diff --git a/runners/agent-runner/src/index.ts b/runners/agent-runner/src/index.ts
index a806117..efc2416 100644
--- a/runners/agent-runner/src/index.ts
+++ b/runners/agent-runner/src/index.ts
@@ -21,6 +21,11 @@ import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js';
 import { fileURLToPath } from 'url';
 
+import {
+  prependRoomRoleHeader,
+  type RoomRoleContext,
+} from './room-role-context.js';
+
 interface ContainerInput {
   prompt: string;
   sessionId?: string;
@@ -30,6 +35,7 @@ interface ContainerInput {
   isScheduledTask?: boolean;
   assistantName?: string;
   secrets?: Record<string, string>;
+  roomRoleContext?: RoomRoleContext;
 }
 
 /** Mirrors AgentOutput in src/agent-runner.ts (separate package, can't import directly). */
@@ -971,6 +977,7 @@ async function main(): Promise<void> {
     log(`Draining ${pending.length} pending IPC messages into initial prompt`);
     prompt += '\n' + pending.join('\n');
   }
+  prompt = prependRoomRoleHeader(prompt, containerInput.roomRoleContext);
 
   // --- Slash command handling ---
   // Only known session slash commands are handled here. This prevents
diff --git a/runners/agent-runner/src/room-role-context.ts b/runners/agent-runner/src/room-role-context.ts
new file mode 100644
index 0000000..19d9381
--- /dev/null
+++ b/runners/agent-runner/src/room-role-context.ts
@@ -0,0 +1,23 @@
+export interface RoomRoleContext {
+  serviceId: string;
+  role: 'owner' | 'reviewer';
+  ownerServiceId: string;
+  reviewerServiceId: string;
+  failoverOwner: boolean;
+}
+
+export function prependRoomRoleHeader(
+  prompt: string,
+  roomRoleContext?: RoomRoleContext,
+): string {
+  if (!roomRoleContext) {
+    return prompt;
+  }
+
+  const header =
+    `[ROOM_ROLE self=${roomRoleContext.serviceId} role=${roomRoleContext.role} ` +
+    `owner=${roomRoleContext.ownerServiceId} reviewer=${roomRoleContext.reviewerServiceId} ` +
+    `failover=${roomRoleContext.failoverOwner ? 1 : 0}]`;
+
+  return `${header}\n\n${prompt}`;
+}
diff --git a/runners/agent-runner/test/room-role-context.test.ts b/runners/agent-runner/test/room-role-context.test.ts
new file mode 100644
index 0000000..4ada0d4
--- /dev/null
+++ b/runners/agent-runner/test/room-role-context.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+
+import { prependRoomRoleHeader } from '../src/room-role-context.js';
+
+describe('claude runner room role header', () => {
+  it('prepends a canonical role header when metadata exists', () => {
+    expect(
+      prependRoomRoleHeader('hello', {
+        serviceId: 'codex-review',
+        role: 'owner',
+        ownerServiceId: 'codex-review',
+        reviewerServiceId: 'codex-main',
+        failoverOwner: true,
+      }),
+    ).toBe(
+      '[ROOM_ROLE self=codex-review role=owner owner=codex-review reviewer=codex-main failover=1]\n\nhello',
+    );
+  });
+
+  it('leaves prompts unchanged without room metadata', () => {
+    expect(prependRoomRoleHeader('hello')).toBe('hello');
+  });
+});
diff --git a/runners/codex-runner/src/index.ts b/runners/codex-runner/src/index.ts
index b45183a..ee7f1f6 100644
--- a/runners/codex-runner/src/index.ts
+++ b/runners/codex-runner/src/index.ts
@@ -19,6 +19,10 @@ import {
   CodexAppServerClient,
   type AppServerInputItem,
 } from './app-server-client.js';
+import {
+  prependRoomRoleHeader,
+  type RoomRoleContext,
+} from './room-role-context.js';
 
 // ── Types ──────────────────────────────────────────────────────────
 
@@ -31,6 +35,7 @@ interface ContainerInput {
   isScheduledTask?: boolean;
   assistantName?: string;
   agentType?: string;
+  roomRoleContext?: RoomRoleContext;
 }
 
 interface ContainerOutput {
@@ -464,6 +469,7 @@ async function main(): Promise<void> {
   if (pending.length > 0) {
     prompt += '\n' + pending.join('\n');
   }
+  prompt = prependRoomRoleHeader(prompt, containerInput.roomRoleContext);
 
   try {
     log('Runtime selected: app-server');
diff --git a/runners/codex-runner/src/room-role-context.ts b/runners/codex-runner/src/room-role-context.ts
new file mode 100644
index 0000000..19d9381
--- /dev/null
+++ b/runners/codex-runner/src/room-role-context.ts
@@ -0,0 +1,23 @@
+export interface RoomRoleContext {
+  serviceId: string;
+  role: 'owner' | 'reviewer';
+  ownerServiceId: string;
+  reviewerServiceId: string;
+  failoverOwner: boolean;
+}
+
+export function prependRoomRoleHeader(
+  prompt: string,
+  roomRoleContext?: RoomRoleContext,
+): string {
+  if (!roomRoleContext) {
+    return prompt;
+  }
+
+  const header =
+    `[ROOM_ROLE self=${roomRoleContext.serviceId} role=${roomRoleContext.role} ` +
+    `owner=${roomRoleContext.ownerServiceId} reviewer=${roomRoleContext.reviewerServiceId} ` +
+    `failover=${roomRoleContext.failoverOwner ? 1 : 0}]`;
+
+  return `${header}\n\n${prompt}`;
+}
diff --git a/runners/codex-runner/test/room-role-context.test.ts b/runners/codex-runner/test/room-role-context.test.ts
new file mode 100644
index 0000000..2d5b9c0
--- /dev/null
+++ b/runners/codex-runner/test/room-role-context.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+
+import { prependRoomRoleHeader } from '../src/room-role-context.js';
+
+describe('codex runner room role header', () => {
+  it('prepends a canonical role header when metadata exists', () => {
+    expect(
+      prependRoomRoleHeader('hello', {
+        serviceId: 'codex-main',
+        role: 'reviewer',
+        ownerServiceId: 'claude',
+        reviewerServiceId: 'codex-main',
+        failoverOwner: false,
+      }),
+    ).toBe(
+      '[ROOM_ROLE self=codex-main role=reviewer owner=claude reviewer=codex-main failover=0]\n\nhello',
+    );
+  });
+
+  it('leaves prompts unchanged without room metadata', () => {
+    expect(prependRoomRoleHeader('hello')).toBe('hello');
+  });
+});
diff --git a/src/agent-runner.test.ts b/src/agent-runner.test.ts
index 2e9d9b4..f1bf1b5 100644
--- a/src/agent-runner.test.ts
+++ b/src/agent-runner.test.ts
@@ -312,6 +312,46 @@ describe('agent-runner timeout behavior', () => {
     );
   });
 
+  it('serializes roomRoleContext into the runner stdin payload', async () => {
+    vi.useRealTimers();
+    fakeProc = createFakeProcess();
+
+    let stdinPayload = '';
+    fakeProc.stdin.on('data', (chunk) => {
+      stdinPayload += chunk.toString();
+    });
+
+    const resultPromise = runAgentProcess(
+      testGroup,
+      {
+        ...testInput,
+        roomRoleContext: {
+          serviceId: 'codex-main',
+          role: 'reviewer',
+          ownerServiceId: 'claude',
+          reviewerServiceId: 'codex-main',
+          failoverOwner: false,
+        },
+      },
+      () => {},
+      async () => {},
+    );
+
+    fakeProc.emit('close', 0);
+    const result = await resultPromise;
+    expect(result.status).toBe('success');
+    expect(JSON.parse(stdinPayload)).toMatchObject({
+      prompt: 'Hello',
+      roomRoleContext: {
+        serviceId: 'codex-main',
+        role: 'reviewer',
+        ownerServiceId: 'claude',
+        reviewerServiceId: 'codex-main',
+        failoverOwner: false,
+      },
+    });
+  });
+
   it('isolates IPC and session directories for isolated scheduled tasks', async () => {
     vi.useRealTimers();
     fakeProc = createFakeProcess();
diff --git a/src/agent-runner.ts b/src/agent-runner.ts
index 6b1e5ae..895cfa2 100644
--- a/src/agent-runner.ts
+++ b/src/agent-runner.ts
@@ -24,6 +24,7 @@ import {
   AgentOutputPhase,
   AgentType,
   RegisteredGroup,
+  RoomRoleContext,
   StructuredAgentOutput,
 } from './types.js';
 
@@ -40,6 +41,7 @@ export interface AgentInput {
   useTaskScopedSession?: boolean;
   assistantName?: string;
   agentType?: 'claude-code' | 'codex';
+  roomRoleContext?: RoomRoleContext;
 }
 
 export interface AgentOutput {
diff --git a/src/message-agent-executor.test.ts b/src/message-agent-executor.test.ts
index 31ae1be..54a6dc8 100644
--- a/src/message-agent-executor.test.ts
+++ b/src/message-agent-executor.test.ts
@@ -15,6 +15,9 @@ vi.mock('./config.js', () => ({
   CODEX_REVIEW_SERVICE_ID: 'codex-review',
   DATA_DIR: '/tmp/ejclaw-test-data',
   SERVICE_SESSION_SCOPE: 'claude',
+  normalizeServiceId: vi.fn((serviceId: string) =>
+    serviceId === 'codex' ? 'codex-main' : serviceId,
+  ),
 }));
 
 vi.mock('./db.js', () => ({
@@ -231,6 +234,32 @@ describe('runAgentForGroup room memory', () => {
     );
   });
 
+  it('passes paired-room role metadata through to the runner input', async () => {
+    const group = { ...makeGroup(), folder: 'test-group' };
+
+    await runAgentForGroup(makeDeps(), {
+      group,
+      prompt: 'hello',
+      chatJid: 'group@test',
+      runId: 'run-room-role',
+    });
+
+    expect(agentRunner.runAgentProcess).toHaveBeenCalledWith(
+      group,
+      expect.objectContaining({
+        roomRoleContext: {
+          serviceId: 'claude',
+          role: 'owner',
+          ownerServiceId: 'claude',
+          reviewerServiceId: 'codex-main',
+          failoverOwner: false,
+        },
+      }),
+      expect.any(Function),
+      undefined,
+    );
+  });
+
   it('adds reviewer silence guidance when the current service is the reviewer for the chat', async () => {
     const group = { ...makeGroup(), folder: 'test-group' };
     vi.mocked(serviceRouting.getEffectiveChannelLease).mockReturnValue({
diff --git a/src/message-agent-executor.ts b/src/message-agent-executor.ts
index a283c81..d68f020 100644
--- a/src/message-agent-executor.ts
+++ b/src/message-agent-executor.ts
@@ -12,6 +12,7 @@ import { createServiceHandoff, getAllTasks } from './db.js';
 import { GroupQueue } from './group-queue.js';
 import { logger } from './logger.js';
 import { buildRoomMemoryBriefing } from './memento-client.js';
+import { buildRoomRoleContext } from './room-role-context.js';
 import {
   classifyRotationTrigger,
   type AgentTriggerReason,
@@ -121,6 +122,10 @@ export async function runAgentForGroup(
   const currentLease = getEffectiveChannelLease(chatJid);
   const reviewerMode =
     currentLease.reviewer_service_id === SERVICE_SESSION_SCOPE;
+  const roomRoleContext = buildRoomRoleContext(
+    currentLease,
+    SERVICE_SESSION_SCOPE,
+  );
   const effectivePrompt = buildStructuredOutputPrompt(prompt, {
     reviewerMode,
   });
@@ -180,6 +185,7 @@ export async function runAgentForGroup(
     runId,
     isMain,
     assistantName: deps.assistantName,
+    roomRoleContext,
   };
 
   const runAttempt = async (
diff --git a/src/room-role-context.test.ts b/src/room-role-context.test.ts
new file mode 100644
index 0000000..f40f3a2
--- /dev/null
+++ b/src/room-role-context.test.ts
@@ -0,0 +1,65 @@
+import { describe, expect, it } from 'vitest';
+
+import { buildRoomRoleContext } from './room-role-context.js';
+
+describe('buildRoomRoleContext', () => {
+  it('returns reviewer context for a normal paired codex turn', () => {
+    expect(
+      buildRoomRoleContext(
+        {
+          chat_jid: 'group@test',
+          owner_service_id: 'claude',
+          reviewer_service_id: 'codex-main',
+          activated_at: null,
+          reason: null,
+          explicit: false,
+        },
+        'codex-main',
+      ),
+    ).toEqual({
+      serviceId: 'codex-main',
+      role: 'reviewer',
+      ownerServiceId: 'claude',
+      reviewerServiceId: 'codex-main',
+      failoverOwner: false,
+    });
+  });
+
+  it('returns owner failover context for a codex-review failover turn', () => {
+    expect(
+      buildRoomRoleContext(
+        {
+          chat_jid: 'group@test',
+          owner_service_id: 'codex-review',
+          reviewer_service_id: 'codex-main',
+          activated_at: '2026-03-28T10:00:00.000Z',
+          reason: 'claude-429',
+          explicit: true,
+        },
+        'codex-review',
+      ),
+    ).toEqual({
+      serviceId: 'codex-review',
+      role: 'owner',
+      ownerServiceId: 'codex-review',
+      reviewerServiceId: 'codex-main',
+      failoverOwner: true,
+    });
+  });
+
+  it('returns undefined for a non-paired room', () => {
+    expect(
+      buildRoomRoleContext(
+        {
+          chat_jid: 'solo@test',
+          owner_service_id: 'codex-main',
+          reviewer_service_id: null,
+          activated_at: null,
+          reason: null,
+          explicit: false,
+        },
+        'codex-main',
+      ),
+    ).toBeUndefined();
+  });
+});
diff --git a/src/room-role-context.ts b/src/room-role-context.ts
new file mode 100644
index 0000000..eadb001
--- /dev/null
+++ b/src/room-role-context.ts
@@ -0,0 +1,43 @@
+import {
+  CODEX_MAIN_SERVICE_ID,
+  CODEX_REVIEW_SERVICE_ID,
+  normalizeServiceId,
+} from './config.js';
+import type { RoomRoleContext } from './types.js';
+import type { EffectiveChannelLease } from './service-routing.js';
+
+export function buildRoomRoleContext(
+  lease: EffectiveChannelLease,
+  serviceId: string,
+): RoomRoleContext | undefined {
+  const normalizedServiceId = normalizeServiceId(serviceId);
+  const reviewerServiceId = lease.reviewer_service_id
+    ? normalizeServiceId(lease.reviewer_service_id)
+    : null;
+
+  if (!reviewerServiceId) {
+    return undefined;
+  }
+
+  const ownerServiceId = normalizeServiceId(lease.owner_service_id);
+  const role =
+    ownerServiceId === normalizedServiceId
+      ? 'owner'
+      : reviewerServiceId === normalizedServiceId
+        ? 'reviewer'
+        : null;
+
+  if (!role) {
+    return undefined;
+  }
+
+  return {
+    serviceId: normalizedServiceId,
+    role,
+    ownerServiceId,
+    reviewerServiceId,
+    failoverOwner:
+      ownerServiceId === CODEX_REVIEW_SERVICE_ID &&
+      reviewerServiceId === CODEX_MAIN_SERVICE_ID,
+  };
+}
diff --git a/src/types.ts b/src/types.ts
index 686cac4..f5c27a3 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -23,6 +23,16 @@ export type VisiblePhase = 'silent' | 'progress' | 'final';
 
 export type AgentVisibility = 'public' | 'silent';
 
+export type PairedRoomRole = 'owner' | 'reviewer';
+
+export interface RoomRoleContext {
+  serviceId: string;
+  role: PairedRoomRole;
+  ownerServiceId: string;
+  reviewerServiceId: string;
+  failoverOwner: boolean;
+}
+
 export type StructuredAgentOutput =
   | {
       visibility: 'public';