diff --git a/template/agent/src/core/logging.py.jinja b/template/agent/src/core/logging.py.jinja
index d8f2d66..951aebf 100644
--- a/template/agent/src/core/logging.py.jinja
+++ b/template/agent/src/core/logging.py.jinja
@@ -1,12 +1,26 @@
 import sys
+from pathlib import Path
 
 from loguru import logger
 
 
-def configure_logging(level: str = "INFO") -> None:
-    """配置 loguru：结构化日志、单一 stderr sink。
+def configure_logging(
+    level: str = "INFO", work_dir: str = "~/{{ project_slug }}"
+) -> None:
+    """配置 loguru：stderr（人类可读）+ {WORK_DIR}/logs/agent.log（JSON 行）。
 
-    生产可改 serialize=True 输出 JSON、或加文件 sink（见 .claude/rules/observability.md）。
+    日志目录在运行时按需创建（不提交 git）。详见 .claude/rules/observability.md。
     """
     logger.remove()
     logger.add(sys.stderr, level=level.upper(), backtrace=False, diagnose=False)
+
+    log_dir = Path(work_dir).expanduser() / "logs"
+    log_dir.mkdir(parents=True, exist_ok=True)
+    logger.add(
+        log_dir / "agent.log",
+        level=level.upper(),
+        serialize=True,
+        rotation="100 MB",
+        retention="14 days",
+        compression="zip",
+    )
diff --git a/template/agent/src/dag/__init__.py b/template/agent/src/dag/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/domain/__init__.py b/template/agent/src/domain/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/domain/exceptions.py b/template/agent/src/domain/exceptions.py
new file mode 100644
index 0000000..fe92915
--- /dev/null
+++ b/template/agent/src/domain/exceptions.py
@@ -0,0 +1,32 @@
+class AgentException(Exception):  # noqa: N818  # 规则约定名为 AgentException
+    """Agent 领域异常基类。
+
+    `code` 对应错误码契约（见 .claude/rules/error-codes.md）。属领域层词汇，
+    由 domain 拥有；框架级 handler 注册在接口层。
+    """
+
+    def __init__(self, code: str, message: str, status_code: int = 500) -> None:
+        self.code = code
+        self.message = message
+        self.status_code = status_code
+        super().__init__(message)
+
+
+class LLMStartupError(AgentException):
+    def __init__(self) -> None:
+        super().__init__("LLM_STARTUP_ERROR", "LLM 启动/连接失败")
+
+
+class ExternalServiceTimeoutError(AgentException):
+    def __init__(self, phase: str) -> None:
+        super().__init__("EXTERNAL_SERVICE_TIMEOUT", f"外部依赖在 {phase} 阶段超时")
+
+
+class ExternalServiceError(AgentException):
+    def __init__(self, detail: str) -> None:
+        super().__init__("EXTERNAL_SERVICE_ERROR", f"外部依赖返回错误: {detail}")
+
+
+class OutputValidationError(AgentException):
+    def __init__(self) -> None:
+        super().__init__("INVALID_INPUT", "无法从输出中提取有效结果")
diff --git a/template/agent/src/export/__init__.py b/template/agent/src/export/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/llm/__init__.py b/template/agent/src/llm/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/main.py.jinja b/template/agent/src/main.py.jinja
index 9f7a593..a8cf997 100644
--- a/template/agent/src/main.py.jinja
+++ b/template/agent/src/main.py.jinja
@@ -1,11 +1,11 @@
-from fastapi import FastAPI
+from fastapi import FastAPI, WebSocket, WebSocketDisconnect
 from loguru import logger
 
 from .core.config import get_settings
 from .core.logging import configure_logging
 
 settings = get_settings()
-configure_logging(settings.log_level)
+configure_logging(settings.log_level, settings.work_dir)
 
 app = FastAPI(
     title="{{ project_name }} Agent",
@@ -17,16 +17,41 @@ app = FastAPI(
 
 @app.get("/health")
 async def health() -> dict[str, str]:
+    """存活探针。"""
     return {"status": "ok"}
 
 
 @app.get("/ready")
 async def ready() -> dict[str, str]:
+    """就绪探针：可在此扩展外部依赖检查。"""
     return {"status": "ok"}
 
 
+@app.websocket("/ws/{session_id}")
+async def ws_endpoint(ws: WebSocket, session_id: str) -> None:
+    """会话接入点（骨架）。
+
+    功能开发时在此驱动 DAG runner：建会话 → 节点编排 → 流式推事件
+    （见 .claude/rules/agent-dag.md）。
+    """
+    await ws.accept()
+    logger.info("ws connected | session_id={}", session_id)
+    try:
+        while True:
+            msg = await ws.receive_json()
+            # TODO: 交给 dag.runner 处理，流式回推事件
+            await ws.send_json({"type": "ack", "received": msg.get("type")})
+    except WebSocketDisconnect:
+        logger.info("ws disconnected | session_id={}", session_id)
+
+
 if __name__ == "__main__":
     import uvicorn
 
     logger.info("Starting agent | port={}", settings.port)
-    uvicorn.run("src.main:app", host="0.0.0.0", port=settings.port, reload=True)
+    uvicorn.run(
+        "src.main:app",
+        host="0.0.0.0",  # noqa: S104  容器内绑定 0.0.0.0 属预期
+        port=settings.port,
+        reload=True,
+    )
diff --git a/template/agent/src/middleware/__init__.py b/template/agent/src/middleware/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/providers/__init__.py b/template/agent/src/providers/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/storage/__init__.py b/template/agent/src/storage/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/utils/__init__.py b/template/agent/src/utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/template/agent/src/utils/ansi.py b/template/agent/src/utils/ansi.py
new file mode 100644
index 0000000..275f6b7
--- /dev/null
+++ b/template/agent/src/utils/ansi.py
@@ -0,0 +1,8 @@
+import re
+
+_ANSI_ESCAPE = re.compile(r"\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])")
+
+
+def strip_ansi(text: str) -> str:
+    """过滤 ANSI 转义码。PTY 驱动的 CLI 输出推送前必须清洗（见 agent-llm-pty.md）。"""
+    return _ANSI_ESCAPE.sub("", text)
diff --git a/template/agent/src/utils/concurrency.py b/template/agent/src/utils/concurrency.py
new file mode 100644
index 0000000..5509dbf
--- /dev/null
+++ b/template/agent/src/utils/concurrency.py
@@ -0,0 +1,10 @@
+import asyncio
+
+
+def make_session_semaphore(max_concurrent: int) -> asyncio.Semaphore:
+    """全局会话并发上限信号量。
+
+    每个会话持有 LLM 子进程/连接等昂贵资源，必须封顶（见 agent-concurrency.md）。
+    超出上限的会话应排队，并向前端反馈位置。
+    """
+    return asyncio.Semaphore(max_concurrent)
diff --git a/template/agent/src/utils/files.py b/template/agent/src/utils/files.py
new file mode 100644
index 0000000..6e02884
--- /dev/null
+++ b/template/agent/src/utils/files.py
@@ -0,0 +1,26 @@
+from pathlib import Path
+
+
+def expand(path: str) -> Path:
+    """展开 ~ 与环境变量，返回绝对 Path。"""
+    return Path(path).expanduser().resolve()
+
+
+def ensure_dir(path: Path) -> Path:
+    """确保目录存在（含父级），返回该目录。"""
+    path.mkdir(parents=True, exist_ok=True)
+    return path
+
+
+def session_dir(work_dir: str, session_id: str) -> Path:
+    """某会话的独立工作目录 {work_dir}/{session_id}/，不存在则创建。"""
+    return ensure_dir(expand(work_dir) / session_id)
+
+
+def safe_within(work_dir: str, candidate: str) -> Path:
+    """校验 candidate 解析后仍在 work_dir 内（防路径穿越），否则抛 ValueError。"""
+    root = expand(work_dir)
+    target = (root / candidate).resolve()
+    if not target.is_relative_to(root):
+        raise ValueError(f"路径越界: {candidate}")
+    return target
diff --git a/template/agent/src/utils/ids.py b/template/agent/src/utils/ids.py
new file mode 100644
index 0000000..16e59ea
--- /dev/null
+++ b/template/agent/src/utils/ids.py
@@ -0,0 +1,6 @@
+import uuid
+
+
+def new_uuid() -> str:
+    """生成新的 UUID4 字符串（用于 session_id 等）。"""
+    return str(uuid.uuid4())