib":256},"b"]}`))
+	if err != nil || capped.State[0].MaxMiB != 256 || capped.State[1].MaxMiB != 0 {
+		t.Fatalf("max-mib read as %+v, %v", capped.State, err)
+	}
+	if out, _ := json.Marshal(capped.State); string(out) != `[{"name":"a","max-mib":256},"b"]` {
+		t.Fatalf("max-mib written back as %s", out)
+	}
+	for _, bad := range []string{"0", "-1", "8193"} {
+		if _, err := decodeForTest([]byte(`{"module":"x","version":"1","state":[{"name":"a","max-mib":` + bad + `}]}`)); err == nil {
+			t.Errorf("max-mib %s was read", bad)
+		}
+	}
+	if _, err := decodeForTest([]byte(`{"module":"x","version":"1","state":[{"name":"a","max-mib":8192}]}`)); err != nil {
+		t.Errorf("max-mib 8192 refused: %v", err)
+	}
 	if _, err := decodeForTest([]byte(`{"module":"nats","version":"1","state":[{"name":"spent","read-only":true,"read-only":false}]}`)); err == nil ||
 		!strings.Contains(err.Error(), "the field state[0].read-only is given twice") {
 		t.Fatalf("read-only given twice: %v", err)