diff --git a/packages/iios-messaging-ui/src/hooks/use-messages.test.tsx b/packages/iios-messaging-ui/src/hooks/use-messages.test.tsx
new file mode 100644
index 0000000..f6d0771
--- /dev/null
+++ b/packages/iios-messaging-ui/src/hooks/use-messages.test.tsx
@@ -0,0 +1,160 @@
+import { describe, it, expect, vi } from 'vitest';
+import { renderHook, waitFor, act } from '@testing-library/react';
+import type { ReactNode } from 'react';
+import { MessagingProvider } from '../provider';
+import { MockAdapter } from '../adapters/mock';
+import { useMessages } from './use-messages';
+import type { MessagingAdapter } from '../adapter';
+import type { Message } from '../types';
+
+const wrap = (adapter: MessagingAdapter) =>
+  function Wrapper({ children }: { children: ReactNode }) {
+    return <MessagingProvider adapter={adapter}>{children}</MessagingProvider>;
+  };
+
+describe('useMessages', () => {
+  it('loads history for the thread', async () => {
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(new MockAdapter()) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+    expect(result.current.messages).toHaveLength(1);
+    expect(result.current.messages[0]!.text).toBe('Can you review the Henderson estimate?');
+  });
+
+  // REGRESSION: the CRM inferred actor identity by scanning for a sent message, so
+  // before you had spoken in a thread EVERY message rendered as not-yours.
+  it('marks ownership correctly before the user has sent anything', async () => {
+    const adapter = new MockAdapter();
+    await adapter.send('th_mock_1', 'an earlier message of mine');
+
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.messages).toHaveLength(2));
+
+    // Never sent anything via the hook — ownership still resolves from currentActorId().
+    expect(result.current.messages[0]!.mine).toBe(false); // from pp_sofia
+    expect(result.current.messages[1]!.mine).toBe(true); // from me
+  });
+
+  it('appends an optimistic message immediately on send', async () => {
+    const adapter = new MockAdapter();
+    let release!: () => void;
+    vi.spyOn(adapter, 'send').mockImplementation(
+      () => new Promise((res) => { release = () => res({ id: 'srv_1', actorId: 'me', text: 'hi', at: '2026-07-17T10:00:00.000Z' }); }),
+    );
+
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+
+    act(() => { void result.current.send('hi'); });
+
+    await waitFor(() => expect(result.current.messages).toHaveLength(2));
+    expect(result.current.messages[1]!.pending).toBe(true);
+    expect(result.current.messages[1]!.mine).toBe(true);
+
+    await act(async () => { release(); });
+    await waitFor(() => expect(result.current.messages[1]!.pending).toBeFalsy());
+  });
+
+  it('rolls back the optimistic message and reports error when send fails', async () => {
+    const adapter = new MockAdapter();
+    vi.spyOn(adapter, 'send').mockRejectedValue(new Error('offline'));
+
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+
+    await act(async () => {
+      await expect(result.current.send('doomed')).rejects.toThrow('offline');
+    });
+
+    expect(result.current.messages).toHaveLength(1);
+    expect(result.current.messages.some((m) => m.text === 'doomed')).toBe(false);
+    expect(result.current.error).toBe('offline');
+  });
+
+  it('does not duplicate a message when the transport echoes it back', async () => {
+    const adapter = new MockAdapter();
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+
+    // MockAdapter.send emits a 'message' event AND resolves with the same message.
+    await act(async () => { await result.current.send('echo once'); });
+
+    expect(result.current.messages.filter((m) => m.text === 'echo once')).toHaveLength(1);
+  });
+
+  it('collects typing user ids from subscribe events', async () => {
+    const adapter = new MockAdapter();
+    let emit!: (userId: string) => void;
+    vi.spyOn(adapter, 'subscribe').mockImplementation((_t, cb) => {
+      emit = (userId) => cb({ kind: 'typing', userId });
+      return () => {};
+    });
+
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+
+    act(() => emit('pp_sofia'));
+    expect(result.current.typingUserIds).toEqual(['pp_sofia']);
+  });
+
+  it('unsubscribes on unmount', async () => {
+    const adapter = new MockAdapter();
+    const off = vi.fn();
+    vi.spyOn(adapter, 'subscribe').mockReturnValue(off);
+
+    const { unmount, result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+    await waitFor(() => expect(result.current.loading).toBe(false));
+    unmount();
+
+    expect(off).toHaveBeenCalled();
+  });
+
+  it('keeps a live message that arrives before history resolves', async () => {
+    const adapter = new MockAdapter();
+    let resolveHistory!: (msgs: Message[]) => void;
+    vi.spyOn(adapter, 'history').mockImplementation(
+      () => new Promise<Message[]>((res) => { resolveHistory = res; }),
+    );
+    let emit!: (m: Message) => void;
+    vi.spyOn(adapter, 'subscribe').mockImplementation((_t, cb) => {
+      emit = (m) => cb({ kind: 'message', message: m });
+      return () => {};
+    });
+
+    const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+
+    // A live message arrives while history() is still pending.
+    act(() => emit({ id: 'live_1', actorId: 'pp_sofia', text: 'ping before history', at: '2026-07-17T10:00:00.000Z' }));
+
+    // History resolves afterwards with an older message.
+    await act(async () => {
+      resolveHistory([{ id: 'hist_1', actorId: 'pp_sofia', text: 'older', at: '2026-07-17T09:00:00.000Z' }]);
+    });
+
+    const texts = result.current.messages.map((m) => m.text);
+    expect(texts).toContain('older');
+    expect(texts).toContain('ping before history'); // must NOT be clobbered by history load
+  });
+
+  it('clears a typing indicator after its TTL elapses', async () => {
+    vi.useFakeTimers();
+    try {
+      const adapter = new MockAdapter();
+      let emit!: (userId: string) => void;
+      vi.spyOn(adapter, 'subscribe').mockImplementation((_t, cb) => {
+        emit = (userId) => cb({ kind: 'typing', userId });
+        return () => {};
+      });
+
+      const { result } = renderHook(() => useMessages('th_mock_1'), { wrapper: wrap(adapter) });
+      await act(async () => { await vi.advanceTimersByTimeAsync(0); }); // flush history microtask
+
+      act(() => emit('pp_sofia'));
+      expect(result.current.typingUserIds).toEqual(['pp_sofia']);
+
+      await act(async () => { await vi.advanceTimersByTimeAsync(3600); });
+      expect(result.current.typingUserIds).toEqual([]);
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+});
diff --git a/packages/iios-messaging-ui/src/hooks/use-messages.ts b/packages/iios-messaging-ui/src/hooks/use-messages.ts
new file mode 100644
index 0000000..d50954d
--- /dev/null
+++ b/packages/iios-messaging-ui/src/hooks/use-messages.ts
@@ -0,0 +1,205 @@
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
+import { useAdapter } from '../provider';
+import { isOwnMessage } from '../types';
+import type { Message, SendOpts } from '../types';
+
+const TYPING_TTL_MS = 3500;
+
+export interface UiMessage extends Message {
+  mine: boolean;
+}
+
+export interface MessagesState {
+  messages: UiMessage[];
+  loading: boolean;
+  error: string | null;
+  send: (content: string, opts?: SendOpts) => Promise<void>;
+  react: (messageId: string, emoji: string) => Promise<void>;
+  typingUserIds: string[];
+  seenIds: Set<string>;
+  sendTyping: () => void;
+  canReact: boolean;
+  canUpload: boolean;
+}
+
+let optimisticSeq = 0;
+
+export function useMessages(threadId: string | null): MessagesState {
+  const adapter = useAdapter();
+  const [raw, setRaw] = useState<Message[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+  const [typing, setTyping] = useState<Record<string, number>>({});
+  const [seenIds, setSeenIds] = useState<Set<string>>(new Set());
+
+  const currentActorId = adapter.currentActorId();
+  const actorRef = useRef(currentActorId);
+  actorRef.current = currentActorId;
+
+  // Load history, then subscribe. Reconciliation is by message id, so an echoed
+  // send never duplicates the optimistic row.
+  useEffect(() => {
+    if (!threadId) {
+      setRaw([]);
+      setLoading(false);
+      return;
+    }
+    let alive = true;
+    setLoading(true);
+    setRaw([]);
+    setError(null);
+    setSeenIds(new Set());
+    setTyping({});
+
+    adapter
+      .history(threadId)
+      .then((h) => {
+        if (!alive) return;
+        // Merge, don't clobber: a live message can arrive via subscribe while this
+        // history fetch is still in flight. Blindly setting raw = h would drop it.
+        setRaw((live) => {
+          const histIds = new Set(h.map((m) => m.id));
+          const extras = live.filter((m) => !histIds.has(m.id));
+          return extras.length ? [...h, ...extras] : h;
+        });
+        setError(null);
+      })
+      .catch((e: unknown) => {
+        if (alive) setError(e instanceof Error ? e.message : String(e));
+      })
+      .finally(() => {
+        if (alive) setLoading(false);
+      });
+
+    const off = adapter.subscribe(threadId, (e) => {
+      if (!alive) return;
+      switch (e.kind) {
+        case 'message':
+          setRaw((l) => (l.some((m) => m.id === e.message.id) ? l : [...l, e.message]));
+          break;
+        case 'typing':
+          if (e.userId !== actorRef.current) {
+            setTyping((t) => ({ ...t, [e.userId]: Date.now() + TYPING_TTL_MS }));
+          }
+          break;
+        case 'receipt':
+          // Only the OTHER side reading my message counts as "seen".
+          if (e.actorId !== actorRef.current) {
+            setSeenIds((s) => (s.has(e.messageId) ? s : new Set(s).add(e.messageId)));
+          }
+          break;
+        case 'reaction':
+          setRaw((l) => l.map((m) => (m.id === e.messageId ? { ...m, reactions: e.reactions } : m)));
+          break;
+      }
+    });
+
+    return () => {
+      alive = false;
+      off();
+    };
+  }, [adapter, threadId]);
+
+  const messages: UiMessage[] = useMemo(
+    () => raw.map((m) => ({ ...m, mine: isOwnMessage(m, currentActorId) })),
+    [raw, currentActorId],
+  );
+
+  const send = useCallback(
+    async (content: string, opts?: SendOpts) => {
+      if (!threadId) return;
+      const tempId = `optimistic_${optimisticSeq++}`;
+      const optimistic: Message = {
+        id: tempId,
+        actorId: actorRef.current,
+        text: content,
+        at: new Date().toISOString(),
+        pending: true,
+        reactions: [],
+        ...(opts?.parentInteractionId ? { parentInteractionId: opts.parentInteractionId } : {}),
+        ...(opts?.attachment ? { attachment: opts.attachment } : {}),
+      };
+      setRaw((l) => [...l, optimistic]);
+
+      try {
+        const saved = await adapter.send(threadId, content, opts);
+        setError(null);
+        // Replace the optimistic row with the server's. If the subscribe echo already
+        // added the real message, just drop the optimistic one.
+        setRaw((l) => {
+          const withoutTemp = l.filter((m) => m.id !== tempId);
+          return withoutTemp.some((m) => m.id === saved.id) ? withoutTemp : [...withoutTemp, saved];
+        });
+      } catch (e: unknown) {
+        setRaw((l) => l.filter((m) => m.id !== tempId));
+        setError(e instanceof Error ? e.message : String(e));
+        throw e;
+      }
+    },
+    [adapter, threadId],
+  );
+
+  const react = useCallback(
+    async (messageId: string, emoji: string) => {
+      if (!threadId || !adapter.react) return;
+      await adapter.react(threadId, messageId, emoji);
+    },
+    [adapter, threadId],
+  );
+
+  const sendTyping = useCallback(() => {
+    if (threadId) adapter.sendTyping(threadId);
+  }, [adapter, threadId]);
+
+  // The newest acknowledged (non-pending) message id — what we report as read.
+  const lastReadableId = useMemo(() => {
+    for (let i = raw.length - 1; i >= 0; i--) {
+      if (!raw[i]!.pending) return raw[i]!.id;
+    }
+    return null;
+  }, [raw]);
+
+  // Report my read of the newest message (drives the other side's "seen" tick).
+  // Keyed on the id, not the whole array, so reaction/optimistic churn doesn't re-fire it.
+  useEffect(() => {
+    if (!threadId || !lastReadableId) return;
+    void adapter.markRead(threadId, lastReadableId).catch(() => {});
+  }, [adapter, threadId, lastReadableId]);
+
+  const typingUserIds = useMemo(() => {
+    const now = Date.now();
+    return Object.entries(typing)
+      .filter(([, exp]) => exp > now)
+      .map(([u]) => u);
+  }, [typing]);
+
+  // Expire stale typing entries. Bumping `typing` to a new reference forces the
+  // memo above to recompute with a fresh `now`, dropping entries past their TTL.
+  // (A bump of unrelated state can't do this — the memo is keyed on `typing`, so it
+  // would return its cached array and the indicator would stick forever.)
+  useEffect(() => {
+    if (typingUserIds.length === 0) return;
+    const t = setTimeout(() => setTyping((p) => ({ ...p })), TYPING_TTL_MS);
+    return () => clearTimeout(t);
+  }, [typingUserIds.length, typing]);
+
+  // Only my messages that the other side has read.
+  const seenMine = useMemo(() => {
+    const out = new Set<string>();
+    for (const id of seenIds) if (messages.some((m) => m.id === id && m.mine)) out.add(id);
+    return out;
+  }, [seenIds, messages]);
+
+  return {
+    messages,
+    loading,
+    error,
+    send,
+    react,
+    typingUserIds,
+    seenIds: seenMine,
+    sendTyping,
+    canReact: typeof adapter.react === 'function',
+    canUpload: typeof adapter.upload === 'function',
+  };
+}