feat: support customize Header and improve validations

[greenhat616]

• Use clap to parse env directly
• Support customize headers for SSE/StreamableHttp transport
• Support specify TransportType directly
• validate Url while parsing Args

[josevalim]

Thank you @greenhat616! Can you please explain your use cases? The reason we ask is because we moved most of our servers to use streamable http and we hope we won't need the proxy for much longer, so we are worried about adding features to the project when we may not maintain it for much longer.

[greenhat616]

@josevalim We just migrated to streamable http too. To compatibale with Claude Desktop, we have to look for a stdio proxy to make it run on local mcp servers.

FYI, Claude Desktop only support SSE/Streamable HTTP MCP Server on Settings / Connector, which is only available for Pro/Max or Ent users. The local MCP Servers only support stdio servers.

• https://thesof.medium.com/bridging-mcp-transports-turning-an-stdio-server-into-sse-and-the-other-way-around-da23a36e074a

[nzjrs]

I ran into this limitation today too. I need arbitrary header support to bypass a proxy to access and internal resource, externally.

[SteffenDE]

The code looks good to me, but just to align expectations: we maintain this proxy for the Tidewave MCP servers that are meant to run on the same machine. The features we have (replying init for reconnects) are very much focused on that specific use case. Adding features that are not needed for this are therefore not a priority for us and as José mentioned we may very well archive this repository once we deem it unnecessary for our use case.

If you want to provide a more generalized MCP proxy based on this project, you're more than welcome to do so in a fork as we're unlikely to accept many new features here.