diff --git a/selfdrive/c3_client.py b/selfdrive/c3_client.py
new file mode 100755
index 00000000..27126cd7
--- /dev/null
+++ b/selfdrive/c3_client.py
@@ -0,0 +1,225 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+C3 Client — 部署到 C3 设备上
+与 C3 Director 服务端通信
+支持远程指令执行、tmux 故障诊断、心跳保活
+
+通过 openpilot 的 PythonProcess 自动启动：
+  PythonProcess("c3-client", "selfdrive.c3_client", always_run),
+"""
+
+import asyncio
+import json
+import os
+import subprocess
+import sys
+import traceback
+from datetime import datetime
+
+import websockets
+
+# openpilot 基础模块
+from openpilot.system.hardware import HARDWARE, PC
+from openpilot.common.params import Params
+from openpilot.common.swaglog import cloudlog
+
+# ================= 配置 =================
+SERVER_URL = "ws://1.15.136.221:8500"
+HEARTBEAT_INTERVAL = 15  # 心跳间隔秒数
+RECONNECT_DELAY = 5      # 断线重连等待秒数
+
+# ================= 设备标识 =================
+_params = Params()
+
+
+def get_serial():
+  """通过 HARDWARE API 获取设备序列号"""
+  try:
+    return HARDWARE.get_serial()
+  except Exception:
+    return os.uname().nodename
+
+
+def get_dongle_id():
+  """通过 Params 获取 dongle_id"""
+  try:
+    dongle = _params.get("DongleId")
+    return dongle if dongle else ""
+  except Exception:
+    return ""
+
+
+def get_git_branch():
+  """获取当前 openpilot 的分支名"""
+  try:
+    result = subprocess.run(
+      ["git", "rev-parse", "--abbrev-ref", "HEAD"],
+      capture_output=True, text=True, timeout=5,
+      cwd=os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    )
+    return result.stdout.strip() if result.returncode == 0 else ""
+  except Exception:
+    return ""
+
+
+# ================= 指令执行 =================
+async def execute_cmd(command, timeout=30):
+  """执行 shell 命令，返回 stdout+stderr"""
+  try:
+    result = await asyncio.wait_for(
+      asyncio.create_subprocess_shell(
+        command,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT
+      ),
+      timeout=timeout
+    )
+    stdout, _ = await result.communicate()
+    return {
+      "status": "ok",
+      "output": stdout.decode(errors="replace"),
+      "returncode": result.returncode
+    }
+  except asyncio.TimeoutError:
+    return {"status": "error", "output": "命令执行超时"}
+  except Exception as e:
+    return {"status": "error", "output": str(e)}
+
+
+async def execute_tmux():
+  """执行 tmux a 获取当前 tmux 输出（故障诊断）"""
+  commands = [
+    "tmux capture-pane -t $(tmux list-sessions -F '#{session_name}' 2>/dev/null | head -1) -p -S -200 2>/dev/null",
+    "tmux list-sessions 2>/dev/null && tmux send-keys -t $(tmux list-sessions -F '#{session_name}' 2>/dev/null | head -1) '' Enter && sleep 0.5 && tmux capture-pane -t $(tmux list-sessions -F '#{session_name}' 2>/dev/null | head -1) -p -S -200 2>/dev/null",
+    "tmux has-session 2>/dev/null && tmux send-keys -t $(tmux list-sessions -F '#{session_name}' 2>/dev/null | head -1) '' && sleep 0.5 && tmux capture-pane -t $(tmux list-sessions -F '#{session_name}' 2>/dev/null | head -1) -p -S -200 2>/dev/null || echo 'TMUX_ERROR: no session found'",
+  ]
+
+  tmux_check = await execute_cmd("ps aux | grep tmux | grep -v grep", timeout=3)
+  if not tmux_check.get("output", "").strip():
+    return {"status": "ok", "output": "⚠️ 设备上未检测到 tmux 进程运行"}
+
+  sessions_result = await execute_cmd("tmux list-sessions 2>&1", timeout=3)
+  if "error" in sessions_result.get("output", ""):
+    return {"status": "ok", "output": f"⚠️ 无法获取 tmux 会话\n{sessions_result['output']}"}
+
+  result = await execute_cmd(commands[0], timeout=5)
+  if result["status"] == "ok" and result.get("output", "").strip():
+    session_info = await execute_cmd("tmux list-sessions 2>&1", timeout=3)
+    output = f"--- tmux sessions ---\n{session_info.get('output', '')}\n\n--- capture output ---\n{result['output']}"
+    return {"status": "ok", "output": output}
+  else:
+    return {"status": "ok", "output": f"⚠️ 无法捕获 tmux 输出\n{sessions_result.get('output', '')}"}
+
+
+# ================= 消息处理 =================
+async def handle_message(data, ws):
+  """处理服务端发来的消息"""
+  msg_type = data.get("type")
+  msg_id = data.get("id")
+  content = data.get("content", "")
+  timeout = data.get("timeout", 15)
+
+  if msg_type == "cmd":
+    result = await execute_cmd(content, timeout)
+  elif msg_type == "tmux":
+    result = await execute_tmux()
+  elif msg_type == "ping":
+    result = {"status": "ok", "output": "pong"}
+  else:
+    result = {"status": "error", "output": f"未知指令类型: {msg_type}"}
+
+  response = {
+    "type": "result",
+    "id": msg_id,
+    "status": result["status"],
+    "output": result.get("output", "")
+  }
+  try:
+    await ws.send(json.dumps(response))
+  except Exception as e:
+    print(f"[C3] 发送响应失败: {e}")
+
+
+# ================= 主循环 =================
+async def run():
+  """异步主循环（连接、注册、心跳、消息处理、自动重连）"""
+  serial = get_serial()
+  dongle_id = get_dongle_id()
+  git_branch = get_git_branch()
+
+  print(f"[C3 Director Client] 启动 serial={serial} branch={git_branch}")
+
+  while True:
+    try:
+      async with websockets.connect(
+        SERVER_URL,
+        ping_interval=20,
+        ping_timeout=15
+      ) as ws:
+        print(f"[C3] ✅ 已连接服务器")
+
+        # 注册（带上分支信息）
+        register_msg = json.dumps({
+          "type": "register",
+          "serial": serial,
+          "dongle_id": dongle_id,
+          "git_branch": git_branch
+        })
+        await ws.send(register_msg)
+        print(f"[C3] 已注册: {serial} branch={git_branch}")
+
+        async def heartbeat():
+          while True:
+            await asyncio.sleep(HEARTBEAT_INTERVAL)
+            try:
+              await ws.send(json.dumps({"type": "heartbeat"}))
+            except Exception:
+              break
+
+        async def receiver():
+          async for message in ws:
+            try:
+              data = json.loads(message)
+              await handle_message(data, ws)
+            except json.JSONDecodeError:
+              pass
+            except Exception as e:
+              print(f"[C3] 处理消息出错: {e}")
+              traceback.print_exc()
+
+        await asyncio.gather(heartbeat(), receiver())
+
+    except websockets.ConnectionClosed:
+      print(f"[C3] 连接断开")
+    except ConnectionRefusedError:
+      print(f"[C3] 服务器拒绝连接")
+    except OSError as e:
+      print(f"[C3] 网络错误: {e}")
+    except asyncio.TimeoutError:
+      print(f"[C3] 连接超时")
+    except Exception as e:
+      print(f"[C3] 异常: {e}")
+      traceback.print_exc()
+
+    print(f"[C3] {RECONNECT_DELAY} 秒后重连...")
+    await asyncio.sleep(RECONNECT_DELAY)
+
+
+# ================= 入口 =================
+def main():
+  """
+  main() 函数 - 供 openpilot PythonProcess 调用
+  用法: PythonProcess("c3-client", "selfdrive.c3_client", always_run)
+  """
+  try:
+    asyncio.run(run())
+  except KeyboardInterrupt:
+    print("[C3] 客户端已停止")
+  except Exception as e:
+    print(f"[C3] 致命错误: {e}")
+    traceback.print_exc()
+
+
+if __name__ == "__main__":
+  main()