Sync tool calls are blocking the event loop?

[pcoccoli]

I have a mix of custom toolkits; some are async and some are sync. I've set PYTHONASYNCIODEBUG=1 in my environment to check for async issues, and I see a lot of warnings like these:

2025-09-09 15:10:57 - WARNING - Executing <Task finished name='Task-38' coro=<Model.arun_function_call() done, defined at /Users/paul.coccoli/.pyenv/versions/3.12.4/envs/myenv-3.12.4/lib/python3.12/site-packages/agno/models/base.py:1368> result=(True, <agno.utils.t...t 0x3084637d0>, FunctionCall(...', error=None)) created at /Users/paul.coccoli/.pyenv/versions/3.12.4/lib/python3.12/asyncio/tasks.py:695> took 0.526 seconds

I'm using agno in a FastAPI microservice, so that message means I can't answer any other requests for over half a second. That's a problem. Do all my tools need to be async?

[anuragts]

Hey @pcoccoli, can you try with making all the tools async and check if issue persists. Can you also share your agent config, so we can debug locally on our end.

[pcoccoli]

Making the tools async does make it go away; I have done this now. I can't share my code, but I will try to come up with a minimal example that demonstrates the issue.