HKUDS/nanobot · error · SessionMessageError

source session was not found

Error message

source session was not found

What it means

Error "source session was not found" thrown in HKUDS/nanobot.

Source

Thrown at nanobot/agent/tools/session_messages.py:229

        content: str,
        expect_reply: bool,
        reply_timeout_seconds: int | None = None,
    ) -> str:
        timeout_seconds = self._validate_reply_timeout(expect_reply, reply_timeout_seconds)
        try:
            target_name = normalize_session_handle(target_handle)
        except ValueError as exc:
            raise SessionMessageError(str(exc)) from exc
        target = await asyncio.to_thread(self._handles.resolve, target_name)
        if target is None:
            raise SessionMessageError(f"session @{target_name} was not found")

        source = await asyncio.to_thread(
            self._handles.handle_for_session,
            source_session_key,
        )
        if source is None:
            raise SessionMessageError("source session was not found")
        envelope: SessionMessageEnvelope = {
            "message_id": uuid4().hex,
            "created_at_ms": int(time.time() * 1000),
            "expect_reply": expect_reply,
            "source_handle": source.name,
            "source_session_key": source.session_key,
            "target_session_key": target.session_key,
        }
        reverse_wait_key = (target.session_key, source.session_key)
        wait_key = (source.session_key, target.session_key)

        async with self._send_lock:
            now = self._clock()
            sent_at = self._sent_at.setdefault(source.session_key, deque())
            cutoff = now - _RATE_LIMIT_WINDOW_SECONDS
            while sent_at and sent_at[0] <= cutoff:
                sent_at.popleft()
            if len(sent_at) >= self._max_messages_per_minute:

View on GitHub (pinned to 42f37dc4c0)

When it happens

Trigger: Thrown at nanobot/agent/tools/session_messages.py:229 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of HKUDS/nanobot@42f37dc4c0 (2026-08-26). Data as JSON: /api/errors/493a4a4e4120c086. Report an issue: GitHub.