How to control when timeout occurs?

[andybrandt]

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Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
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Your Question

Using Python SDK how can I set how long MCP implementation should wait for the response from an external resource? I am building an mcp server which talks to a resource that sometimes takes about 20-40 seconds to respond, so the response is never returned because a timeout occurs. Looked at the docs but I don't see indication how to do this.

[jspahrsummers]

Timeouts are controlled on the client side, not the server side. This is necessary because a misbehaving server may never respond (even if it "meant to").

You may want to consider prefetching the resource, or introducing some kind of multi-step loading, like:

1. Client sends a request. Loading begins, server responds with "in progress."
2. Client polls until loading is complete and/or server sends a notification that loading completed.
3. Client sends a final request, and gets back the actual resource.

Though this question did make me think that we could support auto-extending timeouts when progress notifications are used, which doesn't currently happen.

[andybrandt]

Thanks tons for the response about timeouts!

Reading the MCP Python SDK documentation, I see examples of progress tracking using request_context.meta.progressToken, but when I tried this it turned out these objects (context and progressToken) are None when accessed through server.request_context.

Is this because progress notification support needs to be implemented on the client side first? The documentation suggests this functionality but if I understand correctly, I should focus on implementing the multi-step approach you suggested instead of trying to use progress notifications at this point?

[jspahrsummers]

Hmm, progress notifications from the server to the client should work. Perhaps @dsp-ant knows more here 🙏

[andybrandt]

Well, they do not allow to keep the session alive - the timeout still occurs.
So for now I solved it by sending back to using AI information that the response is not yet ready, Claude is smart enough to wait a bit and try again.