F2: delegate prompt tasks to native Reasoner or OpenCode backends

backend/services/brains/prompt_brain.py

@@ -102,7 +102,7 @@ class PromptBrain(BaseBrain):
 
     def system_prompt(self, cfg: AssistantConfig) -> str:
         prompt = self._store.render(cfg.prompt) if self._dynamic_enabled else cfg.prompt
-        if cfg.runtimeMode == "pipeline" and any(tool.type == "task" for tool in cfg.tools):
+        if cfg.runtimeMode == "pipeline" and cfg.task_backend is not None:
             from services.brains.prompt_tasks import TASK_HINT
             prompt += "\n" + TASK_HINT
         return prompt
@@ -158,20 +158,6 @@ class PromptBrain(BaseBrain):
             ):
                 logger.warning(f"跳过客户端未上报的工具: {tool.function_name}")
                 continue
-            if tool.type == "task":
-                if cfg.runtimeMode != "pipeline":
-                    raise ValueError("后台任务工具仅支持提示词 Pipeline")
-                from services.brains.prompt_tasks import PromptTaskBridge
-                if self._task_bridge is not None:
-                    raise ValueError("最多绑定一个后台任务工具")
-                self._task_bridge = PromptTaskBridge(cfg, runtime, self._tools)
-                for schema, handler in self._task_bridge.functions(tool, binding_by_id[tool.id]):
-                    if schema.name in registered_names:
-                        raise ValueError("后台任务函数名与已有工具冲突")
-                    schemas.append(schema)
-                    registered_names.add(schema.name)
-                    runtime.llm.register_function(schema.name, handler, cancel_on_interruption=False)
-                continue
             if tool.type == "system":
                 schema, handler = self._make_system_tool(tool, runtime)
             elif tool.type in {"http", "mcp", "client"}:
@@ -195,6 +181,17 @@ class PromptBrain(BaseBrain):
                 handler,
                 cancel_on_interruption=policy.cancel_on_interruption,
             )
+        if cfg.task_backend is not None:
+            if cfg.runtimeMode != "pipeline":
+                raise ValueError("任务后端仅支持提示词 Pipeline")
+            from services.brains.prompt_tasks import PromptTaskBridge
+            self._task_bridge = PromptTaskBridge(cfg, runtime, self._tools)
+            for schema, handler in self._task_bridge.functions():
+                if schema.name in registered_names:
+                    raise ValueError("任务委派函数名与已有工具冲突")
+                schemas.append(schema)
+                registered_names.add(schema.name)
+                runtime.llm.register_function(schema.name, handler, cancel_on_interruption=False)
         runtime.set_tools(schemas)
 
     async def close(self):