diff --git a/container/agent-runner/src/integration.test.ts b/container/agent-runner/src/integration.test.ts
index cc537b5..4a2b806 100644
--- a/container/agent-runner/src/integration.test.ts
+++ b/container/agent-runner/src/integration.test.ts
@@ -249,6 +249,51 @@ describe('poll loop integration', () => {
     await loopPromise.catch(() => {});
   });
 
+  it('internal tags between message blocks are stripped from scratchpad', async () => {
+    insertMessage('m1', { sender: 'Alice', text: 'hi' }, { platformId: 'chan-1', channelType: 'discord' });
+
+    const provider = new MockProvider(
+      {},
+      () => '<internal>thinking about this...</internal><message to="discord-test">answer</message><internal>done thinking</internal>',
+    );
+    const controller = new AbortController();
+    const loopPromise = runPollLoopWithTimeout(provider, controller.signal, 2000);
+
+    await waitFor(() => getUndeliveredMessages().length > 0, 2000);
+    controller.abort();
+
+    const out = getUndeliveredMessages();
+    expect(out).toHaveLength(1);
+    expect(JSON.parse(out[0].content).text).toBe('answer');
+
+    await loopPromise.catch(() => {});
+  });
+
+  it('handles mixed task + chat batch with correct origin metadata', async () => {
+    // Seed destination for routing lookup
+    insertMessage('m-chat', { sender: 'Alice', text: 'check this' }, { platformId: 'chan-1', channelType: 'discord' });
+    // Task with same routing — simulates a scheduled task in a channel session
+    getInboundDb()
+      .prepare(
+        `INSERT INTO messages_in (id, kind, timestamp, status, platform_id, channel_type, content)
+         VALUES ('t-task', 'task', datetime('now'), 'pending', 'chan-1', 'discord', ?)`,
+      )
+      .run(JSON.stringify({ prompt: 'daily check' }));
+
+    const provider = new MockProvider({}, () => '<message to="discord-test">done</message>');
+    const controller = new AbortController();
+    const loopPromise = runPollLoopWithTimeout(provider, controller.signal, 2000);
+
+    await waitFor(() => getUndeliveredMessages().length > 0, 2000);
+    controller.abort();
+
+    const out = getUndeliveredMessages();
+    expect(out).toHaveLength(1);
+    expect(out[0].platform_id).toBe('chan-1');
+
+    await loopPromise.catch(() => {});
+  });
+
   it('should inject destination reminder after a compacted event', async () => {
     // Two destinations — required for the reminder to fire (single-destination
     // groups have a fallback path that works without <message to="…"> wrapping).
diff --git a/src/host-core.test.ts b/src/host-core.test.ts
index 043b6b1..70669dd 100644
--- a/src/host-core.test.ts
+++ b/src/host-core.test.ts
@@ -19,6 +19,7 @@ import {
 import {
   resolveSession,
   writeSessionMessage,
+  writeSessionRouting,
   initSessionFolder,
   sessionDir,
   inboundDbPath,
@@ -26,7 +27,7 @@ import {
   readOutboxFiles,
   clearOutbox,
 } from './session-manager.js';
-import { getSession, findSession } from './db/sessions.js';
+import { getSession, findSession, findSessionByAgentGroup } from './db/sessions.js';
 import type { InboundEvent } from './channels/adapter.js';
 
 // Mock container runner to prevent actual Docker spawning
@@ -595,6 +596,304 @@ describe('router', () => {
   });
 });
 
+describe('routing metadata preservation', () => {
+  beforeEach(() => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Test Agent',
+      folder: 'test-agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroup({
+      id: 'mg-1',
+      channel_type: 'discord',
+      platform_id: 'chan-123',
+      name: 'General',
+      is_group: 1,
+      unknown_sender_policy: 'public',
+      created_at: now(),
+    });
+    createMessagingGroupAgent({
+      id: 'mga-1',
+      messaging_group_id: 'mg-1',
+      agent_group_id: 'ag-1',
+      engage_mode: 'pattern',
+      engage_pattern: '.',
+      sender_scope: 'all',
+      ignored_message_policy: 'drop',
+      session_mode: 'shared',
+      priority: 0,
+      created_at: now(),
+    });
+  });
+
+  it('routed message carries platformId, channelType, threadId on the messages_in row', async () => {
+    const { routeInbound } = await import('./router.js');
+
+    await routeInbound({
+      channelType: 'discord',
+      platformId: 'chan-123',
+      threadId: 'thread-42',
+      message: { id: 'msg-r1', kind: 'chat', content: JSON.stringify({ sender: 'A', text: 'hi' }), timestamp: now() },
+    });
+
+    const session = findSession('mg-1', null);
+    const db = new Database(inboundDbPath('ag-1', session!.id));
+    const row = db.prepare('SELECT platform_id, channel_type, thread_id FROM messages_in WHERE id LIKE ?').get('msg-r1%') as {
+      platform_id: string | null;
+      channel_type: string | null;
+      thread_id: string | null;
+    };
+    db.close();
+
+    expect(row.platform_id).toBe('chan-123');
+    expect(row.channel_type).toBe('discord');
+    expect(row.thread_id).toBe('thread-42');
+  });
+
+  it('fan-out gives each agent its own routing, not leaked from sibling', async () => {
+    const { routeInbound } = await import('./router.js');
+
+    createAgentGroup({
+      id: 'ag-2',
+      name: 'Agent Two',
+      folder: 'agent-two',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroupAgent({
+      id: 'mga-2',
+      messaging_group_id: 'mg-1',
+      agent_group_id: 'ag-2',
+      engage_mode: 'pattern',
+      engage_pattern: '.',
+      sender_scope: 'all',
+      ignored_message_policy: 'drop',
+      session_mode: 'shared',
+      priority: 0,
+      created_at: now(),
+    });
+
+    await routeInbound({
+      channelType: 'discord',
+      platformId: 'chan-123',
+      threadId: 'thread-fanout',
+      message: { id: 'msg-fo', kind: 'chat', content: JSON.stringify({ text: 'fan' }), timestamp: now() },
+    });
+
+    // Both agents should have the message with correct routing
+    const { getSessionsByAgentGroup } = await import('./db/sessions.js');
+    for (const agId of ['ag-1', 'ag-2']) {
+      const sessions = getSessionsByAgentGroup(agId);
+      expect(sessions).toHaveLength(1);
+      const db = new Database(inboundDbPath(agId, sessions[0].id));
+      const row = db.prepare('SELECT platform_id, channel_type, thread_id FROM messages_in LIMIT 1').get() as {
+        platform_id: string | null;
+        channel_type: string | null;
+        thread_id: string | null;
+      };
+      db.close();
+      expect(row.platform_id).toBe('chan-123');
+      expect(row.channel_type).toBe('discord');
+      expect(row.thread_id).toBe('thread-fanout');
+    }
+  });
+});
+
+describe('writeSessionRouting', () => {
+  it('populates session_routing from the messaging group', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroup({
+      id: 'mg-1',
+      channel_type: 'telegram',
+      platform_id: 'tg:12345',
+      name: 'Chat',
+      is_group: 0,
+      unknown_sender_policy: 'public',
+      created_at: now(),
+    });
+
+    const { session } = resolveSession('ag-1', 'mg-1', null, 'shared');
+    writeSessionRouting('ag-1', session.id);
+
+    const db = new Database(inboundDbPath('ag-1', session.id));
+    const row = db.prepare('SELECT channel_type, platform_id, thread_id FROM session_routing WHERE id = 1').get() as {
+      channel_type: string | null;
+      platform_id: string | null;
+      thread_id: string | null;
+    } | undefined;
+    db.close();
+
+    expect(row).toBeDefined();
+    expect(row!.channel_type).toBe('telegram');
+    expect(row!.platform_id).toBe('tg:12345');
+    expect(row!.thread_id).toBeNull();
+  });
+
+  it('writes null routing for agent-shared session (no messaging group)', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+
+    const { session } = resolveSession('ag-1', null, null, 'agent-shared');
+    writeSessionRouting('ag-1', session.id);
+
+    const db = new Database(inboundDbPath('ag-1', session.id));
+    const row = db.prepare('SELECT channel_type, platform_id, thread_id FROM session_routing WHERE id = 1').get() as {
+      channel_type: string | null;
+      platform_id: string | null;
+      thread_id: string | null;
+    } | undefined;
+    db.close();
+
+    expect(row).toBeDefined();
+    expect(row!.channel_type).toBeNull();
+    expect(row!.platform_id).toBeNull();
+    expect(row!.thread_id).toBeNull();
+  });
+
+  it('includes thread_id from per-thread session', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroup({
+      id: 'mg-1',
+      channel_type: 'discord',
+      platform_id: 'chan-123',
+      name: 'General',
+      is_group: 1,
+      unknown_sender_policy: 'public',
+      created_at: now(),
+    });
+
+    const { session } = resolveSession('ag-1', 'mg-1', 'thread-77', 'per-thread');
+    writeSessionRouting('ag-1', session.id);
+
+    const db = new Database(inboundDbPath('ag-1', session.id));
+    const row = db.prepare('SELECT channel_type, platform_id, thread_id FROM session_routing WHERE id = 1').get() as {
+      channel_type: string | null;
+      platform_id: string | null;
+      thread_id: string | null;
+    } | undefined;
+    db.close();
+
+    expect(row).toBeDefined();
+    expect(row!.channel_type).toBe('discord');
+    expect(row!.platform_id).toBe('chan-123');
+    expect(row!.thread_id).toBe('thread-77');
+  });
+});
+
+describe('agent-shared session resolution', () => {
+  it('resolves to the same session on repeated calls', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+
+    const { session: s1, created: c1 } = resolveSession('ag-1', null, null, 'agent-shared');
+    const { session: s2, created: c2 } = resolveSession('ag-1', null, null, 'agent-shared');
+
+    expect(c1).toBe(true);
+    expect(c2).toBe(false);
+    expect(s1.id).toBe(s2.id);
+  });
+
+  it('agent-shared session has null messaging_group_id', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+
+    const { session } = resolveSession('ag-1', null, null, 'agent-shared');
+    expect(session.messaging_group_id).toBeNull();
+  });
+
+  // BUG (#2332): agent-shared resolveSession reuses an existing channel-bound
+  // session via findSessionByAgentGroup instead of creating a dedicated
+  // agent-shared session. The two cannot coexist today — the agent-shared
+  // call finds the channel session and returns it. This test documents the
+  // current (broken) behavior; fixing #2332 should make it pass as written.
+  it.skip('agent-shared and channel-bound sessions coexist for the same agent group', () => {
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroup({
+      id: 'mg-1',
+      channel_type: 'discord',
+      platform_id: 'chan-123',
+      name: 'General',
+      is_group: 1,
+      unknown_sender_policy: 'public',
+      created_at: now(),
+    });
+
+    const { session: shared } = resolveSession('ag-1', 'mg-1', null, 'shared');
+    const { session: agentShared } = resolveSession('ag-1', null, null, 'agent-shared');
+
+    expect(shared.id).not.toBe(agentShared.id);
+    expect(shared.messaging_group_id).toBe('mg-1');
+    expect(agentShared.messaging_group_id).toBeNull();
+  });
+
+  it('findSessionByAgentGroup returns existing channel-bound session (bug #2332)', () => {
+    // Documents the current behavior: findSessionByAgentGroup doesn't
+    // distinguish agent-shared from channel-bound. When a channel session
+    // exists, agent-shared resolution reuses it instead of creating a
+    // separate session. This is the root cause of A2A misrouting.
+    createAgentGroup({
+      id: 'ag-1',
+      name: 'Agent',
+      folder: 'agent',
+      agent_provider: null,
+      created_at: now(),
+    });
+    createMessagingGroup({
+      id: 'mg-1',
+      channel_type: 'discord',
+      platform_id: 'chan-123',
+      name: 'General',
+      is_group: 1,
+      unknown_sender_policy: 'public',
+      created_at: now(),
+    });
+
+    const { session: channelSession } = resolveSession('ag-1', 'mg-1', null, 'shared');
+    const found = findSessionByAgentGroup('ag-1');
+
+    // Bug: picks the channel session — an agent-shared call would get this
+    // instead of a dedicated session.
+    expect(found).toBeDefined();
+    expect(found!.id).toBe(channelSession.id);
+    expect(found!.messaging_group_id).toBe('mg-1'); // should be null for agent-shared
+  });
+});
+
 describe('delivery', () => {
   it('should detect undelivered messages in outbound DB', () => {
     createAgentGroup({