Hi,
While testing agent builder I get it to hit my local environment with ngrok.
I find that if the mcp route doesn’t exist on the first call of the day it is not usable till the next day even when I get the route correct.
This tells me that openai is caching the route as invalid and doesn’t expire it for around 24 hours.
My code as per the MCP spec 405s the get requests (the spec allows for either). I will still see the get requests come in from open ai but not the post requests. This tells me that the get requests aren’t cached.
So to simplify:
- On the first login of the day if the route doesn’t exist open ai will stop doing post requests.
- This is likely because openai caches the post requests as invalid and won’t do them.
- Open ai also caches valid post requests. If I do a request which works then remove it it will fail but when I add it back it succeeds. This makes it harder to replicate.
My current fix is to REALLY make sure I’m on the correct branch at the start of the day and to not do ANY mcp calls unless it is 100% up and running. However this could also lead to pretty large issues in a prod environment.
Open ai should remove this caching on post requests.