diff --git a/modules/claude-licence-manager/cmd/claude-licence-manager/main.go b/modules/claude-licence-manager/cmd/claude-licence-manager/main.go
index f48ffa1bb..a43e4a38d 100644
--- a/modules/claude-licence-manager/cmd/claude-licence-manager/main.go
+++ b/modules/claude-licence-manager/cmd/claude-licence-manager/main.go
@@ -86,8 +86,13 @@ func manager() (*Manager, error) {
 			}
 			return a, json.Unmarshal(raw, &a)
 		},
-		Reported:     heard.Of,
-		Emit:         func(event string, body map[string]any) error { return stdio.Emit(event, body) },
+		Reported: heard.Of,
+		Emit:     func(event string, body map[string]any) error { return stdio.Emit(event, body) },
+		Tell: func(_ context.Context, headline string, lines []string) error {
+			_, err := stdio.Ask("seat:operator-channel.tell", map[string]any{"subject": Seat, "headline": headline,
+				"lines": lines})
+			return err
+		},
 		Now:          time.Now,
 		Log:          say,
 		Holder:       fmt.Sprintf("%s:%d", node, os.Getpid()),
diff --git a/modules/claude-licence-manager/cmd/claude-licence-manager/manager.go b/modules/claude-licence-manager/cmd/claude-licence-manager/manager.go
index 040a9ecc9..4b0616b47 100644
--- a/modules/claude-licence-manager/cmd/claude-licence-manager/manager.go
+++ b/modules/claude-licence-manager/cmd/claude-licence-manager/manager.go
@@ -148,8 +148,10 @@ type Manager struct {
 	// Reported is the binding generation a node last reported applying (B11), 0 when none is known.
 	Reported func(node string) int64
 	Emit     func(event string, body map[string]any) error
-	Now      func() time.Time
-	Log      func(format string, args ...any)
+	// Tell tells the operator one notice that needs no answer, through the seat operator-channel's tell (§28).
+	Tell func(ctx context.Context, headline string, lines []string) error
+	Now  func() time.Time
+	Log  func(format string, args ...any)
 	// Holder names this process in a lease, so a second run is told apart.
 	Holder string
 	// Settings are those in force, read again from SettingsFile at every reading (settings.go); an empty SettingsFile
@@ -693,6 +695,10 @@ func (m *Manager) ReadUsage(ctx context.Context) error {
 			"sessionResetsAt": reading.SessionResetsAt, "weeklyPct": reading.WeeklyPct,
 			"weeklyResetsAt": reading.WeeklyResetsAt, "sonnetPct": reading.SonnetPct,
 			"sonnetResetsAt": reading.SonnetResetsAt})
+		// On each reading, a licence at its threshold moves every consumer bound to it (§26).
+		if _, err := m.ApplyRule(ctx, l.Name, false, false); err != nil {
+			return err
+		}
 	}
 	return nil
 }
diff --git a/modules/claude-licence-manager/cmd/claude-licence-manager/switching.go b/modules/claude-licence-manager/cmd/claude-licence-manager/switching.go
new file mode 100644
index 000000000..e321ed7e0
--- /dev/null
+++ b/modules/claude-licence-manager/cmd/claude-licence-manager/switching.go
@@ -0,0 +1,163 @@
+package main
+
+// The switch rule (design 39 bus-and-switch §26, §27, §28, §32): after a reading of licence L, when switch_auto is on and
+// L, with one or more consumers bound to it, is at or above switch_at_pct in its session or weekly window, every
+// consumer bound to L moves, in one act, to the other licence with known room whose windows are both below
+// room_below_pct and that has the most room, the first by name on a tie. The act is said as one licence.switched, a
+// binding.changed per consumer, one audit entry switched, and told to the operator. A consumer is only ever moved off
+// a licence at its threshold, so none flaps between two.
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// ByUsage is who moves a consumer by the rule (§26).
+const ByUsage = "usage"
+
+// Switch is one act of the rule: from L to the target, the consumers it moves, the window of L that reached its
+// threshold, its percentage and reset, and the target's room.
+type Switch struct {
+	From      string   `json:"from"`
+	To        string   `json:"to"`
+	Consumers []string `json:"consumers"`
+	Window    string   `json:"window"`
+	Pct       float64  `json:"pct"`
+	ResetsAt  string   `json:"resetsAt"`
+	Room      float64  `json:"room"`
+}
+
+// why is the cause a moved binding carries: L, the window, its percentage and its reset (§26).
+func (s Switch) why() string {
+	return fmt.Sprintf("%s reached %g %% of its %s window, which resets at %s", s.From, s.Pct, s.Window, s.ResetsAt)
+}
+
+// fields are the act's fields, the same in licence.switched and the audit entry switched (§27).
+func (s Switch) fields() map[string]any {
+	f := switchedFields(s.From, s.To, s.Consumers, Cause{Why: s.why(), By: ByUsage})
+	f["window"], f["pct"], f["resetsAt"], f["room"] = s.Window, s.Pct, s.ResetsAt, s.Room
+	return f
+}
+
+// Rule is what the rule finds for one licence at its threshold: the act, or none with NoTarget when no other licence
+// has room.
+type Rule struct {
+	Switch   *Switch
+	NoTarget bool
+}
+
+// RuleFor is what §26 gives for licence l among every licence and binding, under the settings s. A licence below its
+// threshold, or with no consumer, gives nothing.
+func (m *Manager) RuleFor(l Licence, licences []Licence, bindings []Binding, s Settings) Rule {
+	var consumers []string
+	for _, b := range bindings {
+		if b.Licence == l.Name {
+			consumers = append(consumers, b.Consumer)
+		}
+	}
+	if len(consumers) == 0 || l.Usage == nil {
+		return Rule{}
+	}
+	sw := Switch{From: l.Name, Consumers: consumers}
+	session, weekly := l.Usage.SessionPct, l.Usage.WeeklyPct
+	switch {
+	case session != nil && *session >= s.SwitchAt && (weekly == nil || *session >= *weekly):
+		sw.Window, sw.Pct, sw.ResetsAt = "session", *session, l.Usage.SessionResetsAt
+	case weekly != nil && *weekly >= s.SwitchAt:
+		sw.Window, sw.Pct, sw.ResetsAt = "weekly", *weekly, l.Usage.WeeklyResetsAt
+	default:
+		return Rule{}
+	}
+	sort.Strings(sw.Consumers)
+	others := append([]Licence(nil), licences...)
+	sort.Slice(others, func(i, j int) bool { return others[i].Name < others[j].Name })
+	best := -1.0
+	for _, o := range others {
+		if o.Name == l.Name {
+			continue
+		}
+		room, known := Room(o, m.Now(), s)
+		if !known || *o.Usage.SessionPct >= s.RoomBelow || *o.Usage.WeeklyPct >= s.RoomBelow || room <= best {
+			continue
+		}
+		best, sw.To, sw.Room = room, o.Name, room
+	}
+	if sw.To == "" {
+		return Rule{NoTarget: true}
+	}
+	return Rule{Switch: &sw}
+}
+
+// ApplyRule applies §26 to one licence, or to every one when licence is empty: after a reading, by switch_auto, or by
+// hand, even with switch_auto off (§32, §39). With dry it answers the moves and moves nothing. An invalid pair of
+// settings moves no consumer (§33).
+func (m *Manager) ApplyRule(ctx context.Context, licence string, byHand, dry bool) ([]Switch, error) {
+	s := m.settings()
+	if (!s.SwitchAuto && !byHand) || len(s.Invalid()) > 0 {
+		return nil, nil
+	}
+	licences, err := m.Store.Licences(ctx)
+	if err != nil {
+		return nil, err
+	}
+	bindings, err := m.Store.Bindings(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var acts []Switch
+	for _, l := range licences {
+		if licence != "" && l.Name != licence {
+			continue
+		}
+		r := m.RuleFor(l, licences, bindings, s)
+		if r.Switch == nil {
+			continue
+		}
+		acts = append(acts, *r.Switch)
+		if dry {
+			continue
+		}
+		if err := m.act(ctx, *r.Switch, licences); err != nil {
+			return acts, err
+		}
+		// What was moved is bound to the target now, for the next licence's rule.
+		if bindings, err = m.Store.Bindings(ctx); err != nil {
+			return acts, err
+		}
+	}
+	return acts, nil
+}
+
+// act moves every consumer of one act as the switch verb does, then says the act once and tells the operator (§26 to
+// §28).
+func (m *Manager) act(ctx context.Context, sw Switch, licences []Licence) error {
+	kind := ""
+	for _, l := range licences {
+		if l.Name == sw.To {
+			kind = l.Kind
+		}
+	}
+	floor := m.floorIn(nil)
+	for _, consumer := range sw.Consumers {
+		b, err := m.Store.Bind(ctx, consumer, sw.To, Move{Kind: kind, Why: sw.why(), By: ByUsage, Floor: floor})
+		if err != nil {
+			return fmt.Errorf("moving %s to %s: %w", consumer, sw.To, err)
+		}
+		m.changed(b, sw.From)
+	}
+	f := sw.fields()
+	if err := m.record(ctx, "switched", fmt.Sprintf("switched %s from %s to %s: %s; by %s",
+		strings.Join(sw.Consumers, ", "), sw.From, sw.To, sw.why(), ByUsage), f); err != nil {
+		return err
+	}
+	_ = m.Emit("licence.switched", f)
+	if m.Tell != nil {
+		line := fmt.Sprintf("%s; %s has %g %% room", sw.why(), sw.To, sw.Room)
+		if err := m.Tell(ctx, strings.Join(sw.Consumers, ", ")+" moved to "+sw.To, []string{line}); err != nil {
+			m.Log("the switch of %s to %s could not be told: %v", strings.Join(sw.Consumers, ", "), sw.To, err)
+		}
+	}
+	return nil
+}
diff --git a/modules/claude-licence-manager/cmd/claude-licence-manager/switching_test.go b/modules/claude-licence-manager/cmd/claude-licence-manager/switching_test.go
new file mode 100644
index 000000000..3dfa8e8da
--- /dev/null
+++ b/modules/claude-licence-manager/cmd/claude-licence-manager/switching_test.go
@@ -0,0 +1,181 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+)
+
+// read is a licence's latest reading, read at t0.
+func read(session, weekly float64) *UsageReading {
+	return &UsageReading{SessionPct: &session, SessionResetsAt: "2026-11-11T23:00:00Z", WeeklyPct: &weekly,
+		WeeklyResetsAt: "2026-11-14T09:00:00Z", ReadAt: t0.UTC().Format(time.RFC3339Nano)}
+}
+
+func sub(name string, u *UsageReading) Licence {
+	return Licence{Name: name, Kind: "subscription", Generation: 1, Usage: u}
+}
+
+// design 39 bus-and-switch §26/AC1, §25, §48: a table of licences, readings and bindings and the moves each gives.
+func TestTheRuleMovesEachTable(t *testing.T) {
+	mm := newMesh(t)
+	on := func(consumers ...string) []Binding {
+		var out []Binding
+		for _, c := range consumers {
+			out = append(out, Binding{Consumer: c, Licence: "a"})
+		}
+		return out
+	}
+	for _, c := range []struct {
+		name      string
+		licences  []Licence
+		bindings  []Binding
+		to        string
+		window    string
+		noTarget  bool
+		consumers int
+	}{
+		{"below its threshold", []Licence{sub("a", read(50, 98)), sub("b", read(0, 0))}, on("x"), "", "", false, 0},
+		{"no consumer", []Licence{sub("a", read(99, 99)), sub("b", read(0, 0))}, nil, "", "", false, 0},
+		{"the weekly window at 99", []Licence{sub("a", read(40, 99)), sub("b", read(10, 30)), sub("c", read(5, 20))},
+			on("x", "y", "z", "w"), "c", "weekly", false, 4},
+		{"the session window at 100", []Licence{sub("a", read(100, 50)), sub("b", read(10, 30))}, on("x"), "b", "session", false, 1},
+		{"a tie goes to the first by name", []Licence{sub("a", read(99, 0)), sub("c", read(10, 10)), sub("b", read(10, 10))},
+			on("x"), "b", "session", false, 1},
+		{"a target's windows both below room_below_pct", []Licence{sub("a", read(99, 0)), sub("b", read(0, 90)),
+			sub("c", read(89, 89))}, on("x"), "c", "session", false, 1},
+		{"no other licence has room", []Licence{sub("a", read(99, 0)), sub("b", read(95, 0)),
+			{Name: "k", Kind: "api-key", Generation: 1}}, on("x"), "", "", true, 0},
+		{"an unread licence is no target", []Licence{sub("a", read(0, 99)), sub("b", nil)}, on("x"), "", "", true, 0},
+	} {
+		r := mm.m.RuleFor(c.licences[0], c.licences, c.bindings, Defaults)
+		to, window, n := "", "", 0
+		if r.Switch != nil {
+			to, window, n = r.Switch.To, r.Switch.Window, len(r.Switch.Consumers)
+		}
+		if to != c.to || window != c.window || n != c.consumers || r.NoTarget != c.noTarget {
+			t.Errorf("%s: to %q window %q consumers %d no target %v", c.name, to, window, n, r.NoTarget)
+		}
+	}
+}
+
+// fourOnA is four consumers bound to a, at 99 % of its weekly window, b with 70 % room and c with 60 %.
+func fourOnA(t *testing.T) *miniMesh {
+	mm := newMesh(t)
+	ctx := context.Background()
+	for _, l := range []Licence{sub("a", read(40, 99)), sub("b", read(30, 20)), sub("c", read(40, 10))} {
+		_ = mm.store.SaveLicence(ctx, l)
+	}
+	for _, c := range []string{"ace", "g14", "laptop", "server"} {
+		_, _ = mm.store.Bind(ctx, c, "a", Move{Kind: "subscription", Why: "set", By: "test"})
+	}
+	mm.events = nil
+	return mm
+}
+
+// design 39 bus-and-switch §27/AC1, §26, §21: one act says one licence.switched with the consumers moved, the window,
+// its percentage, reset and the target's room; one binding.changed per consumer; one audit entry switched with the same
+// fields; each binding moved by usage, its why naming the licence, the window, the percentage and the reset.
+func TestOneSwitchedPerAct(t *testing.T) {
+	mm := fourOnA(t)
+	acts, err := mm.m.ApplyRule(context.Background(), "", false, false)
+	if err != nil || len(acts) != 1 || acts[0].To != "b" || acts[0].Room != 70 {
+		t.Fatalf("acts %+v %v", acts, err)
+	}
+	var switched []map[string]any
+	changed := 0
+	for _, e := range mm.events {
+		name, body, _ := strings.Cut(e, " ")
+		var f map[string]any
+		_ = json.Unmarshal([]byte(body), &f)
+		switch name {
+		case "licence.switched":
+			switched = append(switched, f)
+		case "binding.changed":
+			changed++
+		}
+	}
+	if len(switched) != 1 || changed != 4 {
+		t.Fatalf("said %v", mm.events)
+	}
+	s := switched[0]
+	if s["from"] != "a" || s["to"] != "b" || len(s["consumers"].([]any)) != 4 || s["by"] != ByUsage ||
+		s["window"] != "weekly" || s["pct"] != 99.0 || s["resetsAt"] != "2026-11-14T09:00:00Z" || s["room"] != 70.0 {
+		t.Fatalf("licence.switched %v", s)
+	}
+	audit := mm.audit.under("switched")
+	if len(audit) != 1 || audit[0]["window"] != "weekly" || len(audit[0]["consumers"].([]any)) != 4 {
+		t.Fatalf("audit %v", audit)
+	}
+	b := mm.bound("laptop")
+	if b.Licence != "b" || b.By != ByUsage || b.Why != "a reached 99 % of its weekly window, which resets at 2026-11-14T09:00:00Z" {
+		t.Fatalf("laptop %+v", b)
+	}
+}
+
+// design 39 bus-and-switch §28/AC1: the rule tells the operator once per act, and the switch verb never.
+func TestTheRuleTellsOnceAndTheVerbNever(t *testing.T) {
+	mm := fourOnA(t)
+	var told []string
+	mm.m.Tell = func(_ context.Context, headline string, lines []string) error {
+		told = append(told, headline+" | "+strings.Join(lines, " "))
+		return nil
+	}
+	_, _ = mm.m.ApplyRule(context.Background(), "", false, false)
+	if len(told) != 1 || told[0] != "ace, g14, laptop, server moved to b | a reached 99 % of its weekly window, "+
+		"which resets at 2026-11-14T09:00:00Z; b has 70 % room" {
+		t.Fatalf("told %v", told)
+	}
+	_, _ = mm.m.Bind(WithCause(context.Background(), Cause{Why: "the switch verb", By: "a person"}), "ace", "c")
+	if len(told) != 1 {
+		t.Fatalf("the switch verb told %v", told)
+	}
+}
+
+// design 39 bus-and-switch §32/AC1, §33/AC2: dry answers the same moves as the act and moves nothing; an invalid pair
+// of settings, or switch_auto off, moves nothing after a reading, and the rule by hand runs with switch_auto off.
+func TestDryAnswersTheSameMovesAndMovesNothing(t *testing.T) {
+	ctx := context.Background()
+	mm := fourOnA(t)
+	dry, err := mm.m.ApplyRule(ctx, "a", true, true)
+	if err != nil || len(dry) != 1 || mm.bound("ace").Licence != "a" || len(mm.events) != 0 {
+		t.Fatalf("dry %+v %v, said %v", dry, err, mm.events)
+	}
+	acts, _ := mm.m.ApplyRule(ctx, "a", true, false)
+	if len(acts) != 1 || acts[0].To != dry[0].To || strings.Join(acts[0].Consumers, ",") != strings.Join(dry[0].Consumers, ",") {
+		t.Fatalf("dry %+v, act %+v", dry, acts)
+	}
+	for name, change := range map[string]func(*Settings){
+		"an invalid pair": func(s *Settings) { s.RoomBelow = 100 },
+		"switch_auto off": func(s *Settings) { s.SwitchAuto = false },
+	} {
+		mm := fourOnA(t)
+		change(&mm.m.Settings)
+		if acts, _ := mm.m.ApplyRule(ctx, "", false, false); len(acts) != 0 || mm.bound("ace").Licence != "a" {
+			t.Errorf("%s moved %+v", name, acts)
+		}
+	}
+	mm = fourOnA(t)
+	mm.m.Settings.SwitchAuto = false
+	if acts, _ := mm.m.ApplyRule(ctx, "", true, false); len(acts) != 1 || mm.bound("ace").Licence != "b" {
+		t.Fatalf("by hand with switch_auto off moved %+v", acts)
+	}
+}
+
+// design 39 bus-and-switch §26: a reading at the threshold applies the rule at once.
+func TestAReadingAtTheThresholdApplies(t *testing.T) {
+	mm := newMesh(t)
+	ctx := context.Background()
+	_, _ = mm.m.Consider(ctx, []Holdings{mm.login("laptop", "rt-a", true, t0)})
+	_ = mm.store.SaveLicence(ctx, Licence{Name: "b@example.org", Kind: "subscription", Usage: read(10, 10)})
+	mm.vendor.usage = map[string]any{"five_hour": map[string]any{"utilization": 30.0},
+		"seven_day": map[string]any{"utilization": 99.0, "resets_at": "2026-11-14T09:00:00Z"}}
+	if err := mm.m.ReadUsage(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if b := mm.bound("laptop"); b.Licence != "b@example.org" || b.By != ByUsage {
+		t.Fatalf("laptop %+v", b)
+	}
+}