hermes - 💡(How to fix) Fix send_message weixin: asyncio 'Future attached to a different loop' bug [1 comments, 2 participants]

Bug Description

The send_message tool fails with a cross-event-loop asyncio error when trying to send to Weixin:

Task <Task pending name='Task-1857' coro=<_send_to_platform() running at tools/send_message_tool.py:524>> got Future <Future pending> attached to a different loop

This happens every time send_message is invoked for Weixin, regardless of the message content.

Root Cause Analysis

Call chain:

1. send_message tool → _handle_send()
2. _run_async(_send_to_platform(...)) — since Hermes gateway has a running event loop, this takes the worker-thread path
3. Worker thread creates asyncio.new_event_loop() → worker_loop
4. worker_loop.run_until_complete(_send_to_platform())
5. Inside _send_to_platform, await _send_weixin(...) fails with the error above

Why it fails: The send_message_tool runs in the agent/LLM tool-execution context, NOT inside the gateway's async stack. When _run_async is called, asyncio.get_running_loop() returns the gateway's loop (which IS running), so the code takes the worker-thread path. But the error occurs inside _send_to_platform itself — not inside send_weixin_direct.

This suggests that either:

1. Some import-time side effect in gateway/platforms/weixin.py creates objects bound to the gateway loop, OR
2. The await _send_weixin() expression itself is where the cross-loop Future is encountered

Key observation: Even though send_weixin_direct was patched to always use the standalone aiohttp.ClientSession path (bypassing _LIVE_ADAPTERS), the error persists. This means the problem is not in send_weixin_direct — it's at the await _send_weixin() call site inside _send_to_platform at line 524.

Affected code path:

• tools/send_message_tool.py line ~524: return await _send_weixin(pconfig, chat_id, message, media_files=media_files)
• _send_weixin is an async def that imports and calls gateway.platforms.weixin.send_weixin_direct

Environment

• macOS (macOS-aarch64)
• Python 3.11 via uv
• Hermes Agent gateway running (hermes gateway run)
• Weixin platform connected

Current Workaround

None — the bug blocks all Weixin file sends via the send_message tool.

Suggested Fix

The _run_async function's worker-thread path is correctly isolating the coroutine to a fresh loop. The issue likely lies in how the from gateway.platforms.weixin import ... import interacts with module-level singletons or cached objects from the gateway's loop.

A proper fix should ensure that:

1. No module-level aiohttp.ClientSession, asyncio.Task, or asyncio.Event objects from the gateway loop are referenced when running in the worker thread's loop
2. Alternatively, lazy-import the weixin module INSIDE the worker thread to avoid pre-existing loop-bound objects