Have any of you here spent any time with MCPs at all? I've just started building an MCP client into this app i'm working on, and it hit me that this could be what enables a lot more of end user modification of programs and a version of Malleable software...though not completely malleable. You don't have to interact with them through a conversational or agentic interface, you can just treat them like RPCs, and if you set up standardized integration points into your application, users can build all types of customizations for at the very least the objects or metaphors within your system

I do something like that in https://gloodata.com/ not strictly MCPs (since they didn't existed when I started) but the idea is the same

Oh very cool! Yeah this looks a lot like what I have in mind...are you defining the available visualizations inside Gloodata or do the extensions provide that too?

I am massively into agents calling tools in a loop now. I replicated that blog and they are dead on about how crazy it simplifies AI integration. Its the tools that are important, and the agentic loop, and how that isolates the vague AI bit from the engineered determinist tool design part. I did a talk yesterday on it (slides) MCP is a tool discovery service I don't personally see it as that important unless you need your product to somehow integrate with random data sources (might be true for tool-for-thought but in general its not the main character for me).

@Scott the visualizations are available in gloodata, the extensions returns data describing what they want to show

@Tom Larkworthy yeah I'm looking at MCP a little differently and not from an agent/ai calling perspective, but more that its this pattern that enables you to extend your application in other ways that don't rely on LLMs in the loop (though they can be). Similar to what Mariano shared. I'm working on this Product/Task management app, and just realized we can use the MCP pattern to allow people to add new functionality without much code on our part (add the Github or Asana MCP server and integrate with their services) or allow users to create new functionality in a plugin-like way using the same protocol...

but the response of a tool is a single unstructured string. I guess thats useful for some human in the loop things or text based workflows but it doesn't seem super general.

thats the thing, it doesn't have to be unstructured

ok string + mimeType. I think you can embed your own mini DSL in your responses but nothing else can leverage it. There is no response API schema description that I know of, is there? The tool arguments have a OpenAPI schema definition but I don't think there is a corresponding one to the tool or resource output (maybe there is ?)

Yeah, there isn't at the moment and I have to imagine it will be coming soon. But there are a few other options beyond your own mini dsl (which would still count as context for any service that is actually using it, you'd just assign some additional meaning to it and could turn it into a tool call internally). You could make your MCP servers both server and client to your main app (which itself is also an MCP server and client) making tool calls in both directions Or if you want to bring another llm into the loop, filter the MCP server's response through a tool calling llm to convert it into the DSL/tool call format for your main app 😉

yeah I guess tools are a bit like CLI commands, you have certain arguments to invoke them and then they do some side effects and then vomit out some stdout which is human readable and thats quite useful, even if the response is just "ok"

Wow, looks like structured tool outputs were released as we were talking about them: https://x.com/chu_onthis/status/1935433647206830428?s=46&t=sAqv4O8SV8AEgeXTXGaORg

I just back to post the same thing! Lol. Yeah pretty cool