diff --git a/src/daemon/spawner.py b/src/daemon/spawner.py
index 734a486..72d6d14 100644
--- a/src/daemon/spawner.py
+++ b/src/daemon/spawner.py
@@ -235,29 +235,34 @@ curl -X POST http://{self.api_host}:{self.api_port}/api/projects/{project_id}/ta
         new_session: bool = False,
         task_id: Optional[str] = None,
         on_complete: Optional[Any] = None,
+        use_main_session: bool = False,
     ) -> str:
         """Spawn Full Agent（异步非阻塞）
 
         Args:
             on_complete: async callback(agent_id, outcome) — Agent 完成后调用
+            use_main_session: True = 投递到主 Agent session（不传 --session-id）
 
         Returns:
             session_id
         """
-        session_id = str(uuid.uuid4())
+        session_id = None if use_main_session else str(uuid.uuid4())
 
         if self.dry_run:
-            logger.info("[DRY RUN] Would spawn agent %s (session=%s)", agent_id, session_id)
-            self._register_session(session_id, agent_id, task_id, pid=None)
-            return session_id
+            logger.info("[DRY RUN] Would spawn agent %s (session=%s)", agent_id, session_id or "main")
+            self._register_session(session_id or "main", agent_id, task_id, pid=None)
+            return session_id or "main"
 
         cmd = [
             "openclaw", "agent",
             "--agent", agent_id,
-            "--session-id", session_id,
+        ]
+        if session_id:
+            cmd.extend(["--session-id", session_id])
+        cmd.extend([
             "--message", message,
             "--json",
-        ]
+        ])
 
         try:
             proc = await asyncio.create_subprocess_exec(