SSE auto ping

[michalbogacz]

It's easy to lost connection between MCP server and agent. This issue is faced by many people who create MCP server.
One way to keep connection on server side is implemented heartbeat. Examples of how this was approached in different projects:

Scala Metals
https://github.com/scalameta/metals/blob/39146132ddf16e827e3792c38eef0435b2a5e2f3/metals/src/main/scala/scala/meta/internal/metals/mcp/MetalsMcpServer.scala#L105

Rust SDK
modelcontextprotocol/rust-sdk#74

I think it would be useful for people implementing MCP server to have some example how to do it with chimp (or even better to have some convenient abstraction).

[adamw]

Currently chimp implements only the HTTP transport, where the SSE component is optional (and currently unused). For the tools/list and tool/call functionality, it is not needed. As every invocation is an HTTP POST call, I don't think a separate keep-alive mechanism is necessary?

See the spec: https://modelcontextprotocol.io/docs/concepts/transports#streamable-http

[baldram]

Hey, in this discussion you've mentioned that the SSE component is optional (and currently unused). Also, MCP deprecated SSE and adopted Streamable HTTP. This might resolve some of the connection issues discussed here.

My questions:

1. Is the existing SSE component a foundation for implementing Streamable HTTP support in Chimp?

2. What's the current recommended approach for implementing streaming responses with Chimp? Specifically, if I want my MCP server to support progressive results and send response chunks in real-time?

My use case: I'm implementing an MCP server that queries LLM model and needs to stream the generated tokens progressively as they arrive, rather than waiting for the complete response. This requires sending chunks from the LLM in real-time to provide a better user experience.

Any guidance on the current state of streaming support in Chimp would be appreciated!

[adamw]

Unfortunately Chimp currently does not support streaming - only "basic" request-response tools. But we should get to implementing this at some point :)

[jamesward]

Related... I've been asked to support SSE in the javadocs.dev MCP server. jamesward/javadoccentral#131

Is this possible today with Chimp?

[adamw]

@jamesward Hm I would have to debug, but I had the impression that just connecting an old MCP client which uses the SSE endpoint, returning the data (but not starting an SSE stream) would "just work". For the SSE version, the streaming was always optional. But maybe there's more to it. So today - it's not possible.

[adamw]

@cheleb I saw you open & close another issue on the same subject, is there something that doesn't work with chimp as you'd like it to? A failing use-case is always useful :)

[cheleb]

Hi @adamw, AFAIU chimp only support http transport for MCP. And only Cursor still support it AFAIK. I close this ticket because this was already known, and commented in the referenced issue.

I using and <3 Kilocode, that should support Streamable http or SSE.