Libraries

class EngineClient:
    def __init__(self, url: str, key: str):
        self.url = url
        self.headers = {"X-Engine-Key": key}

    def execute(self, message: str, task_id: str) -> Iterator[Event]:
        """Yield events as the agent runs."""
        ...

    def replay(self, task_id: str, after: int = 0) -> Iterator[Event]:
        """Replay buffered events from a given timestamp."""
        ...

    def hitl_respond(self, task_id: str, answer: str) -> dict:
        """Answer a pending HITL request."""
        ...

    def health(self) -> dict:
        """Liveness check."""
        ...

    def memory_search(self, store: str, query: str, limit: int = 20) -> list:
        """Search a memory store."""
        ...

    def feedback(self, task_id: str, feedback_type: str, **kwargs) -> dict:
        """Submit feedback."""
        ...

class ResilientStream:
    def __init__(self, client: EngineClient, message: str, task_id: str):
        self.client = client
        self.message = message
        self.task_id = task_id
        self.last_ts = 0

    def __iter__(self):
        try:
            for event in self.client.execute(self.message, self.task_id):
                self.last_ts = event["timestamp"]
                yield event
        except (ConnectionError, ReadTimeout):
            yield from self._replay()

    def _replay(self):
        for event in self.client.replay(self.task_id, after=self.last_ts):
            self.last_ts = event["timestamp"]
            yield event