diff --git a/v2/src/lib/adapters/btmsg-bridge.test.ts b/v2/src/lib/adapters/btmsg-bridge.test.ts
index e92bc11..72c7ba7 100644
--- a/v2/src/lib/adapters/btmsg-bridge.test.ts
+++ b/v2/src/lib/adapters/btmsg-bridge.test.ts
@@ -29,6 +29,7 @@ import {
   type BtmsgChannel,
   type BtmsgChannelMessage,
 } from './btmsg-bridge';
+import { GroupId, AgentId } from '../types/ids';
 
 beforeEach(() => {
   vi.clearAllMocks();
@@ -42,10 +43,10 @@ describe('btmsg-bridge', () => {
   describe('BtmsgAgent camelCase fields', () => {
     it('receives camelCase fields from Rust backend', async () => {
       const agent: BtmsgAgent = {
-        id: 'a1',
+        id: AgentId('a1'),
         name: 'Coder',
         role: 'developer',
-        groupId: 'g1',       // was: group_id
+        groupId: GroupId('g1'),       // was: group_id
         tier: 1,
         model: 'claude-4',
         status: 'active',
@@ -53,7 +54,7 @@ describe('btmsg-bridge', () => {
       };
       mockInvoke.mockResolvedValue([agent]);
 
-      const result = await getGroupAgents('g1');
+      const result = await getGroupAgents(GroupId('g1'));
 
       expect(result).toHaveLength(1);
       expect(result[0].groupId).toBe('g1');
@@ -65,7 +66,7 @@ describe('btmsg-bridge', () => {
 
     it('invokes btmsg_get_agents with groupId', async () => {
       mockInvoke.mockResolvedValue([]);
-      await getGroupAgents('g1');
+      await getGroupAgents(GroupId('g1'));
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_get_agents', { groupId: 'g1' });
     });
   });
@@ -74,8 +75,8 @@ describe('btmsg-bridge', () => {
     it('receives camelCase fields from Rust backend', async () => {
       const msg: BtmsgMessage = {
         id: 'm1',
-        fromAgent: 'a1',      // was: from_agent
-        toAgent: 'a2',        // was: to_agent
+        fromAgent: AgentId('a1'),      // was: from_agent
+        toAgent: AgentId('a2'),        // was: to_agent
         content: 'hello',
         read: false,
         replyTo: null,         // was: reply_to
@@ -85,7 +86,7 @@ describe('btmsg-bridge', () => {
       };
       mockInvoke.mockResolvedValue([msg]);
 
-      const result = await getUnreadMessages('a2');
+      const result = await getUnreadMessages(AgentId('a2'));
 
       expect(result[0].fromAgent).toBe('a1');
       expect(result[0].toAgent).toBe('a2');
@@ -100,8 +101,8 @@ describe('btmsg-bridge', () => {
     it('receives camelCase fields including recipient info', async () => {
       const feed: BtmsgFeedMessage = {
         id: 'm1',
-        fromAgent: 'a1',
-        toAgent: 'a2',
+        fromAgent: AgentId('a1'),
+        toAgent: AgentId('a2'),
         content: 'review this',
         createdAt: '2026-01-01',
         replyTo: null,
@@ -112,7 +113,7 @@ describe('btmsg-bridge', () => {
       };
       mockInvoke.mockResolvedValue([feed]);
 
-      const result = await getAllFeed('g1');
+      const result = await getAllFeed(GroupId('g1'));
 
       expect(result[0].senderName).toBe('Coder');
       expect(result[0].recipientName).toBe('Reviewer');
@@ -125,14 +126,14 @@ describe('btmsg-bridge', () => {
       const channel: BtmsgChannel = {
         id: 'ch1',
         name: 'general',
-        groupId: 'g1',        // was: group_id
-        createdBy: 'admin',   // was: created_by
+        groupId: GroupId('g1'),        // was: group_id
+        createdBy: AgentId('admin'),   // was: created_by
         memberCount: 5,       // was: member_count
         createdAt: '2026-01-01',
       };
       mockInvoke.mockResolvedValue([channel]);
 
-      const result = await getChannels('g1');
+      const result = await getChannels(GroupId('g1'));
 
       expect(result[0].groupId).toBe('g1');
       expect(result[0].createdBy).toBe('admin');
@@ -145,7 +146,7 @@ describe('btmsg-bridge', () => {
       const msg: BtmsgChannelMessage = {
         id: 'cm1',
         channelId: 'ch1',     // was: channel_id
-        fromAgent: 'a1',
+        fromAgent: AgentId('a1'),
         content: 'hello',
         createdAt: '2026-01-01',
         senderName: 'Coder',
@@ -166,65 +167,65 @@ describe('btmsg-bridge', () => {
   describe('IPC commands', () => {
     it('getUnreadCount invokes btmsg_unread_count', async () => {
       mockInvoke.mockResolvedValue(5);
-      const result = await getUnreadCount('a1');
+      const result = await getUnreadCount(AgentId('a1'));
       expect(result).toBe(5);
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_unread_count', { agentId: 'a1' });
     });
 
     it('getHistory invokes btmsg_history', async () => {
       mockInvoke.mockResolvedValue([]);
-      await getHistory('a1', 'a2', 50);
+      await getHistory(AgentId('a1'), AgentId('a2'), 50);
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_history', { agentId: 'a1', otherId: 'a2', limit: 50 });
     });
 
     it('getHistory defaults limit to 20', async () => {
       mockInvoke.mockResolvedValue([]);
-      await getHistory('a1', 'a2');
+      await getHistory(AgentId('a1'), AgentId('a2'));
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_history', { agentId: 'a1', otherId: 'a2', limit: 20 });
     });
 
     it('sendMessage invokes btmsg_send', async () => {
       mockInvoke.mockResolvedValue('msg-id');
-      const result = await sendMessage('a1', 'a2', 'hello');
+      const result = await sendMessage(AgentId('a1'), AgentId('a2'), 'hello');
       expect(result).toBe('msg-id');
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_send', { fromAgent: 'a1', toAgent: 'a2', content: 'hello' });
     });
 
     it('setAgentStatus invokes btmsg_set_status', async () => {
       mockInvoke.mockResolvedValue(undefined);
-      await setAgentStatus('a1', 'active');
+      await setAgentStatus(AgentId('a1'), 'active');
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_set_status', { agentId: 'a1', status: 'active' });
     });
 
     it('ensureAdmin invokes btmsg_ensure_admin', async () => {
       mockInvoke.mockResolvedValue(undefined);
-      await ensureAdmin('g1');
+      await ensureAdmin(GroupId('g1'));
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_ensure_admin', { groupId: 'g1' });
     });
 
     it('markRead invokes btmsg_mark_read', async () => {
       mockInvoke.mockResolvedValue(undefined);
-      await markRead('a2', 'a1');
+      await markRead(AgentId('a2'), AgentId('a1'));
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_mark_read', { readerId: 'a2', senderId: 'a1' });
     });
 
     it('sendChannelMessage invokes btmsg_channel_send', async () => {
       mockInvoke.mockResolvedValue('cm-id');
-      const result = await sendChannelMessage('ch1', 'a1', 'hello channel');
+      const result = await sendChannelMessage('ch1', AgentId('a1'), 'hello channel');
       expect(result).toBe('cm-id');
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_channel_send', { channelId: 'ch1', fromAgent: 'a1', content: 'hello channel' });
     });
 
     it('createChannel invokes btmsg_create_channel', async () => {
       mockInvoke.mockResolvedValue('ch-id');
-      const result = await createChannel('general', 'g1', 'admin');
+      const result = await createChannel('general', GroupId('g1'), AgentId('admin'));
       expect(result).toBe('ch-id');
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_create_channel', { name: 'general', groupId: 'g1', createdBy: 'admin' });
     });
 
     it('addChannelMember invokes btmsg_add_channel_member', async () => {
       mockInvoke.mockResolvedValue(undefined);
-      await addChannelMember('ch1', 'a1');
+      await addChannelMember('ch1', AgentId('a1'));
       expect(mockInvoke).toHaveBeenCalledWith('btmsg_add_channel_member', { channelId: 'ch1', agentId: 'a1' });
     });
   });
@@ -232,7 +233,7 @@ describe('btmsg-bridge', () => {
   describe('error propagation', () => {
     it('propagates invoke errors', async () => {
       mockInvoke.mockRejectedValue(new Error('btmsg database not found'));
-      await expect(getGroupAgents('g1')).rejects.toThrow('btmsg database not found');
+      await expect(getGroupAgents(GroupId('g1'))).rejects.toThrow('btmsg database not found');
     });
   });
 });
diff --git a/v2/src/lib/adapters/btmsg-bridge.ts b/v2/src/lib/adapters/btmsg-bridge.ts
index 682bf26..b78fdee 100644
--- a/v2/src/lib/adapters/btmsg-bridge.ts
+++ b/v2/src/lib/adapters/btmsg-bridge.ts
@@ -5,12 +5,13 @@
  */
 
 import { invoke } from '@tauri-apps/api/core';
+import type { GroupId, AgentId } from '../types/ids';
 
 export interface BtmsgAgent {
-  id: string;
+  id: AgentId;
   name: string;
   role: string;
-  groupId: string;
+  groupId: GroupId;
   tier: number;
   model: string | null;
   status: string;
@@ -19,8 +20,8 @@ export interface BtmsgAgent {
 
 export interface BtmsgMessage {
   id: string;
-  fromAgent: string;
-  toAgent: string;
+  fromAgent: AgentId;
+  toAgent: AgentId;
   content: string;
   read: boolean;
   replyTo: string | null;
@@ -31,8 +32,8 @@ export interface BtmsgMessage {
 
 export interface BtmsgFeedMessage {
   id: string;
-  fromAgent: string;
-  toAgent: string;
+  fromAgent: AgentId;
+  toAgent: AgentId;
   content: string;
   createdAt: string;
   replyTo: string | null;
@@ -45,8 +46,8 @@ export interface BtmsgFeedMessage {
 export interface BtmsgChannel {
   id: string;
   name: string;
-  groupId: string;
-  createdBy: string;
+  groupId: GroupId;
+  createdBy: AgentId;
   memberCount: number;
   createdAt: string;
 }
@@ -54,7 +55,7 @@ export interface BtmsgChannel {
 export interface BtmsgChannelMessage {
   id: string;
   channelId: string;
-  fromAgent: string;
+  fromAgent: AgentId;
   content: string;
   createdAt: string;
   senderName: string;
@@ -64,70 +65,70 @@ export interface BtmsgChannelMessage {
 /**
  * Get all agents in a group with their unread counts.
  */
-export async function getGroupAgents(groupId: string): Promise<BtmsgAgent[]> {
+export async function getGroupAgents(groupId: GroupId): Promise<BtmsgAgent[]> {
   return invoke('btmsg_get_agents', { groupId });
 }
 
 /**
  * Get unread message count for an agent.
  */
-export async function getUnreadCount(agentId: string): Promise<number> {
+export async function getUnreadCount(agentId: AgentId): Promise<number> {
   return invoke('btmsg_unread_count', { agentId });
 }
 
 /**
  * Get unread messages for an agent.
  */
-export async function getUnreadMessages(agentId: string): Promise<BtmsgMessage[]> {
+export async function getUnreadMessages(agentId: AgentId): Promise<BtmsgMessage[]> {
   return invoke('btmsg_unread_messages', { agentId });
 }
 
 /**
  * Get conversation history between two agents.
  */
-export async function getHistory(agentId: string, otherId: string, limit: number = 20): Promise<BtmsgMessage[]> {
+export async function getHistory(agentId: AgentId, otherId: AgentId, limit: number = 20): Promise<BtmsgMessage[]> {
   return invoke('btmsg_history', { agentId, otherId, limit });
 }
 
 /**
  * Send a message from one agent to another.
  */
-export async function sendMessage(fromAgent: string, toAgent: string, content: string): Promise<string> {
+export async function sendMessage(fromAgent: AgentId, toAgent: AgentId, content: string): Promise<string> {
   return invoke('btmsg_send', { fromAgent, toAgent, content });
 }
 
 /**
  * Update agent status (active/sleeping/stopped).
  */
-export async function setAgentStatus(agentId: string, status: string): Promise<void> {
+export async function setAgentStatus(agentId: AgentId, status: string): Promise<void> {
   return invoke('btmsg_set_status', { agentId, status });
 }
 
 /**
  * Ensure admin agent exists with contacts to all agents.
  */
-export async function ensureAdmin(groupId: string): Promise<void> {
+export async function ensureAdmin(groupId: GroupId): Promise<void> {
   return invoke('btmsg_ensure_admin', { groupId });
 }
 
 /**
  * Get all messages in group (admin global feed).
  */
-export async function getAllFeed(groupId: string, limit: number = 100): Promise<BtmsgFeedMessage[]> {
+export async function getAllFeed(groupId: GroupId, limit: number = 100): Promise<BtmsgFeedMessage[]> {
   return invoke('btmsg_all_feed', { groupId, limit });
 }
 
 /**
  * Mark all messages from sender to reader as read.
  */
-export async function markRead(readerId: string, senderId: string): Promise<void> {
+export async function markRead(readerId: AgentId, senderId: AgentId): Promise<void> {
   return invoke('btmsg_mark_read', { readerId, senderId });
 }
 
 /**
  * Get channels in a group.
  */
-export async function getChannels(groupId: string): Promise<BtmsgChannel[]> {
+export async function getChannels(groupId: GroupId): Promise<BtmsgChannel[]> {
   return invoke('btmsg_get_channels', { groupId });
 }
 
@@ -141,20 +142,20 @@ export async function getChannelMessages(channelId: string, limit: number = 100)
 /**
  * Send a message to a channel.
  */
-export async function sendChannelMessage(channelId: string, fromAgent: string, content: string): Promise<string> {
+export async function sendChannelMessage(channelId: string, fromAgent: AgentId, content: string): Promise<string> {
   return invoke('btmsg_channel_send', { channelId, fromAgent, content });
 }
 
 /**
  * Create a new channel.
  */
-export async function createChannel(name: string, groupId: string, createdBy: string): Promise<string> {
+export async function createChannel(name: string, groupId: GroupId, createdBy: AgentId): Promise<string> {
   return invoke('btmsg_create_channel', { name, groupId, createdBy });
 }
 
 /**
  * Add a member to a channel.
  */
-export async function addChannelMember(channelId: string, agentId: string): Promise<void> {
+export async function addChannelMember(channelId: string, agentId: AgentId): Promise<void> {
   return invoke('btmsg_add_channel_member', { channelId, agentId });
 }
diff --git a/v2/src/lib/adapters/bttask-bridge.test.ts b/v2/src/lib/adapters/bttask-bridge.test.ts
index 779d127..9003ad6 100644
--- a/v2/src/lib/adapters/bttask-bridge.test.ts
+++ b/v2/src/lib/adapters/bttask-bridge.test.ts
@@ -18,6 +18,7 @@ import {
   type Task,
   type TaskComment,
 } from './bttask-bridge';
+import { GroupId, AgentId } from '../types/ids';
 
 beforeEach(() => {
   vi.clearAllMocks();
@@ -34,9 +35,9 @@ describe('bttask-bridge', () => {
         description: 'Critical fix',
         status: 'progress',
         priority: 'high',
-        assignedTo: 'a1',        // was: assigned_to
-        createdBy: 'admin',      // was: created_by
-        groupId: 'g1',           // was: group_id
+        assignedTo: AgentId('a1'),        // was: assigned_to
+        createdBy: AgentId('admin'),      // was: created_by
+        groupId: GroupId('g1'),           // was: group_id
         parentTaskId: null,      // was: parent_task_id
         sortOrder: 1,            // was: sort_order
         createdAt: '2026-01-01', // was: created_at
@@ -44,7 +45,7 @@ describe('bttask-bridge', () => {
       };
       mockInvoke.mockResolvedValue([task]);
 
-      const result = await listTasks('g1');
+      const result = await listTasks(GroupId('g1'));
 
       expect(result).toHaveLength(1);
       expect(result[0].assignedTo).toBe('a1');
@@ -64,7 +65,7 @@ describe('bttask-bridge', () => {
       const comment: TaskComment = {
         id: 'c1',
         taskId: 't1',           // was: task_id
-        agentId: 'a1',          // was: agent_id
+        agentId: AgentId('a1'),          // was: agent_id
         content: 'Working on it',
         createdAt: '2026-01-01',
       };
@@ -84,7 +85,7 @@ describe('bttask-bridge', () => {
   describe('IPC commands', () => {
     it('listTasks invokes bttask_list', async () => {
       mockInvoke.mockResolvedValue([]);
-      await listTasks('g1');
+      await listTasks(GroupId('g1'));
       expect(mockInvoke).toHaveBeenCalledWith('bttask_list', { groupId: 'g1' });
     });
 
@@ -102,14 +103,14 @@ describe('bttask-bridge', () => {
 
     it('addTaskComment invokes bttask_add_comment', async () => {
       mockInvoke.mockResolvedValue('c-id');
-      const result = await addTaskComment('t1', 'a1', 'Done!');
+      const result = await addTaskComment('t1', AgentId('a1'), 'Done!');
       expect(result).toBe('c-id');
       expect(mockInvoke).toHaveBeenCalledWith('bttask_add_comment', { taskId: 't1', agentId: 'a1', content: 'Done!' });
     });
 
     it('createTask invokes bttask_create with all fields', async () => {
       mockInvoke.mockResolvedValue('t-id');
-      const result = await createTask('Fix bug', 'desc', 'high', 'g1', 'admin', 'a1');
+      const result = await createTask('Fix bug', 'desc', 'high', GroupId('g1'), AgentId('admin'), AgentId('a1'));
       expect(result).toBe('t-id');
       expect(mockInvoke).toHaveBeenCalledWith('bttask_create', {
         title: 'Fix bug',
@@ -123,7 +124,7 @@ describe('bttask-bridge', () => {
 
     it('createTask invokes bttask_create without assignedTo', async () => {
       mockInvoke.mockResolvedValue('t-id');
-      await createTask('Add tests', '', 'medium', 'g1', 'a1');
+      await createTask('Add tests', '', 'medium', GroupId('g1'), AgentId('a1'));
       expect(mockInvoke).toHaveBeenCalledWith('bttask_create', {
         title: 'Add tests',
         description: '',
@@ -144,7 +145,7 @@ describe('bttask-bridge', () => {
   describe('error propagation', () => {
     it('propagates invoke errors', async () => {
       mockInvoke.mockRejectedValue(new Error('btmsg database not found'));
-      await expect(listTasks('g1')).rejects.toThrow('btmsg database not found');
+      await expect(listTasks(GroupId('g1'))).rejects.toThrow('btmsg database not found');
     });
   });
 });
diff --git a/v2/src/lib/adapters/bttask-bridge.ts b/v2/src/lib/adapters/bttask-bridge.ts
index 7146b8f..d0ce775 100644
--- a/v2/src/lib/adapters/bttask-bridge.ts
+++ b/v2/src/lib/adapters/bttask-bridge.ts
@@ -1,6 +1,7 @@
 // bttask Bridge — Tauri IPC adapter for task board
 
 import { invoke } from '@tauri-apps/api/core';
+import type { GroupId, AgentId } from '../types/ids';
 
 export interface Task {
   id: string;
@@ -8,9 +9,9 @@ export interface Task {
   description: string;
   status: 'todo' | 'progress' | 'review' | 'done' | 'blocked';
   priority: 'low' | 'medium' | 'high' | 'critical';
-  assignedTo: string | null;
-  createdBy: string;
-  groupId: string;
+  assignedTo: AgentId | null;
+  createdBy: AgentId;
+  groupId: GroupId;
   parentTaskId: string | null;
   sortOrder: number;
   createdAt: string;
@@ -20,12 +21,12 @@ export interface Task {
 export interface TaskComment {
   id: string;
   taskId: string;
-  agentId: string;
+  agentId: AgentId;
   content: string;
   createdAt: string;
 }
 
-export async function listTasks(groupId: string): Promise<Task[]> {
+export async function listTasks(groupId: GroupId): Promise<Task[]> {
   return invoke<Task[]>('bttask_list', { groupId });
 }
 
@@ -37,7 +38,7 @@ export async function updateTaskStatus(taskId: string, status: string): Promise<
   return invoke('bttask_update_status', { taskId, status });
 }
 
-export async function addTaskComment(taskId: string, agentId: string, content: string): Promise<string> {
+export async function addTaskComment(taskId: string, agentId: AgentId, content: string): Promise<string> {
   return invoke<string>('bttask_add_comment', { taskId, agentId, content });
 }
 
@@ -45,9 +46,9 @@ export async function createTask(
   title: string,
   description: string,
   priority: string,
-  groupId: string,
-  createdBy: string,
-  assignedTo?: string,
+  groupId: GroupId,
+  createdBy: AgentId,
+  assignedTo?: AgentId,
 ): Promise<string> {
   return invoke<string>('bttask_create', { title, description, priority, groupId, createdBy, assignedTo });
 }
diff --git a/v2/src/lib/adapters/groups-bridge.ts b/v2/src/lib/adapters/groups-bridge.ts
index 1782563..72551f9 100644
--- a/v2/src/lib/adapters/groups-bridge.ts
+++ b/v2/src/lib/adapters/groups-bridge.ts
@@ -1,5 +1,6 @@
 import { invoke } from '@tauri-apps/api/core';
 import type { GroupsFile, ProjectConfig, GroupConfig } from '../types/groups';
+import type { SessionId, ProjectId } from '../types/ids';
 
 export type { GroupsFile, ProjectConfig, GroupConfig };
 
@@ -11,8 +12,8 @@ export interface MdFileEntry {
 
 export interface AgentMessageRecord {
   id: number;
-  session_id: string;
-  project_id: string;
+  session_id: SessionId;
+  project_id: ProjectId;
   sdk_session_id: string | null;
   message_type: string;
   content: string;
@@ -21,8 +22,8 @@ export interface AgentMessageRecord {
 }
 
 export interface ProjectAgentState {
-  project_id: string;
-  last_session_id: string;
+  project_id: ProjectId;
+  last_session_id: SessionId;
   sdk_session_id: string | null;
   status: string;
   cost_usd: number;
@@ -51,8 +52,8 @@ export async function discoverMarkdownFiles(cwd: string): Promise<MdFileEntry[]>
 // --- Agent message persistence ---
 
 export async function saveAgentMessages(
-  sessionId: string,
-  projectId: string,
+  sessionId: SessionId,
+  projectId: ProjectId,
   sdkSessionId: string | undefined,
   messages: AgentMessageRecord[],
 ): Promise<void> {
@@ -64,7 +65,7 @@ export async function saveAgentMessages(
   });
 }
 
-export async function loadAgentMessages(projectId: string): Promise<AgentMessageRecord[]> {
+export async function loadAgentMessages(projectId: ProjectId): Promise<AgentMessageRecord[]> {
   return invoke('agent_messages_load', { projectId });
 }
 
@@ -74,7 +75,7 @@ export async function saveProjectAgentState(state: ProjectAgentState): Promise<v
   return invoke('project_agent_state_save', { state });
 }
 
-export async function loadProjectAgentState(projectId: string): Promise<ProjectAgentState | null> {
+export async function loadProjectAgentState(projectId: ProjectId): Promise<ProjectAgentState | null> {
   return invoke('project_agent_state_load', { projectId });
 }
 
@@ -82,8 +83,8 @@ export async function loadProjectAgentState(projectId: string): Promise<ProjectA
 
 export interface SessionMetric {
   id: number;
-  project_id: string;
-  session_id: string;
+  project_id: ProjectId;
+  session_id: SessionId;
   start_time: number;
   end_time: number;
   peak_tokens: number;
@@ -99,7 +100,7 @@ export async function saveSessionMetric(metric: Omit<SessionMetric, 'id'>): Prom
   return invoke('session_metric_save', { metric: { id: 0, ...metric } });
 }
 
-export async function loadSessionMetrics(projectId: string, limit = 20): Promise<SessionMetric[]> {
+export async function loadSessionMetrics(projectId: ProjectId, limit = 20): Promise<SessionMetric[]> {
   return invoke('session_metrics_load', { projectId, limit });
 }