# _child URL: /milo-cli/api/milo/_child/ Section: milo Description: Persistent child process for MCP gateway communication. --- > For a complete page index, fetch /milo-cli/llms.txt. Open LLM text (/milo-cli/api/milo/_child/index.txt) Share with AI Ask Claude (https://claude.ai/new?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2F_child%2Findex.txt) Ask ChatGPT (https://chatgpt.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2F_child%2Findex.txt) Ask Gemini (https://gemini.google.com/app?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2F_child%2Findex.txt) Ask Copilot (https://copilot.microsoft.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fmilo-cli%2Fapi%2Fmilo%2F_child%2Findex.txt) Module # `_child` Persistent child process for MCP gateway communication. 1Class ## Classes `ChildProcess` 12 ▼ A persistent child process that speaks JSON-RPC on stdin/stdout. Thread-safe: a lock serializes al… A persistent child process that speaks JSON-RPC on stdin/stdout. Thread-safe: a lock serializes all calls to the same child. Auto-reconnects if the child process dies. #### Methods `ensure_alive` 0 ▼ Spawn or reconnect if the child process is dead. `def ensure_alive(self) -> None` `send_call` 3 `dict[str, Any]` ▼ Send a JSON-RPC request and return the result. Thread-safe. *timeout* override… `def send_call(self, method: str, params: dict[str, Any], *, timeout: float | None = None) -> dict[str, Any]` Send a JSON-RPC request and return the result. Thread-safe. timeout overrides the instance`request_timeout`for this call. ##### Parameters Name Type Description `method` `—` `params` `—` `timeout` `—` Default:`None` ##### Returns `dict[str, Any]` `fetch_tools` 0 `list[dict[str, Any]]` ▼ Fetch tools/list from the child process. `def fetch_tools(self) -> list[dict[str, Any]]` ##### Returns `list[dict[str, Any]]` `is_idle` 0 `bool` ▼ Check if the child has been idle longer than idle_timeout. `def is_idle(self) -> bool` ##### Returns `bool` `kill` 0 ▼ Kill the child process. `def kill(self) -> None` Internal Methods 7 ▼ `__init__` 4 ▼ `def __init__(self, name: str, command: list[str], *, idle_timeout: float = 300.0, request_timeout: float = 30.0) -> None` ##### Parameters Name Type Description `name` `—` `command` `—` `idle_timeout` `—` Default:`300.0` `request_timeout` `—` Default:`30.0` `_spawn` 0 ▼ Start the child process with persistent pipes. `def _spawn(self) -> None` `_ensure_initialized` 0 ▼ Send initialize if not already done. `def _ensure_initialized(self) -> None` `_graceful_kill` 0 ▼ SIGTERM with grace period, then SIGKILL if needed. Must be called while holdin… `def _graceful_kill(self) -> None` SIGTERM with grace period, then SIGKILL if needed. Must be called while holding`self._lock`. `_write_line` 1 ▼ Write a line to the child's stdin. `def _write_line(self, line: str) -> None` ##### Parameters Name Type Description `line` `—` `_read_response` 2 `dict[str, Any]` ▼ Read frames until the response matching *req_id* arrives. `def _read_response(self, req_id: int, *, timeout: float | None = None) -> dict[str, Any]` ##### Parameters Name Type Description `req_id` `—` `timeout` `—` Default:`None` ##### Returns `dict[str, Any]` `_read_line` 1 `str` ▼ Read a line from the child's stdout with timeout. Uses a background thread so … `def _read_line(self, *, timeout: float | None = None) -> str` Read a line from the child's stdout with timeout. Uses a background thread so we can enforce a deadline even when the child blocks without writing a newline. ##### Parameters Name Type Description `timeout` `—` Default:`None` ##### Returns `str`