Exception handling improvment

[fvdcx]

When an exception happens during tool calls, if it's not MCPException, the error message is $"An error occurred invoking '{request.Params?.Name}'.";

The message doesn't contain too much info, why can't we print exception type and message as well?

[stephentoub]

why can't we print exception type and message as well

It's not about "printing". It's about what the server sends down to the client. Having arbitrary server-side exceptions, possibly containing arbitrary user and environmental data, be automically sent to the client, would be a significant security issue.

[fvdcx]

why can't we print exception type and message as well

It's not about "printing". It's about what the server sends down to the client. Having arbitrary server-side exceptions, possibly containing arbitrary user and environmental data, be automically sent to the client, would be a significant security issue.

Yeah, I understand it would a security issue if sending down to the client, actually my usage scenario is enterprise, the mcp server is only accessible with a small group of people inside company, returning detailed exception type & message(can promise no PII) would be great for people to report issue.

so the best way is to catch exception inside my tool?

[stephentoub]

so the best way is to catch exception inside my tool?

Yes. If you want it sent down to the client as an error, you can return a CallToolResult out of your tool, with its IsError set to true.