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

plugins/cow_cli/cow_cli.py

@@ -26,16 +26,19 @@ from common.log import logger
 from cli import __version__
 
 
-# Known top-level subcommands that cow supports
+# Known top-level subcommands that cow supports.
+# "start" / "stop" / "restart" refer to daemon lifecycle on the host shell;
+# in chat, "/cancel" aborts the in-flight agent run instead.
 KNOWN_COMMANDS = {
     "help", "version", "status", "logs",
     "start", "stop", "restart",
+    "cancel",
     "skill", "context", "config",
     "knowledge", "memory",
     "install-browser",
 }
 
-# Commands that can only run from the CLI (terminal), not in chat
+# Commands that can only run from the CLI (terminal), not in chat.
 CLI_ONLY_COMMANDS = {"start", "stop", "restart"}
 
 # Commands that can only run from chat (need access to in-process memory)
@@ -225,6 +228,7 @@ class CowCliPlugin(Plugin):
             "  /help          显示此帮助",
             "  /version       查看版本",
             "  /status        查看运行状态",
+            "  /cancel        中止当前正在运行的 Agent 任务",
             "  /logs [N]      查看最近N条日志 (默认20)",
             "  /context       查看当前对话上下文信息",
             "  /context clear 清除当前对话上下文",
@@ -250,6 +254,41 @@ class CowCliPlugin(Plugin):
     def _cmd_version(self, args: str, e_context, **_) -> str:
         return f"CowAgent v{__version__}"
 
+    # ------------------------------------------------------------------
+    # cancel — abort the in-flight agent run for the current session.
+    # Fallback handler; in practice chat_channel/web_channel intercept
+    # /cancel earlier so it bypasses the per-session serial queue.
+    # ------------------------------------------------------------------
+
+    def _cmd_cancel(self, args: str, e_context: EventContext, session_id: str = "", **_) -> str:
+        """Signal the running agent to halt at its next checkpoint."""
+        from agent.protocol import get_cancel_registry
+
+        target_session = self._get_session_id(e_context, fallback=session_id)
+        registry = get_cancel_registry()
+
+        # Prefer per-turn request_id (matches the key agent_bridge registered)
+        cancelled = 0
+        request_id = ""
+        if e_context is not None:
+            try:
+                ctx = e_context["context"]
+                request_id = ctx.kwargs.get("request_id") or ctx.get("request_id", "")
+            except Exception:
+                request_id = ""
+
+        if request_id and registry.cancel_request(request_id):
+            cancelled = 1
+
+        # Fall back to session-wide cancel
+        if cancelled == 0 and target_session:
+            cancelled = registry.cancel_session(target_session)
+
+        if cancelled <= 0:
+            return "当前没有可中止的任务。"
+
+        return "🛑 已中止"
+
     # ------------------------------------------------------------------
     # status
     # ------------------------------------------------------------------