Show HN: A MCP server and client implementing the latest spec

70 pointsposted 21 hours ago
by init0
(github.com)

27 Comments

jamesblonde

17 hours ago

Protocol version in the readme is Full MCP 2025-03-26 specification support

in the code it is "protocolVersion": "2024-11-05"

https://github.com/hemanth/paws-on-mcp/blob/main/src/mcp_cli...

cfors

17 hours ago

The README is 100% just autogenerated by Claude. It looks like every README generated from these tools.

Can’t speak for the code since I haven’t peaked into it

jamesblonde

16 hours ago

I thought it was a bit verbose - lots of repetition. I didn't realize how extensive claude/cursor generated READMEs were.

owebmaster

12 hours ago

The README is a great overview of the MCP features. This is terribly derisive.

manojlds

18 hours ago

Almost no client, including Claude Dekstop, implements Sampling.

I was so excited to see if I can create a server that used sampling and quickly figured out I can't use it anywhere. Funnily Windsurf hangs forever if you use sampling.

ericol

16 hours ago

I've been thinking about this ever since I heard that is defined in the protocol.

I think the biggest issue is that it can create loops in the flow of programs that would burn through usage quotas pretty fast. It could also allow for "impersonating" the client what opens up a lot of possibilities.

But yeah, the fact that Claude doesn't even implement this is... telling.

auggierose

16 hours ago

Yeah, that is the reason it is not there, I guess, you could then really implement anything just with a flat rate.

auggierose

16 hours ago

Yes, no sampling, last time I tried a few weeks ago. Have you tried with the latest Claude Desktop (0.10.14)?

baalimago

18 hours ago

The fact that this is an achievement is a testament to how bloated the MCP protocol/spec already is.

Will be interesting to see how many days it'll take before the implementation no longer is the latest

tomashubelbauer

15 hours ago

I don't disagree, but the first sentence of your post happens to be true for very many specs/protocols I know of and have implemented in the past. And it is not just communication protocols. Take PDF for example. The world practically runs on it, yet the file format is horrid. The real standard seems to be that standards are bloated by default.

Spivak

13 hours ago

Right but MCP is a brand new protocol which is at its core JSON-RPC formatted messages and a few verbs. It doesn't actually do much. The main things are tool definitions which is just a JSON schema describing a function call and resources which a is a wisp of a filesystem.

tomashubelbauer

13 hours ago

Fair, thought I have a feeling MCP will actually grow to do much more. I wouldn't disagree with the sentiment that it is too bloated too soon, but I also feel like it is destined to be bloated, because the technology it is targeting is sort of a moving target itself. Of course with proper versioning, this is easeable, deprecate stuff that turned out to be the wrong turn and cut major versions or introduce extensions to the protocol when new stuff is on the scene, but then you're liable to find yourself in an XMPP-style situation where no one implements the standard and extensions wholly, because it is so complex.

LeonidBugaev

16 hours ago

It does not implement the Auth :)

(mcp auth is terrible btw)

WXLCKNO

14 hours ago

For my app I'm bypassing MCP auth and doing the regular oauth2 flow to connect users to external apps.

Then I pass the stored oauth token directly to my (private) MCP servers alongside a bearer token.

pcwelder

15 hours ago

Tool annotations are missing. (Are they of any use though?)

jhosft

16 hours ago

That README.md is so vibed with all the emojis and self-proofed comments. One day we’re going to look back on code written in June 2025 and laugh. The code works, but man does Claude 4 pump itself up.

esafak

14 hours ago

The median code base it is trained on must be like that.

hammyhavoc

10 hours ago

University student work y'say?

hammyhavoc

10 hours ago

> The code works

Need a phat asterisk after it.

josephg

14 hours ago

What is MCP? I’ve never heard of it.

buonu

an hour ago

Aka controller or middleware

Bit of software between client and backend model to model client requests to

It can look like Anthropics model or it can be your own. It’s verbose semantics to describe a little bit of source code.

Obfuscation of simple loops and scripts is software industries main product