Show HN: Mcp-use – Connect any LLM to any MCP • Hacker News Board

Re: Show HN: Mcp-use – Connect any LLM to any MCP

#71

Post by MutedEstate45 » Mon, Aug 04, 2025, 4:11 AM UTC

farkin88 wrote: post #70

The prod-readiness concerns are fair, but mcp-use fills a real gap in the MCP stack: orchestration across many servers with far less boilerplate than the official SDK. Even if the agent is as another commenter fairly pointed out, just a LangChain wrapper, the six-line setup and server manager are a nice DX upgrade. What’s still missing is structured error semantics. Right now, when a tool explodes the LLM only sees a…

Thanks for the mention! I'm the author of Mcp-error-formatter, which was mentioned above. Exactly right about the client/server complexity. I've been working on this exact problem. Client-side heuristics can catch timeouts and HTTP codes, but nuanced business logic errors need server cooperation.

The interesting part is dual error representation: devs need full stack traces for debugging, but LLMs need clean structured metadata for retry decisions. Plus you want error telemetry flowing to observability systems.

Question for the mcp-use authors: How do you handle error propagation in multi-server setups? If Server A times out but Server B is healthy, does the agent know which server failed and whether to retry or switch servers? And are you capturing error patterns to identify flaky servers or consistently failing tool calls? The retry orchestration across multiple MCP servers seems like a really interesting problem.

Re: Show HN: Mcp-use – Connect any LLM to any MCP

#72

Post by pzullo » Tue, Aug 05, 2025, 3:12 AM UTC

farkin88 wrote: post #70

The prod-readiness concerns are fair, but mcp-use fills a real gap in the MCP stack: orchestration across many servers with far less boilerplate than the official SDK. Even if the agent is as another commenter fairly pointed out, just a LangChain wrapper, the six-line setup and server manager are a nice DX upgrade. What’s still missing is structured error semantics. Right now, when a tool explodes the LLM only sees a…

Hey thanks for the comment, the work from https://github.com/bjoaquinc/mcp-error-formatter is great. I will definitely put some version of this into one of the next releases. Just opened an issue mentioning this thread.

The problem with the package above is that it is server side, and I think it should be. Server is the one that knows (has responsibility to know) if a tool is retryable and has informations about the error, and fairly so.

I see though how some sort of improved error formatting could be introduced in the client as well, but it shouldn't contain any logic about the error, rather format the error in the best way possible (in the direction in which it is best understandable by LLMs).

Re: Show HN: Mcp-use – Connect any LLM to any MCP

#73

Post by pzullo » Tue, Aug 05, 2025, 3:26 AM UTC

MutedEstate45 wrote: post #71

farkin88 wrote: post #70

The prod-readiness concerns are fair, but mcp-use fills a real gap in the MCP stack: orchestration across many servers with far less boilerplate than the official SDK. Even if the agent is as another commenter fairly pointed out, just a LangChain wrapper, the six-line setup and server manager are a nice DX upgrade. What’s still missing is structured error semantics. Right now, when a tool explodes the LLM only sees a…

Thanks for the mention! I'm the author of Mcp-error-formatter, which was mentioned above. Exactly right about the client/server complexity. I've been working on this exact problem. Client-side heuristics can catch timeouts and HTTP codes, but nuanced business logic errors need server cooperation. The interesting part is dual error representation: devs need full stack traces for debugging, but LLMs need clean structur…

Hey, awesome work with the error formatter, as explained above I think error creation falls more under the server responsibilities if it contains any logic about the error (e.g. is retryable). It would be interesting to hear your opinion on a format for LLM side errors.

Regarding the multi server failure case: (without server manager) today if one of the server dies the agent will keep going, I do not think this is a particularly thought through decision, probably the client should error out, or let the agent know that the server is dead. (with server manager) the agent will try to connect to the dead server, get an error, possibly retry, but if the server keeps being unable to connect to, the agent will eventually bail. Indeed it is an interesting problem. How do you see the responsibility split here ?

Regarding the flakyness, ultimate dream, but requires some more work, I think that monitoring this is something that the client has a privileged position of doing, we will do it for sure. I think this is going to be great feedback for companies building servers. Happy to coordinate on ideas on how to do this best.