diff --git a/packages/iios-service/src/adapters/adapters.spec.ts b/packages/iios-service/src/adapters/adapters.spec.ts
index beeeabe..ff30dd1 100644
--- a/packages/iios-service/src/adapters/adapters.spec.ts
+++ b/packages/iios-service/src/adapters/adapters.spec.ts
@@ -133,4 +133,15 @@ describe('Adapter outbound (P5)', () => {
     expect(cmd.status).toBe('BLOCKED');
     expect(await prisma.iiosDeliveryAttempt.count({ where: { commandId: cmd.id, status: 'SENT' } })).toBe(0);
   });
+
+  it('per-tenant quota: a noisy tenant is capped while another still sends (P9 slice 3)', async () => {
+    const svc = outbound();
+    svc.tenantLimit = 1;
+    const a1 = await svc.send('WEBHOOK', 't1', {}, 'ta-1', 'scope-A');
+    const a2 = await svc.send('WEBHOOK', 't2', {}, 'ta-2', 'scope-A'); // A over its cap
+    const b1 = await svc.send('WEBHOOK', 't3', {}, 'tb-1', 'scope-B'); // B unaffected
+    expect(a1.status).toBe('SENT');
+    expect(a2.status).toBe('RATE_LIMITED');
+    expect(b1.status).toBe('SENT');
+  });
 });
diff --git a/packages/iios-service/src/adapters/outbound.service.ts b/packages/iios-service/src/adapters/outbound.service.ts
index 66ea1cd..2bb8b2a 100644
--- a/packages/iios-service/src/adapters/outbound.service.ts
+++ b/packages/iios-service/src/adapters/outbound.service.ts
@@ -15,6 +15,9 @@ export class OutboundService {
   /** Public so tests can lower them; default from env. */
   limit = Number(process.env.IIOS_OUTBOUND_LIMIT ?? 5);
   windowMs = Number(process.env.IIOS_OUTBOUND_WINDOW_MS ?? 60_000);
+  /** Per-tenant (scope) egress cap — noisy-neighbor protection (P9). */
+  tenantLimit = Number(process.env.IIOS_TENANT_OUTBOUND_LIMIT ?? 10_000);
+  tenantWindowMs = Number(process.env.IIOS_TENANT_OUTBOUND_WINDOW_MS ?? 60_000);
 
   constructor(
     private readonly prisma: PrismaService,
@@ -32,16 +35,17 @@ export class OutboundService {
     const existing = await this.prisma.iiosOutboundCommand.findUnique({ where: { idempotencyKey } });
     if (existing) return existing;
 
-    if (!(await this.allow(channelType, target))) {
+    // Per-target rate limit AND per-tenant quota (a noisy tenant can't starve shared egress).
+    if (!(await this.allow(channelType, target)) || !(await this.allowTenant(scopeId))) {
       const cmd = await this.prisma.iiosOutboundCommand.create({
-        data: { channelType, target, payload: payload as Prisma.InputJsonValue, status: 'RATE_LIMITED', idempotencyKey },
+        data: { channelType, target, scopeId, payload: payload as Prisma.InputJsonValue, status: 'RATE_LIMITED', idempotencyKey },
       });
       await this.prisma.iiosDeliveryAttempt.create({ data: { commandId: cmd.id, attemptNo: 1, status: 'RATE_LIMITED' } });
       return cmd;
     }
 
     const cmd = await this.prisma.iiosOutboundCommand.create({
-      data: { channelType, target, payload: payload as Prisma.InputJsonValue, status: 'PENDING', idempotencyKey },
+      data: { channelType, target, scopeId, payload: payload as Prisma.InputJsonValue, status: 'PENDING', idempotencyKey },
     });
 
     let result;
@@ -68,6 +72,14 @@ export class OutboundService {
     return updated;
   }
 
+  /** Per-tenant egress quota (P9): count this scope's commands in the window vs the cap. */
+  private async allowTenant(scopeId?: string): Promise<boolean> {
+    if (!scopeId) return true; // unscoped sends are not tenant-limited
+    const since = new Date(Date.now() - this.tenantWindowMs);
+    const count = await this.prisma.iiosOutboundCommand.count({ where: { scopeId, createdAt: { gte: since } } });
+    return count < this.tenantLimit;
+  }
+
   /** Token/window bucket keyed by (channelType, target). Resets when the window elapses. */
   private async allow(channelType: string, target: string): Promise<boolean> {
     const now = new Date();
diff --git a/packages/iios-service/src/isolation.spec.ts b/packages/iios-service/src/isolation.spec.ts
index a31f8a9..f5ad4c3 100644
--- a/packages/iios-service/src/isolation.spec.ts
+++ b/packages/iios-service/src/isolation.spec.ts
@@ -46,6 +46,7 @@ describe('Tenant isolation (P9 / KG-10 — cross-tenant blast radius)', () => {
   it('tenant B cannot read or mutate tenant A resources, and sees none of them', async () => {
     // ── Seed tenant A: a route decision, an AI artifact, a meeting ──
     const scopeA = await actors.resolveScope(A);
+    expect(scopeA.cellId).toBeTruthy(); // new scopes carry a cell assignment (P9 cell hook)
     const interactionId = await interactionFor(A);
     await prisma.iiosRouteBinding.create({
       data: { scopeId: scopeA.id, originChannelType: 'WHATSAPP', originRef: 'adult-group', destinationChannelType: 'PORTAL', destinationRef: 'adults', requiresReview: true, enabled: true },