feat(agent): support user-initiated cancel for in-flight agent runs

channel/chat_channel.py

@@ -438,8 +438,21 @@ class ChatChannel(Channel):
 
         return func
 
+    # Chat commands that must bypass the per-session serial queue,
+    # otherwise /cancel would queue behind the task it tries to cancel.
+    # Use /cancel (not /stop) to avoid colliding with `cow stop` CLI.
+    _BYPASS_QUEUE_COMMANDS = ("/cancel",)
+
     def produce(self, context: Context):
         session_id = context["session_id"]
+
+        # Fast path: /cancel must not enter the queue.
+        if context.type == ContextType.TEXT and context.content:
+            stripped = context.content.strip().lower()
+            if stripped in self._BYPASS_QUEUE_COMMANDS:
+                self._handle_cancel_command(context, session_id)
+                return
+
         with self.lock:
             if session_id not in self.sessions:
                 self.sessions[session_id] = [
@@ -451,6 +464,29 @@ class ChatChannel(Channel):
             else:
                 self.sessions[session_id][0].put(context)
 
+    def _handle_cancel_command(self, context: Context, session_id: str) -> None:
+        """Cancel any in-flight agent run for *session_id* and reply inline.
+
+        Runs synchronously on the caller's thread. Reply is sent through
+        _send_reply so plugins (e.g. logging) still observe it.
+        """
+        try:
+            from agent.protocol import get_cancel_registry
+            from bridge.reply import Reply, ReplyType
+
+            cancelled = get_cancel_registry().cancel_session(session_id)
+            text = (
+                "🛑 已中止"
+                if cancelled > 0
+                else "当前没有可中止的任务。"
+            )
+            logger.info(
+                f"[chat_channel] /cancel fast-path: session={session_id}, cancelled={cancelled}"
+            )
+            self._send_reply(context, Reply(ReplyType.TEXT, text))
+        except Exception as e:
+            logger.warning(f"[chat_channel] /cancel fast-path failed: {e}")
+
     # 消费者函数，单独线程，用于从消息队列中取出消息并处理
     def consume(self):
         while True:

channel/feishu/feishu_channel.py

@@ -752,6 +752,9 @@ class FeiShuChanel(ChatChannel):
         init_in_flight = [False]
         # 一旦初始化失败就长期标记为 disabled，本次回复不再尝试任何流式调用
         disabled = [False]
+        # True after agent_cancelled: agent_end stops rewriting the card
+        # with stale final_response and just finalizes current content.
+        cancelled = [False]
         lock = threading.Lock()
 
         # ---- 异步推送队列 ----------------------------------------------------
@@ -1076,18 +1079,42 @@ class FeiShuChanel(ChatChannel):
                     message_id[0] = None
                     sequence[0] = 0
 
+            elif event_type == "agent_cancelled":
+                # Lock channel into "no-rewrite" mode: the subsequent
+                # agent_end's final_response is from the last *completed*
+                # turn (the user already saw it), so rewriting the card
+                # would duplicate it visually.
+                with lock:
+                    cancelled[0] = True
+
             elif event_type == "agent_end":
                 # 最终回复：用 final_response 覆盖当前流式卡片，然后关闭流式模式。
                 final_response = data.get("final_response", "")
-                if not final_response:
-                    return
-                final_text = str(final_response)
                 # 标记 streamed 让 chat_channel 跳过 send()
                 context["feishu_streamed"] = True
 
                 with lock:
+                    was_cancelled = cancelled[0]
                     has_card = card_id[0] is not None
                     init_busy = init_in_flight[0]
+                    pending_text = current_text[0]
+
+                if was_cancelled:
+                    # Cancelled path: finalize the in-flight card with
+                    # partial output (or a short marker if empty); drop
+                    # stale final_response to avoid duplicating last turn.
+                    if has_card:
+                        _drain_push_queue()
+                        partial = (pending_text or "").rstrip()
+                        final_text = partial or "_(已中止)_"
+                        _stream_update_text(final_text)
+                        _close_streaming_mode(final_text)
+                    push_queue.put(None)
+                    return
+
+                if not final_response:
+                    return
+                final_text = str(final_response)
 
                 # 罕见情况：agent_end 触发时还没创建过卡片（极快返回 / 没有
                 # message_update），主动创建一张承载 final_text。

channel/web/chat.html

@@ -445,7 +445,7 @@
                                                bg-primary-400 text-white hover:bg-primary-500
                                                disabled:bg-slate-300 dark:disabled:bg-slate-600
                                                disabled:cursor-not-allowed cursor-pointer transition-colors duration-150"
-                                        disabled onclick="sendMessage()">
+                                        disabled>
                                     <i class="fas fa-paper-plane text-sm"></i>
                                 </button>
                             </div>

channel/web/static/css/console.css

@@ -1367,3 +1367,35 @@
     text-align: right;
 }
 .voice-pill audio { display: none; }
+
+/* Send button toggles into a Stop button while an SSE stream is in flight.
+   Match the look of the disabled send button (light grey block + white
+   glyph) so it reads as the same visual element, just paused/idle from
+   sending perspective and clickable to stop. */
+#send-btn.send-btn-cancel {
+    background-color: rgb(203 213 225) !important; /* slate-300, == disabled send-btn */
+    color: white !important;
+}
+#send-btn.send-btn-cancel:hover {
+    background-color: rgb(148 163 184) !important; /* slate-400 */
+}
+#send-btn.send-btn-cancel:disabled {
+    background-color: rgb(226 232 240) !important; /* slate-200, while stop is in flight */
+    color: white !important;
+    cursor: progress;
+}
+.dark #send-btn.send-btn-cancel {
+    background-color: rgb(71 85 105) !important; /* slate-600, == dark disabled send-btn */
+    color: white !important;
+}
+.dark #send-btn.send-btn-cancel:hover {
+    background-color: rgb(100 116 139) !important; /* slate-500 */
+}
+.dark #send-btn.send-btn-cancel:disabled {
+    background-color: rgb(51 65 85) !important; /* slate-700 */
+    color: rgb(203 213 225) !important;
+}
+
+.agent-cancelled-tag {
+    font-style: italic;
+}

channel/web/static/js/console.js

@@ -1016,7 +1016,60 @@ const inputHistory = [];
 let historyIdx = -1;
 let historySavedDraft = '';
 
+// While an SSE stream is in flight, the send button morphs into a cancel
+// button. Only one in-flight request is supported at a time.
+let activeRequestId = null;
+let sendBtnMode = 'send'; // 'send' | 'cancel'
+
+function setSendBtnCancelMode(requestId) {
+    activeRequestId = requestId;
+    sendBtnMode = 'cancel';
+    sendBtn.disabled = false;
+    sendBtn.classList.add('send-btn-cancel');
+    sendBtn.title = (currentLang === 'zh' ? '中止' : 'Cancel');
+    sendBtn.innerHTML = '<i class="fas fa-stop text-sm"></i>';
+}
+
+function resetSendBtnSendMode() {
+    activeRequestId = null;
+    sendBtnMode = 'send';
+    sendBtn.classList.remove('send-btn-cancel');
+    sendBtn.title = '';
+    sendBtn.innerHTML = '<i class="fas fa-paper-plane text-sm"></i>';
+    updateSendBtnState();
+}
+
+function requestCancel() {
+    const reqId = activeRequestId;
+    if (!reqId) return;
+    fetch('/cancel', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ request_id: reqId, session_id: sessionId, lang: currentLang }),
+    }).catch(err => {
+        console.warn('[cancel] request failed', err);
+    });
+    // Optimistic UI lock so the click visibly registers before the SSE
+    // "cancelled" event arrives.
+    sendBtn.disabled = true;
+    sendBtn.title = (currentLang === 'zh' ? '已中止' : 'Cancelled');
+}
+
+// Button click is the only path to Cancel. Pressing Enter still calls
+// sendMessage() so users can submit "/cancel" as a regular slash command.
+sendBtn.addEventListener('click', () => {
+    if (sendBtnMode === 'cancel') {
+        requestCancel();
+    } else {
+        sendMessage();
+    }
+});
+
 function updateSendBtnState() {
+    if (sendBtnMode === 'cancel') {
+        // Don't downgrade a Cancel button on input edits.
+        return;
+    }
     sendBtn.disabled = uploadingCount > 0 || (!chatInput.value.trim() && pendingAttachments.length === 0);
 }
 
@@ -1264,6 +1317,7 @@ const SLASH_COMMANDS = [
     { cmd: '/knowledge on',        desc: '开启知识库' },
     { cmd: '/knowledge off',       desc: '关闭知识库' },
     { cmd: '/config',              desc: '查看当前配置' },
+    { cmd: '/cancel',              desc: '中止当前正在运行的 Agent 任务' },
     { cmd: '/logs',                desc: '查看最近日志' },
     { cmd: '/version',             desc: '查看版本' },
 ];
@@ -1534,6 +1588,7 @@ function sendVoiceMessage(text, audioUrl) {
         stream: true,
         timestamp: timestamp.toISOString(),
         is_voice: true,
+        lang: currentLang,
     };
 
     const MAX_RETRIES = 2;
@@ -1547,7 +1602,12 @@ function sendVoiceMessage(text, audioUrl) {
         .then(r => r.json())
         .then(data => {
             if (data.status === 'success') {
-                if (data.stream) {
+                if (data.inline_reply) {
+                    // Synchronous fast-path reply (e.g. /cancel); skip SSE.
+                    loadingEl.remove();
+                    addBotMessage(data.inline_reply, new Date());
+                } else if (data.stream) {
+                    setSendBtnCancelMode(data.request_id);
                     startSSE(data.request_id, loadingEl, timestamp, titleInfo);
                 } else {
                     loadingContainers[data.request_id] = loadingEl;
@@ -1555,6 +1615,7 @@ function sendVoiceMessage(text, audioUrl) {
             } else {
                 loadingEl.remove();
                 addBotMessage(t('error_send'), new Date());
+                resetSendBtnSendMode();
             }
         })
         .catch(err => {
@@ -1591,6 +1652,10 @@ function addUserVoiceMessage(audioUrl, caption, timestamp) {
 }
 
 function sendMessage() {
+    // Do NOT branch on sendBtnMode here: Enter should always send (so
+    // typing "/cancel" submits normally). Cancel is wired only to the
+    // send button's pointer click — see send-btn listener above.
+
     const text = chatInput.value.trim();
     if (!text && pendingAttachments.length === 0) return;
 
@@ -1619,7 +1684,7 @@ function sendMessage() {
     renderAttachmentPreview();
     sendBtn.disabled = true;
 
-    const body = { session_id: sessionId, message: text, stream: true, timestamp: timestamp.toISOString() };
+    const body = { session_id: sessionId, message: text, stream: true, timestamp: timestamp.toISOString(), lang: currentLang };
     if (attachments.length > 0) {
         body.attachments = attachments.map(a => ({
             file_path: a.file_path,
@@ -1641,7 +1706,13 @@ function sendMessage() {
         .then(r => r.json())
         .then(data => {
             if (data.status === 'success') {
-                if (data.stream) {
+                if (data.inline_reply) {
+                    // Channel handled synchronously (e.g. /cancel fast-path);
+                    // render as a bot bubble and skip SSE entirely.
+                    loadingEl.remove();
+                    addBotMessage(data.inline_reply, new Date());
+                } else if (data.stream) {
+                    setSendBtnCancelMode(data.request_id);
                     startSSE(data.request_id, loadingEl, timestamp, titleInfo);
                 } else {
                     loadingContainers[data.request_id] = loadingEl;
@@ -1649,12 +1720,14 @@ function sendMessage() {
             } else {
                 loadingEl.remove();
                 addBotMessage(t('error_send'), new Date());
+                resetSendBtnSendMode();
             }
         })
         .catch(err => {
             if (err.name === 'AbortError') {
                 loadingEl.remove();
                 addBotMessage(t('error_timeout'), new Date());
+                resetSendBtnSendMode();
                 return;
             }
             if (attempt < MAX_RETRIES) {
@@ -1664,6 +1737,7 @@ function sendMessage() {
             }
             loadingEl.remove();
             addBotMessage(t('error_send'), new Date());
+            resetSendBtnSendMode();
         });
     }
 
@@ -1919,14 +1993,33 @@ function startSSE(requestId, loadingEl, timestamp, titleInfo) {
                 stepsEl.appendChild(wrap);
                 scrollChatToBottom();
 
+            } else if (item.type === 'cancelled') {
+                // Agent acknowledged the stop; mark the bubble. A trailing
+                // "done" still arrives with the partial answer.
+                ensureBotEl();
+                if (currentReasoningEl) {
+                    finalizeThinking(currentReasoningEl, reasoningStartTime, reasoningText);
+                    currentReasoningEl = null;
+                    reasoningText = '';
+                }
+                if (!botEl.querySelector('.agent-cancelled-tag')) {
+                    const tag = document.createElement('div');
+                    tag.className = 'agent-cancelled-tag text-xs text-amber-600 dark:text-amber-400 mt-1';
+                    tag.textContent = (currentLang === 'zh') ? '已中止' : 'Cancelled';
+                    stepsEl.appendChild(tag);
+                }
+                resetSendBtnSendMode();
+
             } else if (item.type === 'done') {
                 // Don't close the stream yet: the backend keeps it open
                 // for a short tail to deliver async attachments such as
                 // TTS audio (`voice_attach`). It will close the stream on
                 // its own via onerror once the tail expires.
                 done = true;
+                resetSendBtnSendMode();
 
-                const finalText = item.content || accumulatedText;
+                const finalTextRaw = item.content || accumulatedText;
+                const finalText = localizeCancelMarker(finalTextRaw);
 
                 if (!botEl && finalText) {
                     if (loadingEl) { loadingEl.remove(); loadingEl = null; }
@@ -1934,7 +2027,7 @@ function startSSE(requestId, loadingEl, timestamp, titleInfo) {
                 } else if (botEl) {
                     contentEl.classList.remove('sse-streaming');
                     if (finalText) contentEl.innerHTML = renderMarkdown(finalText);
-                    contentEl.dataset.rawMd = finalText || '';
+                    contentEl.dataset.rawMd = finalTextRaw || '';
                     const copyBtn = botEl.querySelector('.copy-msg-btn');
                     if (copyBtn && finalText) copyBtn.style.display = '';
                     applyHighlighting(botEl);
@@ -1964,6 +2057,7 @@ function startSSE(requestId, loadingEl, timestamp, titleInfo) {
                 delete activeStreams[requestId];
                 if (loadingEl) { loadingEl.remove(); loadingEl = null; }
                 addBotMessage(t('error_send'), new Date());
+                resetSendBtnSendMode();
             }
         };
 
@@ -2000,6 +2094,7 @@ function startSSE(requestId, loadingEl, timestamp, titleInfo) {
                 applyHighlighting(botEl);
                 bindChatKnowledgeLinks(botEl);
             }
+            resetSendBtnSendMode();
         };
     }
 
@@ -2238,13 +2333,23 @@ function _renderSentFileFromToolResult(step) {
         `<i class="fas fa-file-download" style="color:#6b7280;"></i> ${escapeHtml(fileName)}</a></div>`;
 }
 
+// Cosmetic translator for cancel markers persisted in history.
+// History keeps the English canonical form for the LLM; only display is localized.
+function localizeCancelMarker(text) {
+    if (!text) return text;
+    if (currentLang !== 'zh') return text;
+    return text
+        .replace(/_\(Cancelled by user\)_/g, '_(用户已中止)_')
+        .replace(/_\(Cancelled\)_/g, '_(已中止)_');
+}
+
 function createBotMessageEl(content, timestamp, requestId, msg) {
     const el = document.createElement('div');
     el.className = 'flex gap-3 px-4 sm:px-6 py-3';
     if (requestId) el.dataset.requestId = requestId;
 
     let stepsHtml = '';
-    let displayContent = content;
+    let displayContent = localizeCancelMarker(content);
 
     if (msg && msg.steps && msg.steps.length > 0) {
         // New format: ordered steps with interleaved content

channel/web/web_channel.py

@@ -93,6 +93,15 @@ def _require_auth():
                             json.dumps({"status": "error", "message": "Unauthorized"}))
 
 
+# Localized text for /cancel system replies. Web is the only channel that
+# honors a per-request `lang`; other channels reply in Chinese by default.
+def _cancel_reply_text(cancelled: int, lang: str) -> str:
+    en = lang.startswith("en")
+    if cancelled > 0:
+        return "🛑 Cancelled." if en else "🛑 已中止"
+    return "Nothing to cancel." if en else "当前没有可中止的任务。"
+
+
 def _get_upload_dir() -> str:
     from common.utils import expand_path
     ws_root = expand_path(conf().get("agent_workspace", "~/cow"))
@@ -437,6 +446,18 @@ class WebChannel(ChatChannel):
                     "timestamp": time.time(),
                 })
 
+            elif event_type == "agent_cancelled":
+                # Push an explicit cancelled SSE event so the frontend
+                # marks the bubble as stopped. A trailing "done" still
+                # arrives with the partial answer.
+                final_response = data.get("final_response", "")
+                q.put({
+                    "type": "cancelled",
+                    "content": final_response,
+                    "request_id": request_id,
+                    "timestamp": time.time(),
+                })
+
             elif event_type == "agent_end":
                 # Safety net: if the agent finishes with an empty final_response,
                 # chat_channel skips _send_reply (because reply.content is empty),
@@ -756,6 +777,25 @@ class WebChannel(ChatChannel):
             # desire_rtype concept used by other channels).
             is_voice_input = bool(json_data.get('is_voice', False))
 
+            # Fast path for /cancel: bypass the session queue and SSE setup.
+            # Web frontend (stream=true) only listens to SSE, so we return an
+            # inline_reply payload to be rendered synchronously.
+            stripped_prompt = (prompt or "").strip().lower()
+            if stripped_prompt == "/cancel":
+                from agent.protocol import get_cancel_registry
+                cancelled = get_cancel_registry().cancel_session(session_id)
+                lang = (json_data.get('lang') or 'zh').lower()
+                msg_text = _cancel_reply_text(cancelled, lang)
+                logger.info(
+                    f"[WebChannel] /cancel fast-path: session={session_id}, cancelled={cancelled}, lang={lang}"
+                )
+                return json.dumps({
+                    "status": "success",
+                    "request_id": "",
+                    "stream": False,
+                    "inline_reply": msg_text,
+                })
+
             # Append file references to the prompt (same format as QQ channel)
             if attachments:
                 file_refs = []
@@ -862,6 +902,11 @@ class WebChannel(ChatChannel):
                 if itype == "done":
                     post_done = True
                     post_deadline = time.time() + POST_DONE_TAIL_SECONDS
+                elif itype == "cancelled":
+                    # Close SSE tail quickly after cancel; don't wait for the
+                    # full TTS tail since the user already pressed Stop.
+                    post_done = True
+                    post_deadline = time.time() + 3
                 elif itype == "voice_attach":
                     # WSGI buffers the previous chunk until the next yield;
                     # shrink the tail so the generator wakes up quickly to
@@ -872,6 +917,59 @@ class WebChannel(ChatChannel):
         finally:
             self.sse_queues.pop(request_id, None)
 
+    def cancel_request(self):
+        """
+        Cancel an in-flight agent run.
+
+        Body: {"request_id": "...", "session_id": "..."}
+        Either field is sufficient; request_id is preferred when known.
+        Always returns success even when nothing was running, so the
+        client's UX is idempotent.
+        """
+        try:
+            from agent.protocol import get_cancel_registry
+
+            data = web.data()
+            try:
+                json_data = json.loads(data) if data else {}
+            except Exception:
+                json_data = {}
+
+            request_id = (json_data.get("request_id") or "").strip()
+            session_id = (json_data.get("session_id") or "").strip()
+            lang = (json_data.get("lang") or "zh").lower()
+
+            registry = get_cancel_registry()
+            cancelled = 0
+
+            if request_id:
+                if registry.cancel_request(request_id):
+                    cancelled = 1
+
+            if cancelled == 0 and session_id:
+                cancelled = registry.cancel_session(session_id)
+
+            if request_id and request_id in self.sse_queues:
+                self.sse_queues[request_id].put({
+                    "type": "cancelled",
+                    "content": "Cancelled" if lang.startswith("en") else "已中止",
+                    "request_id": request_id,
+                    "timestamp": time.time(),
+                })
+
+            logger.info(
+                f"[WebChannel] cancel request: request_id={request_id!r}, "
+                f"session_id={session_id!r}, cancelled={cancelled}"
+            )
+            return json.dumps({
+                "status": "success",
+                "cancelled": cancelled,
+            })
+
+        except Exception as e:
+            logger.error(f"[WebChannel] cancel_request error: {e}")
+            return json.dumps({"status": "error", "message": str(e)})
+
     def poll_response(self):
         """
         Poll for responses using the session_id.
@@ -967,6 +1065,7 @@ class WebChannel(ChatChannel):
             '/api/voice/tts', 'VoiceTtsHandler',
             '/poll', 'PollHandler',
             '/stream', 'StreamHandler',
+            '/cancel', 'CancelHandler',
             '/chat', 'ChatHandler',
             '/config', 'ConfigHandler',
             '/api/models', 'ModelsHandler',
@@ -1240,6 +1339,12 @@ class PollHandler:
         return WebChannel().poll_response()
 
 
+class CancelHandler:
+    def POST(self):
+        _require_auth()
+        return WebChannel().cancel_request()
+
+
 class StreamHandler:
     def GET(self):
         _require_auth()

channel/wecom_bot/wecom_bot_channel.py

@@ -440,6 +440,17 @@ class WecomBotChannel(ChatChannel):
                     state["current"] = ""
                 _push_stream(state, force=True)
 
+            elif event_type == "agent_cancelled":
+                # Flush partial output and strip trailing "---" separator
+                # left over from previous turn, to avoid a dangling divider.
+                if state["current"]:
+                    state["committed"] += state["current"]
+                    state["current"] = ""
+                state["committed"] = state["committed"].rstrip()
+                if state["committed"].endswith("---"):
+                    state["committed"] = state["committed"][:-3].rstrip()
+                _push_stream(state, force=True)
+
         return on_event
 
     # ------------------------------------------------------------------