feat: add /stop command to kill running agent process

- /stop, /cancel, /kill aliases all supported
- SIGTERM first (allows graceful AbortController cleanup), SIGKILL after 5s
- Wired through session-commands → GroupQueue.killProcess()

src/group-queue.ts

@@ -503,6 +503,43 @@ export class GroupQueue {
     }
   }
 
+  /**
+   * Immediately kill the running agent process for a group.
+   * Returns true if a process was killed, false if nothing was running.
+   */
+  killProcess(groupJid: string): boolean {
+    const state = this.getGroup(groupJid);
+    const proc = state.process;
+    if (!proc || !this.isProcessAlive(proc)) {
+      return false;
+    }
+    logger.info(
+      {
+        groupJid,
+        runId: state.currentRunId,
+        processName: state.processName,
+      },
+      'Killing agent process via /stop command',
+    );
+    try {
+      // SIGTERM allows the runner to call AbortController.abort() for graceful cleanup.
+      // Falls back to SIGKILL after 5 seconds if the process doesn't exit.
+      proc.kill('SIGTERM');
+      setTimeout(() => {
+        if (this.isProcessAlive(proc)) {
+          try {
+            proc.kill('SIGKILL');
+          } catch {
+            /* already dead */
+          }
+        }
+      }, 5000);
+    } catch {
+      /* already dead */
+    }
+    return true;
+  }
+
   private async runForGroup(
     groupJid: string,
     reason: 'messages' | 'drain',

src/message-runtime.ts

@@ -581,6 +581,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
             });
             return formatRoomReviewReadyMessage(result);
           },
+          killProcess: () => deps.queue.killProcess(chatJid),
         },
       });
       if (cmdResult.handled) return cmdResult.success;
@@ -917,7 +918,6 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
           );
         }
       }
-
     }
   };
 

src/session-commands.test.ts

@@ -176,6 +176,7 @@ function makeDeps(
     isAdminSender: vi.fn().mockReturnValue(false),
     canSenderInteract: vi.fn().mockReturnValue(true),
     markReviewReady: vi.fn().mockResolvedValue('Review snapshot updated.'),
+    killProcess: vi.fn().mockReturnValue(false),
     ...overrides,
   };
 }

src/session-commands.ts

@@ -34,6 +34,7 @@ export function extractSessionCommand(
   if (text === '/compact') return '/compact';
   if (text === '/clear') return '/clear';
   if (text === '/review' || text === '/review-ready') return '/review';
+  if (text === '/stop' || text === '/cancel' || text === '/kill') return '/stop';
   return null;
 }
 
@@ -79,6 +80,8 @@ export interface SessionCommandDeps {
   /** Whether the denied sender would normally be allowed to interact (for denial messages). */
   canSenderInteract: (msg: NewMessage) => boolean;
   markReviewReady: () => Promise<string | null>;
+  /** Kill the currently running agent process for this group. Returns true if a process was killed. */
+  killProcess: () => boolean;
 }
 
 function resultToText(result: string | object | null | undefined): string {
@@ -173,6 +176,17 @@ export async function handleSessionCommand(opts: {
     return { handled: true, success: true };
   }
 
+  if (command === '/stop') {
+    const killed = deps.killProcess();
+    deps.advanceCursor(cmdMsg.timestamp);
+    await deps.sendMessage(
+      killed
+        ? 'Agent stopped.'
+        : 'No agent is currently running in this room.',
+    );
+    return { handled: true, success: true };
+  }
+
   const cmdIndex = missedMessages.indexOf(cmdMsg);
   const preCompactMsgs = missedMessages.slice(0, cmdIndex);