Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

MCP Apps: Extending servers with interactive user interfaces

blog.modelcontextprotocol.io

Post reply on HN
Print view View original

11–20 of 124 posts

Re: MCP Apps: Extending servers with interactive user interfaces

#11

Post by felixrieseberg »

Disclosure: I work at Anthropic, have worked on MCP

I also think this is pretty big. I think a problem we collectively have right now is that getting MCP closer to real user flows is pretty hard and requires a lot of handholding. Ideally, most users of MCP wouldn't even know that MCP is a thing - the same way your average user of the web has no idea about DNS/HTTP/WebSockets. They just know that the browser helps them look at puppy pictures, connect with friends, or get some work done.

I think this is a meaningful step in the direction of getting more people who'll never know or care about MCP to get value out of MCP.

Re: MCP Apps: Extending servers with interactive user interfaces

#12

Post by iLoveOncall »

felixrieseberg wrote: post #11

Disclosure: I work at Anthropic, have worked on MCP I also think this is pretty big. I think a problem we collectively have right now is that getting MCP closer to real user flows is pretty hard and requires a lot of handholding. Ideally, most users of MCP wouldn't even know that MCP is a thing - the same way your average user of the web has no idea about DNS/HTTP/WebSockets. They just know that the browser helps the…

I wonder how long it'll take you to figure out that you're trying to reinvent deterministic APIs.

Re: MCP Apps: Extending servers with interactive user interfaces

#14

Post by stingraycharles »

iLoveOncall wrote: post #5
mercury24aug wrote: post #2

Looks like OpenAI, Anthropic, and the MCP-UI team actually worked together on a common standard for MCP Apps: https://blog.modelcontextprotocol.io/posts/2025-11-21-mcp-ap... Honestly, I think the biggest friction for MCP adoption has been how un-userfriendly it is. It’s great for devs, but not the average users. Users don't always want to chat, sometimes they just want to click a button or adjust a slider. This feels…

Who wants a button that has indeterministic actions?

Unless the MCP server itself has an LLM call inside of it (rare), the MCP server is pretty deterministic. It’s the AI that invokes it that’s actually indeterministic, but the user is already using that.

Re: MCP Apps: Extending servers with interactive user interfaces

#15

Post by oulipo2 »

I'm not sure I get why we need something specific like MCP-UI? why wouldn't "just another tool" do exactly the same?

Eg you present a "display-graph-chart" tool as a MCP tool, and the agent calls it, it doesn't need to adhere to any protocol except the basic existing MCP protocol, and the UI that's used to interact with the agent would know the best presentation (show it as an embedded HTML graph if in a web ui, show it as a ascii chart if in a terminal, etc)?

Is the idea just to standardize the "output format" of the tool so that any agent UI could display stuff in the same way? so that one tool could work with any agent display?

Re: MCP Apps: Extending servers with interactive user interfaces

#16

Post by stingraycharles »

iLoveOncall wrote: post #12
felixrieseberg wrote: post #11

Disclosure: I work at Anthropic, have worked on MCP I also think this is pretty big. I think a problem we collectively have right now is that getting MCP closer to real user flows is pretty hard and requires a lot of handholding. Ideally, most users of MCP wouldn't even know that MCP is a thing - the same way your average user of the web has no idea about DNS/HTTP/WebSockets. They just know that the browser helps the…

I wonder how long it'll take you to figure out that you're trying to reinvent deterministic APIs.

What is indeterministic about MCP servers? Most of them follow fairly simple rules, eg an MCP server to interact with Slack gives pretty deterministic responses to requests.

Or are you confusing the LLM / MCP client invoking the tools being non-deterministic?

Re: MCP Apps: Extending servers with interactive user interfaces

#17

Post by neoden »

iLoveOncall wrote: post #12
felixrieseberg wrote: post #11

Disclosure: I work at Anthropic, have worked on MCP I also think this is pretty big. I think a problem we collectively have right now is that getting MCP closer to real user flows is pretty hard and requires a lot of handholding. Ideally, most users of MCP wouldn't even know that MCP is a thing - the same way your average user of the web has no idea about DNS/HTTP/WebSockets. They just know that the browser helps the…

I wonder how long it'll take you to figure out that you're trying to reinvent deterministic APIs.

MCP is already deterministic. What's huge about it is that it has automatic API discovery and integration built-in. It's a bit rough yet but I think we will only see how it's getting improved more and more.

Re: MCP Apps: Extending servers with interactive user interfaces

#18

Post by mindwok »

It'll be interesting to see how this goes, but my first impression is that it's actually not where we want to go. One of the cool things about MCP (or even just tool calling) is that the LLM on top of a tool provides a highly flexible and dynamic interface to traditionally static tools.

I love being able to type "make an iptables rule that opens 443" instead of having to dig out the man page and remember how to do that. IMO the next natural extension of this is giving the LLM more capability to generate user interfaces so I can interact with stuff exactly bespoke to my task.

This on the other hand seems the other way round, it's like bolting a static interface onto the LLM, which could defeat the purpose of the LLM interface layer in the first place right?

Re: MCP Apps: Extending servers with interactive user interfaces

#20

Post by ivape »

mindwok wrote: post #18

It'll be interesting to see how this goes, but my first impression is that it's actually not where we want to go. One of the cool things about MCP (or even just tool calling) is that the LLM on top of a tool provides a highly flexible and dynamic interface to traditionally static tools. I love being able to type "make an iptables rule that opens 443" instead of having to dig out the man page and remember how to do th…

I personally don’t see why developers should just add tons of functionality to any model for free like this. Some of these MCPs are pretty good, and I was a little shocked how much functionality developers released for free to drop into something like Claude. Either developers are stupid or there really is no market yet.
Post reply on HN