What if you don't need MCP at all?

What I've started experimenting with and will continue to explore is to have project-specific MCP tools.

I add MCP tools to tighten the feedback loop. I want my Agent to be able to act autonomously but with a tight set of capabilities that don't often align with off-the-shelf tools. I don't want to YOLO but I also don't want to babysit it for non-value-added, risk-free prompts.

So, when I'm developing in go, I create `cmd/mcp` and configure a `go run ./cmd/mcp` MCP server for the Agent.

It helps that I'm quite invested in MCP and built github.com/ggoodman/mcp-server-go, which is one of the few (only?) MCP SDKs that let you scale horizontally over https while still supporting advanced features like elicitation and sampling. But for local tools, I can use the familiar and ergonomic stdio driver and have my Agent pump out the tools for me.

Horizontal scaling of remote MCP Servers is something the spec is sadly lacking any recognition around. If you've done work in this space, bravo. I've been using a message bus to decouple the HTTP servers from the MCP request handlers. I'm still evolving the solution, but it's been interesting so far.

This is the interface I landed on to make pluggable 'session hosts': https://github.com/ggoodman/mcp-server-go/blob/b8216cc1830ad...

It goes a tad beyond the spec minimum because I think it's valuable to be able to persist some small KV data with sessions and users.