fix: bootstrap serial monitor on UART open

tools/hwlab-node.py

@@ -811,7 +811,21 @@ class NodeOpsExecutor:
             command.extend([*(["-p", port] if port else []), *(["-b", str(baud)] if baud else [])])
         output = self._spawn_output(command, serial_dir, timeout_ms)
         body = self._parse_json(output.get("stdout"))
-        return {**output, "ok": output.get("ok") and body.get("success") is True, "bindingSource": "serial-monitor-cli", "port": port or None, "baudRate": baud, "response": body or None}
+        server_start = None
+        if action == "start" and self._serial_server_unreachable(body):
+            server_start = self._spawn_output([*command_base, "server", "start"], serial_dir, timeout_ms)
+            server_body = self._parse_json(server_start.get("stdout"))
+            server_start = {**server_start, "response": server_body or None}
+            if server_start.get("ok") and server_body.get("success") is True:
+                output = self._spawn_output(command, serial_dir, timeout_ms)
+                body = self._parse_json(output.get("stdout"))
+        return {**output, "ok": output.get("ok") and body.get("success") is True, "bindingSource": "serial-monitor-cli", "port": port or None, "baudRate": baud, "response": body or None, "serverStart": server_start}
+
+    def _serial_server_unreachable(self, body: dict) -> bool:
+        data = body.get("data") if isinstance(body.get("data"), dict) else {}
+        request = data.get("request") if isinstance(data.get("request"), dict) else {}
+        diagnosis = data.get("diagnosis") if isinstance(data.get("diagnosis"), dict) else {}
+        return body.get("success") is False and (request.get("code") == "ECONNREFUSED" or diagnosis.get("status") == "not_running")
 
     def _uart_write(self, args: dict) -> dict:
         data = str(args.get("data") or "")

tools/hwpod-node.test.ts

@@ -396,6 +396,40 @@ print(json.dumps({"results": results, "commands": executor.commands}))
   assert.deepEqual(result.results.map((item: any) => item.status), ["completed", "completed", "completed"]);
 });
 
+test("python hwpod-node starts an unreachable serial-monitor server before opening UART", () => {
+  const script = `
+import importlib.util, json, logging
+spec = importlib.util.spec_from_file_location("hwlab_node", "tools/hwlab-node.py")
+module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(module)
+class Executor(module.NodeOpsExecutor):
+    def __init__(self):
+        super().__init__({"nodeId": "node-test"}, logging.getLogger("test"))
+        self.commands = []
+    def _spawn_output(self, command, cwd, timeout_ms):
+        self.commands.append(command)
+        if command[-2:] == ["server", "start"]:
+            body = {"success": True}
+        elif len(self.commands) == 1:
+            body = {"success": False, "data": {"request": {"code": "ECONNREFUSED"}, "diagnosis": {"status": "not_running"}}}
+        else:
+            body = {"success": True}
+        return {"ok": True, "stdout": json.dumps(body), "stderr": "", "exitCode": 0}
+executor = Executor()
+result = executor._execute_op({"opId": "open", "op": "io.uart.open", "args": {"workspacePath": ".", "port": "COM4", "baudRate": 921600, "serialMonitorCommand": ["serial-monitor"]}})
+print(json.dumps({"result": result, "commands": executor.commands}))
+`;
+  const completed = spawnSync("python3", ["-c", script], { cwd: process.cwd(), encoding: "utf8" });
+  assert.equal(completed.status, 0, completed.stderr);
+  const result = JSON.parse(completed.stdout);
+  assert.equal(result.result.status, "completed");
+  assert.deepEqual(result.commands, [
+    ["serial-monitor", "monitor", "start", "-p", "COM4", "-b", "921600"],
+    ["serial-monitor", "server", "start"],
+    ["serial-monitor", "monitor", "start", "-p", "COM4", "-b", "921600"],
+  ]);
+});
+
 test("hwpod-node resolves Git for Windows when service PATH omits git", async () => {
   const result = await resolveHwpodNodeCommand("git", {
     platform: "win32",