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whoknowsidont 12 hours ago

MCP was a really shitty attempt at building a plugin framework that was vague enough to lure people into and then allow other companies to build plugin platforms to take care of the MCP non-sense.

"What is MCP, what does it bring to the table? Who knows. What does it do? The LLM stuff! Pay us $10 a month thanks!"

LLM's have function / tool calling built into them. No major models have any direct knowledge of MCP.

Not only do you not need MCP, but you should actively avoid using it.

Stick with tried and proven API standards that are actually observable and secure and let your models/agents directly interact with those API endpoints.

jcelerier 5 hours ago | parent | next [-]

> LLM's have function / tool calling built into them. No major models have any direct knowledge of MCP.

but the major user interfaces for operating LLMs do and that's what matters

> Not only do you not need MCP, but you should actively avoid using it.

> Stick with tried and proven API standards that are actually observable and secure and let your models/agents directly interact with those API endpoints.

so what's the proven and standard API I can use to interact with ableton live? blender? unity3d? photoshop?

whoknowsidont 5 hours ago | parent [-]

>so what's the proven and standard API I can use to interact with ableton live? blender? unity3d? photoshop?

Do you think MCP helps you out here? Because I can't really think of any other reason why'd you ask this.

nilslice 4 hours ago | parent [-]

What do all of the links below have in common? Do you know of another way you can control all of those applications via LLMs? Computer use?

https://github.com/ahujasid/ableton-mcp

https://github.com/ahujasid/blender-mcp

https://github.com/CoplayDev/unity-mcp

https://github.com/mikechambers/adb-mcp

growt 3 hours ago | parent [-]

The mcp part is not essential for the actual controlling of the applications. You could “rip out” the mcp functionality and replace it with something else. The only reason why the authors chose mcp is most likely that it was the first and therefore most common plugin interface for llm tools.

TranquilMarmot 2 hours ago | parent | next [-]

Unfortunately, most standards that we end up with are only standard because they're are widely used and not because they are the best or they make the most sense.

theshrike79 2 hours ago | parent | prev | next [-]

MCP literally is the "something else", if you have a better idea in mind, now is the time to bring it out before the MCP train is going too fast to catch up.

Zetaphor 3 hours ago | parent | prev [-]

Isn't that the point they are making? MCP is useful because everyone is using it, not because it has a technical advantage over rolling your own solution. It won mindshare because of marketing and a large company pushing it.

I've actually taken to both approaches recently, using the mcp-client package to give me an interface to a wide array of prebuilt tools in my non-LLM application. I could have written or sourced 10 different connectors, or I can write one client interface and any tool I plug in shares the same standard interface as all the others.

didibus 5 hours ago | parent | prev | next [-]

> MCP was a really shitty attempt at building a plugin framework

Can you go more in depth? The protocol is relatively simple, what about it you feel is "shitty" as a plugin framework?

paulddraper 5 hours ago | parent [-]

The hate for MCP here is absurd.

It's JSON-RPC, with some descriptors.

And some comments about OAuth 2.

The value is in the consensus. You can make a tool that agents can connect to with no apriori knowledge.

whoknowsidont 5 hours ago | parent [-]

>It's JSON-RPC, with some descriptors.

That's not even true. It defines the lifecycle of tool calling.

JSON-RPC with some descriptors would have been fine and amazing.

pjmlp 23 minutes ago | parent | prev | next [-]

Fully agree, however we need to reach our KPIs and OKRs regarding AI adoption.

block_dagger 2 hours ago | parent | prev | next [-]

Perhaps you haven't used many MCP server, but those that I have used (GitHub, Atlassian, Glean, BuildKite, Figma, Google Workspace, etc) work very well. They teach an LLM how to do exactly what you're saying - "use the API standards...your models/agents directly interact with those API endpoints." Most MCP severs don't sit in between the LLM and the API endpoints, they just teach them how to use the tools and then the LLM calls the APIs directly as any HTTP client would. I find it works quite well and seems far better than manually maintaining rules or pointing at docs and installing CLI tools (like "gh" for GitHub) or using curl to interact with APIs from a terminal within a chat session.

timClicks 3 hours ago | parent | prev | next [-]

MCP is an example of "worse is better". Everyone knows that it's not very good, but it gets the job done.

cyanydeez 11 hours ago | parent | prev | next [-]

probably easier to just tell people: You want MCP? Add a "description" field to your rest API that describes how to call it.

That's all it's doing. Just plain ole context pollution. World could be better served by continuing to build out the APIs that exist.

blitzar 41 minutes ago | parent | next [-]

> World could be better served by continuing to build out the APIs that exist.

before LLM's and MCP the world was depreciating or locking down APIs

pests 6 hours ago | parent | prev | next [-]

Sometimes the actions you want to perform does not map cleanly into one or two API calls, or would be too messy to assume correct parsing. Maybe your UI is fine POSTing to /users and PUTing to /groups or whatever but giving the LLM a direct CreateUserAndAddToGroup action simplifies the task and keeps context cleaner.

jes5199 11 hours ago | parent | prev | next [-]

yesss, and OpenAI tried this first when they were going to do a “GPT store”. But REST APIs tend to be complicated because they’re supporting apps. MCP, when it works, is very simple functions

in practice it seems like command line tools work better than either of those approaches

CuriouslyC 10 hours ago | parent [-]

Command line tools are my preference just because they're also very useful to humans. I think providing agents function libraries and letting them compose in a repl works about as well but is higher friction due env management.

EagnaIonat 4 hours ago | parent | prev | next [-]

> Just plain ole context pollution.

It would normally be a second context window to figure out what tool / agent to run.

My only quibble with MCP is in the usual AI bandwagon people are implementing for FOMO than business value. My experience is likely anecdotal though.

mycall 8 hours ago | parent | prev | next [-]

Also, keep your api small as all the tool call, DTOs and user messages (e.g. workflow recipes) add up to big context windows and accuracy confusion, at least in the latest models. I hope that gets resolved.

tacticus 11 hours ago | parent | prev [-]

> Add a "description" field to your rest API that describes how to call it.

Isn't that swagger\grpc etc?

paulddraper 7 hours ago | parent | prev | next [-]

> No major models have any direct knowledge of MCP.

Claude and ChatGPT both support MCP, as does the OpenAI Agents SDK.

(If you mean the LLM itself, it is "known" at least as much as any other protocol. For whatever that means.)

whoknowsidont 6 hours ago | parent [-]

>it is "known" at least as much as any other protocol.

No. It is not. Please understand what the LLM's are doing. Claude nor ChatGPT nor any major model knows what MCP is.

They know how to function & tool call. They have zero trained data on MCP.

That is a factual statement, not an opinion.

Bockit 6 hours ago | parent | next [-]

This is probably a semantics problem. You’re right. The models don’t know how to mcp. The harness they run in does though (Claude code, Claude desktop, etc), and dynamically exposes mcp tools as tool calls.

whoknowsidont 6 hours ago | parent | next [-]

>dynamically exposes mcp tools as tool calls.

It doesn't even do that. It's not magic.

llbbdd 6 hours ago | parent | prev [-]

HN loves inventing semantics problems around AI. It's gotten really, really annoying and I'm not sure the people doing it are even close to understanding it.

choilive 6 hours ago | parent | prev | next [-]

That is an easily falsifiable statement. If I ask ChatGPT or Claude what MCP is Model Context Protocol comes up, and furthermore it can clearly explain what MCP does. That seems unlikely to be a coincidental hallucination.

whoknowsidont 6 hours ago | parent [-]

Training data =/= web search

Both ChatGPT and Claude will perform web searches when you ask them a question, which the fact that you got this confused is ironically topical.

But you're still misunderstanding the principle point because at some point these models will undoubtedly have access to that data and be trained on it.

But they didn't need to be, because LLM function & tool calling is already trained on these models and MCP does not augment this functionality in any way.

davidcbc 6 hours ago | parent [-]

Claude gives me a lengthy explanation of MCP with web search disabled

whoknowsidont 5 hours ago | parent [-]

Great! It's still irrelevant.

cookiengineer 5 hours ago | parent | prev | next [-]

> That is a factual statement,

I think most people, even most devs, don't actually know how crappy an MCP client is built, and that it's essentially an MITM approach and that the client sends the LLM on the other end a crappy pretext of what tools are mounted and how to call their methods in a JSON, and then tries to intelligently guess what response was a tool call.

And that intelligent guess is where it gets interesting for pentesting, because you cannot guess anything failsafe.

numpad0 6 hours ago | parent | prev | next [-]

(pedantry)it's something humans are talking about a lot, so up-to-date models do know about it...

whoknowsidont 6 hours ago | parent [-]

Most likely! It's hard to qualify which specific models and version I'm talking about because they're constantly being updated.

But the point is that function & tool calling was already built in. If you take a model from before "MCP" was even referenced on the web it will still _PERFECTLY_ interact with not only other MCP servers and clients but any other API as well.

3 hours ago | parent | prev | next [-]
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paulddraper 5 hours ago | parent | prev [-]

> They have zero trained data on MCP.

They have significant data trained on MCP.

> They know how to function & tool call.

Right. You can either use MCP to transmit those tool calls, or you can create some other interface.

whoknowsidont 5 hours ago | parent [-]

>They have significant data trained on MCP.

No they don't lol.

voidhorse 9 hours ago | parent | prev [-]

Yeah there's no there there when it comes to MCP. It's crazy to me that the world bought into the idea when the "spec" literally boils down to "have your server give the LLM some json". Just illustrates how powerful it is to attach names to things, especially in a hypestorm in which everyone is already frothing at the mouth and reason is hard to come by. Give people some word they can utter to help them sound like they're on the "bleeding edge" and they'll buy into it even if it's totally pointless.

tptacek 8 hours ago | parent [-]

"Have your XYZ give the LLM some JSON" is pretty close to how all tool calling works with or without MCP.

what-the-grump 7 hours ago | parent | next [-]

What next you are going to tell me rest and async are implemented in code?! And not just willed into existence by the compiler!

mycall 8 hours ago | parent | prev [-]

Markdown is for output too.