diff --git a/readme.md b/readme.md
index 973f713..036f926 100644
--- a/readme.md
+++ b/readme.md
@@ -94,6 +94,10 @@ Reply to a bot message (containing `resume: <uuid>`), or include the resume line
 resume: `019b66fc-64c2-7a71-81cd-081c504cfeb2`
 ```
 
+### Cancel a Run
+
+Reply to a progress message with `/cancel` to stop the running execution.
+
 ## Notes
 
 - **Startup**: Pending updates are drained (ignored) on startup
diff --git a/src/takopi/exec_bridge.py b/src/takopi/exec_bridge.py
index 01dfd39..0eefb8a 100644
--- a/src/takopi/exec_bridge.py
+++ b/src/takopi/exec_bridge.py
@@ -19,11 +19,16 @@ import typer
 
 from . import __version__
 from .config import ConfigError, load_telegram_config
-from .exec_render import ExecProgressRenderer, render_event_cli, render_markdown
+from .exec_render import (
+    ExecProgressRenderer,
+    render_event_cli,
+    render_markdown,
+)
 from .logging import setup_logging
 from .onboarding import check_setup, render_setup_guide
 from .telegram import TelegramClient
 
+
 logger = logging.getLogger(__name__)
 UUID_PATTERN_TEXT = r"\b[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\b"
 UUID_PATTERN = re.compile(UUID_PATTERN_TEXT, re.IGNORECASE)
@@ -277,10 +282,10 @@ class CodexExecRunner:
                         except Exception as e:
                             logger.info("[codex][on_event] callback error: %s", e)
 
-                    if evt.get("type") == "thread.started":
+                    if evt["type"] == "thread.started":
                         found_session = evt.get("thread_id") or found_session
 
-                    if evt.get("type") == "item.completed":
+                    if evt["type"] == "item.completed":
                         item = evt.get("item") or {}
                         if item.get("type") == "agent_message" and isinstance(
                             item.get("text"), str
@@ -291,6 +296,8 @@ class CodexExecRunner:
                 cancelled = True
             finally:
                 if cancelled:
+                    if not stderr_task.done():
+                        stderr_task.cancel()
                     task = cast(asyncio.Task, asyncio.current_task())
                     while task.cancelling():
                         task.uncancel()
@@ -431,6 +438,7 @@ async def _handle_message(
     user_msg_id: int,
     text: str,
     resume_session: str | None,
+    running_tasks: dict[str, asyncio.Task[Any]] | None = None,
     clock: Callable[[], float] = time.monotonic,
     progress_edit_every: float = PROGRESS_EDIT_EVERY_S,
 ) -> None:
@@ -511,12 +519,25 @@ async def _handle_message(
             "[handle] failed to send progress message chat_id=%s: %s", chat_id, e
         )
 
+    exec_task: asyncio.Task[tuple[str, str, bool]] | None = None
+    tracked_session_id: str | None = None
+
     async def on_event(evt: dict[str, Any]) -> None:
-        nonlocal last_edit_at, edit_task, pending_rendered
+        nonlocal last_edit_at, edit_task, pending_rendered, tracked_session_id
         if progress_id is None:
             return
         if not progress_renderer.note_event(evt):
             return
+
+        if (
+            evt["type"] == "thread.started"
+            and running_tasks is not None
+            and exec_task is not None
+        ):
+            tracked_session_id = progress_renderer.resume_session
+            if tracked_session_id:
+                running_tasks[tracked_session_id] = exec_task
+
         now = clock()
         if (now - last_edit_at) < progress_edit_every:
             return
@@ -531,10 +552,16 @@ async def _handle_message(
         pending_rendered = rendered
         edit_task = asyncio.create_task(_edit_progress(md, rendered, entities))
 
+    exec_task = asyncio.create_task(
+        cfg.runner.run_serialized(text, resume_session, on_event=on_event)
+    )
+
+    cancelled = False
     try:
-        session_id, answer, saw_agent_message = await cfg.runner.run_serialized(
-            text, resume_session, on_event=on_event
-        )
+        session_id, answer, saw_agent_message = await exec_task
+    except asyncio.CancelledError:
+        cancelled = True
+        session_id = tracked_session_id or resume_session
     except Exception as e:
         if edit_task is not None:
             await asyncio.gather(edit_task, return_exceptions=True)
@@ -551,11 +578,34 @@ async def _handle_message(
             limit=TELEGRAM_MARKDOWN_LIMIT,
         )
         return
+    finally:
+        if tracked_session_id and running_tasks is not None and exec_task is not None:
+            # Avoid removing a newer task for the same session_id if another run
+            # registered while this one was finishing.
+            if running_tasks.get(tracked_session_id) is exec_task:
+                running_tasks.pop(tracked_session_id, None)
 
     if edit_task is not None:
         await asyncio.gather(edit_task, return_exceptions=True)
 
     elapsed = clock() - started_at
+    if cancelled:
+        logger.info(
+            "[handle] cancelled session_id=%s elapsed=%.1fs", session_id, elapsed
+        )
+        progress_renderer.resume_session = session_id
+        final_md = progress_renderer.render_progress(elapsed, label="`cancelled`")
+        await _send_or_edit_markdown(
+            cfg.bot,
+            chat_id=chat_id,
+            text=final_md,
+            edit_message_id=progress_id,
+            reply_to_message_id=user_msg_id,
+            disable_notification=True,
+            limit=TELEGRAM_MARKDOWN_LIMIT,
+        )
+        return
+
     status = "done" if saw_agent_message else "error"
     progress_renderer.resume_session = session_id
     final_md = progress_renderer.render_final(elapsed, answer, status=status)
@@ -624,11 +674,51 @@ async def poll_updates(cfg: BridgeConfig):
             yield msg
 
 
+async def _handle_cancel(
+    cfg: BridgeConfig,
+    msg: dict[str, Any],
+    running_tasks: dict[str, asyncio.Task[Any]],
+) -> None:
+    chat_id = msg["chat"]["id"]
+    user_msg_id = msg["message_id"]
+    reply = msg.get("reply_to_message")
+
+    if not reply:
+        await cfg.bot.send_message(
+            chat_id=chat_id,
+            text="reply to the progress message to cancel.",
+            reply_to_message_id=user_msg_id,
+        )
+        return
+
+    session_id = extract_session_id(reply.get("text"))
+    if not session_id:
+        await cfg.bot.send_message(
+            chat_id=chat_id,
+            text="nothing is currently running for that message.",
+            reply_to_message_id=user_msg_id,
+        )
+        return
+
+    task = running_tasks.get(session_id)
+    if not task or task.done():
+        await cfg.bot.send_message(
+            chat_id=chat_id,
+            text="nothing is currently running for that message.",
+            reply_to_message_id=user_msg_id,
+        )
+        return
+
+    logger.info("[cancel] cancelling session_id=%s", session_id)
+    task.cancel()
+
+
 async def _run_main_loop(cfg: BridgeConfig) -> None:
     worker_count = max(1, min(cfg.max_concurrency, 16))
     queue: asyncio.Queue[tuple[int, int, str, str | None]] = asyncio.Queue(
         maxsize=worker_count * 2
     )
+    running_tasks: dict[str, asyncio.Task[Any]] = {}
 
     async def worker() -> None:
         while True:
@@ -640,6 +730,7 @@ async def _run_main_loop(cfg: BridgeConfig) -> None:
                     user_msg_id=user_msg_id,
                     text=text,
                     resume_session=resume_session,
+                    running_tasks=running_tasks,
                 )
             except Exception:
                 logger.exception("[handle] worker failed")
@@ -653,6 +744,11 @@ async def _run_main_loop(cfg: BridgeConfig) -> None:
             async for msg in poll_updates(cfg):
                 text = msg["text"]
                 user_msg_id = msg["message_id"]
+
+                if text == "/cancel":
+                    tg.create_task(_handle_cancel(cfg, msg, running_tasks))
+                    continue
+
                 r = msg.get("reply_to_message") or {}
                 resume_session = resolve_resume_session(text, r.get("text"))
 
diff --git a/src/takopi/exec_render.py b/src/takopi/exec_render.py
index 6164915..b14b563 100644
--- a/src/takopi/exec_render.py
+++ b/src/takopi/exec_render.py
@@ -240,8 +240,8 @@ class ExecProgressRenderer:
         self.recent_actions.append(progress_line)
         return True
 
-    def render_progress(self, elapsed_s: float) -> str:
-        header = format_header(elapsed_s, self.last_item, label="working")
+    def render_progress(self, elapsed_s: float, label: str = "working") -> str:
+        header = format_header(elapsed_s, self.last_item, label=label)
         message = self._assemble(header, list(self.recent_actions))
         return self._append_resume(message)
 
diff --git a/tests/test_exec_bridge.py b/tests/test_exec_bridge.py
index fccb304..6d2a397 100644
--- a/tests/test_exec_bridge.py
+++ b/tests/test_exec_bridge.py
@@ -403,3 +403,167 @@ def test_bridge_flow_sends_progress_edits_and_final_resume() -> None:
     assert session_id in bot.send_calls[-1]["text"]
     assert "resume:" in bot.send_calls[-1]["text"].lower()
     assert len(bot.delete_calls) == 1
+
+
+def test_handle_cancel_without_reply_prompts_user() -> None:
+    from takopi.exec_bridge import BridgeConfig, _handle_cancel
+
+    bot = _FakeBot()
+    runner = _FakeRunner(answer="ok")
+    cfg = BridgeConfig(
+        bot=bot,  # type: ignore[arg-type]
+        runner=runner,  # type: ignore[arg-type]
+        chat_id=123,
+        final_notify=True,
+        startup_msg="",
+        max_concurrency=1,
+    )
+    msg = {"chat": {"id": 123}, "message_id": 10}
+    running_tasks: dict = {}
+
+    asyncio.run(_handle_cancel(cfg, msg, running_tasks))
+
+    assert len(bot.send_calls) == 1
+    assert "reply to the progress message" in bot.send_calls[0]["text"]
+
+
+def test_handle_cancel_with_no_session_id_says_nothing_running() -> None:
+    from takopi.exec_bridge import BridgeConfig, _handle_cancel
+
+    bot = _FakeBot()
+    runner = _FakeRunner(answer="ok")
+    cfg = BridgeConfig(
+        bot=bot,  # type: ignore[arg-type]
+        runner=runner,  # type: ignore[arg-type]
+        chat_id=123,
+        final_notify=True,
+        startup_msg="",
+        max_concurrency=1,
+    )
+    msg = {
+        "chat": {"id": 123},
+        "message_id": 10,
+        "reply_to_message": {"text": "no uuid here"},
+    }
+    running_tasks: dict = {}
+
+    asyncio.run(_handle_cancel(cfg, msg, running_tasks))
+
+    assert len(bot.send_calls) == 1
+    assert "nothing is currently running" in bot.send_calls[0]["text"]
+
+
+def test_handle_cancel_with_finished_task_says_nothing_running() -> None:
+    from takopi.exec_bridge import BridgeConfig, _handle_cancel
+
+    bot = _FakeBot()
+    runner = _FakeRunner(answer="ok")
+    cfg = BridgeConfig(
+        bot=bot,  # type: ignore[arg-type]
+        runner=runner,  # type: ignore[arg-type]
+        chat_id=123,
+        final_notify=True,
+        startup_msg="",
+        max_concurrency=1,
+    )
+    session_id = "019b66fc-64c2-7a71-81cd-081c504cfeb2"
+    msg = {
+        "chat": {"id": 123},
+        "message_id": 10,
+        "reply_to_message": {"text": f"resume: `{session_id}`"},
+    }
+    running_tasks: dict = {}  # Session not in running_tasks
+
+    asyncio.run(_handle_cancel(cfg, msg, running_tasks))
+
+    assert len(bot.send_calls) == 1
+    assert "nothing is currently running" in bot.send_calls[0]["text"]
+
+
+def test_handle_cancel_cancels_running_task() -> None:
+    from takopi.exec_bridge import BridgeConfig, _handle_cancel
+
+    bot = _FakeBot()
+    runner = _FakeRunner(answer="ok")
+    cfg = BridgeConfig(
+        bot=bot,  # type: ignore[arg-type]
+        runner=runner,  # type: ignore[arg-type]
+        chat_id=123,
+        final_notify=True,
+        startup_msg="",
+        max_concurrency=1,
+    )
+    session_id = "019b66fc-64c2-7a71-81cd-081c504cfeb2"
+    msg = {
+        "chat": {"id": 123},
+        "message_id": 10,
+        "reply_to_message": {"text": f"resume: `{session_id}`"},
+    }
+
+    async def run_test():
+        task = asyncio.create_task(asyncio.sleep(10))
+        running_tasks = {session_id: task}
+        await _handle_cancel(cfg, msg, running_tasks)
+        try:
+            await task
+        except asyncio.CancelledError:
+            return True
+        return False
+
+    cancelled = asyncio.run(run_test())
+
+    assert cancelled is True
+    assert len(bot.send_calls) == 0  # No error message sent
+
+
+class _FakeRunnerCancellable:
+    def __init__(self, session_id: str = "019b66fc-64c2-7a71-81cd-081c504cfeb2"):
+        self._session_id = session_id
+
+    async def run_serialized(self, *_args, **kwargs) -> tuple[str, str, bool]:
+        on_event = kwargs.get("on_event")
+        if on_event:
+            await on_event({"type": "thread.started", "thread_id": self._session_id})
+        await asyncio.sleep(10)  # Will be cancelled
+        return (self._session_id, "ok", True)
+
+
+def test_handle_message_cancelled_renders_cancelled_state() -> None:
+    from takopi.exec_bridge import BridgeConfig, _handle_message
+
+    bot = _FakeBot()
+    session_id = "019b66fc-64c2-7a71-81cd-081c504cfeb2"
+    runner = _FakeRunnerCancellable(session_id=session_id)
+    cfg = BridgeConfig(
+        bot=bot,  # type: ignore[arg-type]
+        runner=runner,  # type: ignore[arg-type]
+        chat_id=123,
+        final_notify=True,
+        startup_msg="",
+        max_concurrency=1,
+    )
+    running_tasks: dict = {}
+
+    async def run_test():
+        task = asyncio.create_task(
+            _handle_message(
+                cfg,
+                chat_id=123,
+                user_msg_id=10,
+                text="do something",
+                resume_session=None,
+                running_tasks=running_tasks,
+            )
+        )
+        await asyncio.sleep(0.01)  # Let task start and register
+        assert session_id in running_tasks
+        running_tasks[session_id].cancel()
+        await task
+
+    asyncio.run(run_test())
+
+    assert len(bot.send_calls) == 1  # Progress message
+    assert len(bot.edit_calls) >= 1
+    last_edit = bot.edit_calls[-1]["text"]
+    assert "cancelled" in last_edit.lower()
+    assert session_id in last_edit