diff --git a/tests/test_task_cancel.py b/tests/test_task_cancel.py
deleted file mode 100644
index 27a2d73..0000000
--- a/tests/test_task_cancel.py
+++ /dev/null
@@ -1,167 +0,0 @@
-"""Tests for /stop task cancellation."""
-
-from __future__ import annotations
-
-import asyncio
-from unittest.mock import AsyncMock, MagicMock, patch
-
-import pytest
-
-
-def _make_loop():
-    """Create a minimal AgentLoop with mocked dependencies."""
-    from nanobot.agent.loop import AgentLoop
-    from nanobot.bus.queue import MessageBus
-
-    bus = MessageBus()
-    provider = MagicMock()
-    provider.get_default_model.return_value = "test-model"
-    workspace = MagicMock()
-    workspace.__truediv__ = MagicMock(return_value=MagicMock())
-
-    with patch("nanobot.agent.loop.ContextBuilder"), \
-         patch("nanobot.agent.loop.SessionManager"), \
-         patch("nanobot.agent.loop.SubagentManager") as MockSubMgr:
-        MockSubMgr.return_value.cancel_by_session = AsyncMock(return_value=0)
-        loop = AgentLoop(bus=bus, provider=provider, workspace=workspace)
-    return loop, bus
-
-
-class TestHandleStop:
-    @pytest.mark.asyncio
-    async def test_stop_no_active_task(self):
-        from nanobot.bus.events import InboundMessage
-
-        loop, bus = _make_loop()
-        msg = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="/stop")
-        await loop._handle_stop(msg)
-        out = await asyncio.wait_for(bus.consume_outbound(), timeout=1.0)
-        assert "No active task" in out.content
-
-    @pytest.mark.asyncio
-    async def test_stop_cancels_active_task(self):
-        from nanobot.bus.events import InboundMessage
-
-        loop, bus = _make_loop()
-        cancelled = asyncio.Event()
-
-        async def slow_task():
-            try:
-                await asyncio.sleep(60)
-            except asyncio.CancelledError:
-                cancelled.set()
-                raise
-
-        task = asyncio.create_task(slow_task())
-        await asyncio.sleep(0)
-        loop._active_tasks["test:c1"] = [task]
-
-        msg = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="/stop")
-        await loop._handle_stop(msg)
-
-        assert cancelled.is_set()
-        out = await asyncio.wait_for(bus.consume_outbound(), timeout=1.0)
-        assert "stopped" in out.content.lower()
-
-    @pytest.mark.asyncio
-    async def test_stop_cancels_multiple_tasks(self):
-        from nanobot.bus.events import InboundMessage
-
-        loop, bus = _make_loop()
-        events = [asyncio.Event(), asyncio.Event()]
-
-        async def slow(idx):
-            try:
-                await asyncio.sleep(60)
-            except asyncio.CancelledError:
-                events[idx].set()
-                raise
-
-        tasks = [asyncio.create_task(slow(i)) for i in range(2)]
-        await asyncio.sleep(0)
-        loop._active_tasks["test:c1"] = tasks
-
-        msg = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="/stop")
-        await loop._handle_stop(msg)
-
-        assert all(e.is_set() for e in events)
-        out = await asyncio.wait_for(bus.consume_outbound(), timeout=1.0)
-        assert "2 task" in out.content
-
-
-class TestDispatch:
-    @pytest.mark.asyncio
-    async def test_dispatch_processes_and_publishes(self):
-        from nanobot.bus.events import InboundMessage, OutboundMessage
-
-        loop, bus = _make_loop()
-        msg = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="hello")
-        loop._process_message = AsyncMock(
-            return_value=OutboundMessage(channel="test", chat_id="c1", content="hi")
-        )
-        await loop._dispatch(msg)
-        out = await asyncio.wait_for(bus.consume_outbound(), timeout=1.0)
-        assert out.content == "hi"
-
-    @pytest.mark.asyncio
-    async def test_processing_lock_serializes(self):
-        from nanobot.bus.events import InboundMessage, OutboundMessage
-
-        loop, bus = _make_loop()
-        order = []
-
-        async def mock_process(m, **kwargs):
-            order.append(f"start-{m.content}")
-            await asyncio.sleep(0.05)
-            order.append(f"end-{m.content}")
-            return OutboundMessage(channel="test", chat_id="c1", content=m.content)
-
-        loop._process_message = mock_process
-        msg1 = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="a")
-        msg2 = InboundMessage(channel="test", sender_id="u1", chat_id="c1", content="b")
-
-        t1 = asyncio.create_task(loop._dispatch(msg1))
-        t2 = asyncio.create_task(loop._dispatch(msg2))
-        await asyncio.gather(t1, t2)
-        assert order == ["start-a", "end-a", "start-b", "end-b"]
-
-
-class TestSubagentCancellation:
-    @pytest.mark.asyncio
-    async def test_cancel_by_session(self):
-        from nanobot.agent.subagent import SubagentManager
-        from nanobot.bus.queue import MessageBus
-
-        bus = MessageBus()
-        provider = MagicMock()
-        provider.get_default_model.return_value = "test-model"
-        mgr = SubagentManager(provider=provider, workspace=MagicMock(), bus=bus)
-
-        cancelled = asyncio.Event()
-
-        async def slow():
-            try:
-                await asyncio.sleep(60)
-            except asyncio.CancelledError:
-                cancelled.set()
-                raise
-
-        task = asyncio.create_task(slow())
-        await asyncio.sleep(0)
-        mgr._running_tasks["sub-1"] = task
-        mgr._session_tasks["test:c1"] = {"sub-1"}
-
-        count = await mgr.cancel_by_session("test:c1")
-        assert count == 1
-        assert cancelled.is_set()
-
-    @pytest.mark.asyncio
-    async def test_cancel_by_session_no_tasks(self):
-        from nanobot.agent.subagent import SubagentManager
-        from nanobot.bus.queue import MessageBus
-
-        bus = MessageBus()
-        provider = MagicMock()
-        provider.get_default_model.return_value = "test-model"
-        mgr = SubagentManager(provider=provider, workspace=MagicMock(), bus=bus)
-        assert await mgr.cancel_by_session("nonexistent") == 0