diff --git a/core/main_terminal_parts/tools_definition/agent_tools.py b/core/main_terminal_parts/tools_definition/agent_tools.py
index b9af9447..87245928 100644
--- a/core/main_terminal_parts/tools_definition/agent_tools.py
+++ b/core/main_terminal_parts/tools_definition/agent_tools.py
@@ -133,7 +133,7 @@ class ToolsDefinitionAgentToolsMixin:
                                     },
                                     "deliverables_dir": {
                                         "type": "string",
-                                        "description": "交付文件夹的相对路径（相对于项目根目录）。子智能体会将所有结果文件放在此目录。\n\n要求：必须是不存在的新目录；若目录不存在会自动创建；若目录已存在（无论是否为空）将报错。\n\n留空则使用默认路径：sub_agent_results/agent_{agent_id}\n\n示例：'docs/api'、'reports/performance'、'tests/generated'"
+                                        "description": "交付文件夹的相对路径（相对于项目根目录）。子智能体会将所有结果文件放在此目录。\n\n显式传入时：必须是不存在的新目录，若已存在（无论是否为空）将报错。\n\n留空时：自动在 .astrion/sub_agent_results/ 下创建（如 agent_{agent_id}），最终路径会作为工具结果返回。\n\n示例：'docs/api'、'reports/performance'、'tests/generated'"
                                     },
                                     "run_in_background": {
                                         "type": "boolean",
@@ -149,7 +149,7 @@ class ToolsDefinitionAgentToolsMixin:
                                         "description": "子智能体思考模式，根据任务复杂度选择：\n\nfast（快速模式）- 适合简单明确的任务：\n- 网络信息搜集和整理\n- 批量文件读取和简单处理\n- 执行已知的命令序列\n- 生成简单的文档或报告\n- 数据格式转换\n\nthinking（思考模式）- 适合复杂任务：\n- 代码架构分析和重构设计\n- 复杂算法实现和优化\n- 多步骤问题诊断和调试\n- 技术方案选型和对比\n- 需要深度推理的代码审查\n\n不填则使用默认模式。"
                                     }
                                 }),
-                                "required": ["agent_id", "summary", "task", "deliverables_dir", "thinking_mode"]
+                                "required": ["agent_id", "summary", "task", "thinking_mode"]
                             }
                         }
                     },
diff --git a/modules/sub_agent/creation.py b/modules/sub_agent/creation.py
index 26acca54..6c84912b 100644
--- a/modules/sub_agent/creation.py
+++ b/modules/sub_agent/creation.py
@@ -103,22 +103,22 @@ class SubAgentCreationMixin:
             return "任务摘要不能为空"
         if not task or not task.strip():
             return "任务详情不能为空"
-        # 多智能体模式不需要交付目录
-        if not multi_agent_mode and target_dir is None:
-            return "指定文件夹不能为空"
+        # 交付目录不再必填：传统模式未指定时自动创建（见 _resolve_deliverables_dir）
         return None
 
     def _generate_task_id(self, agent_id: int) -> str:
         suffix = uuid.uuid4().hex[:6]
         return f"sub_{agent_id}_{int(time.time())}_{suffix}"
 
-    def _resolve_deliverables_dir(self, relative_dir: Optional[str], *, multi_agent_mode: bool = False) -> Path:
+    def _resolve_deliverables_dir(self, relative_dir: Optional[str], *, agent_id: int = 0, multi_agent_mode: bool = False) -> Path:
         relative_dir = (relative_dir or "").strip()
         # 多智能体模式：没有交付目录概念，直接使用项目根目录
         if multi_agent_mode and not relative_dir:
             return self.project_path.resolve()
         if not relative_dir:
-            raise ValueError(tr("sub_agent_creation.deliverables_dir_required"))
+            # 未显式指定交付目录：在运行时目录 .astrion/sub_agent_results/ 下自动创建
+            #（撞名自动加后缀，保证总能建成），实际路径由 create_sub_agent 结果返回
+            return self._auto_deliverables_dir(agent_id)
         deliverables_path = (self.project_path / relative_dir).resolve()
         if not str(deliverables_path).startswith(str(self.project_path)):
             raise ValueError(tr("sub_agent_creation.deliverables_dir_outside"))
@@ -126,3 +126,15 @@ class SubAgentCreationMixin:
             raise ValueError(tr("sub_agent_creation.deliverables_dir_not_new"))
         deliverables_path.mkdir(parents=True, exist_ok=True)
         return deliverables_path
+
+    def _auto_deliverables_dir(self, agent_id: int) -> Path:
+        """未指定交付目录时自动创建：.astrion/sub_agent_results/agent_{id}（撞名追加后缀）。"""
+        base = (self.project_path / ".astrion" / "sub_agent_results").resolve()
+        base.mkdir(parents=True, exist_ok=True)
+        candidate = base / f"agent_{agent_id}"
+        suffix = 2
+        while candidate.exists():
+            candidate = base / f"agent_{agent_id}_{suffix}"
+            suffix += 1
+        candidate.mkdir(parents=True, exist_ok=True)
+        return candidate
diff --git a/modules/sub_agent/manager.py b/modules/sub_agent/manager.py
index fa62f166..6a599ac4 100644
--- a/modules/sub_agent/manager.py
+++ b/modules/sub_agent/manager.py
@@ -284,7 +284,7 @@ class SubAgentManager(SubAgentStateMixin, SubAgentStatsMixin, SubAgentCreationMi
         task_root.mkdir(parents=True, exist_ok=True)
 
         try:
-            deliverables_path = self._resolve_deliverables_dir(deliverables_dir, multi_agent_mode=multi_agent_mode)
+            deliverables_path = self._resolve_deliverables_dir(deliverables_dir, agent_id=agent_id, multi_agent_mode=multi_agent_mode)
         except ValueError as exc:
             # 回滚已创建的任务目录，避免残留状态（交付目录校验失败时 deliverables 不会创建）
             shutil.rmtree(task_root, ignore_errors=True)