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What if you don't need MCP at all?

(mariozechner.at)
237 points jdkee | 5 comments | 16 Nov 25 18:58 UTC | HN request time: 0.442s | source
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upghost ◴[16 Nov 25 23:31 UTC] No.45949444[source]▶
So I don't disagree with any of the criticisms of MCPs but no one here has mentioned why they are useful, and I'm not sure that everyone is aware that MCP is actually just a wrapper over existing cli/API:

1. Claude Code is aware of what MCPs it has access to at all times.

2. Adding an MCP is like adding to the agent's actuators/vocabulary/tools because unlike cli tools or APIs you don't have to constantly remind it what MCPs it has available and "hey you have access to X" and "hey make an MCP for X" take the same level of effort on the part of the user.

3. This effect is _significantly_ stronger than putting info about available API/cli into CLAUDE.md.

4. You can almost trivially create an MCP that does X by asking the agent to create an MCP that does X. This saves you from having to constantly remind an agent it can do X.

NOTE: I cannot stress enough that this property of MCPs is COMPLETELY ORTHOGONAL to the nutty way they are implemented, and I am IN NO WAY defending the implementation. But currently we are talking past the primary value prop.

I would personally prefer some other method but having a way to make agents extensible is extremely useful.

EXAMPLE:

"Make a bash script that does X."

<test manually to make sure it works>

"Now make an MCP called Xtool that uses X."

<restart claude>

<claude is now aware it can do Xtool>

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1. whoknowsidont ◴[17 Nov 25 02:02 UTC] No.45950253[source]▶
>This effect is _significantly_ stronger than putting info about available API/cli into CLAUDE.md.

No it's not.

Honestly this conversation is extremely weird to me because somehow people are gravely misunderstanding what MCP even purports to do, let alone what it actually CAN do in the most ideal situation.

It is a protocol and while the merits of that protocol is certainly under active discussion it's irrelevant because you keep adding qualities about the protocol that it cannot deliver on.

Just same facts to help steer this conversation correctly, and maybe help your understanding on what is actually going:

* All LLM's/major models have function & tool calling built in.

* Your LLMs/models do not have any knowledge on MCP, nor have they been trained on it.

* MCP exists, at least the claim, is to help standardize the LIFECYCLE of the tool call.

* MCP does not augment or enhance the ability of LLM's in any form.

* MCP does not allow you to extend agents. That's an implicit feature.

* If you have access to "X" (using your example), you don't need anything that obeys the MCP standard.

MCP at best is for developers and tool developers. Your model does not need an MCP server or client or anything else MCP related to do what is already been trained to do.

>I would personally prefer some other method but having a way to make agents extensible is extremely useful.

They already are. MCP does not help with this.

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2. cjonas ◴[17 Nov 25 02:58 UTC] No.45950496[source]▶
This response is spot on. People seem very confused about what MCP actually is. It's just a standard way to provide an LLM with tools. And even how that happens is up to the agent implementation. There are some other less common features, but the core is just about providing tool definitions and handling the tool_call. Useful but basically just OpenAPI for LLM
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3. smallnamespace ◴[17 Nov 25 03:02 UTC] No.45950518[source]▶
Three facts to consider:

1. CLAUDE.md is not part of the system prompt

2. The Claude Code system prompt almost certainly gives directions about how to deal with MCP tools, and may also include the list of tools

3. Instruction adherence is higher when the instructions are placed in the system prompt

If you put these three facts together then it’s quite likely that Claude Code usage of a particular tool (in the generic sense) is higher as an MCP server than as a CLI command.

But why let this be a limitation? Make an MCP server that calls your bash commands. Claude Code will happily vibe code this for you, if you don’t switch to a coding tool that gives better direct control of your system prompt.

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4. whoknowsidont ◴[17 Nov 25 03:35 UTC] No.45950646[source]▶
>is higher as an MCP server than as a CLI command.

What do you mean by "higher"?

5. anon84873628 ◴[18 Nov 25 02:04 UTC] No.45960589[source]▶
I think people are really underappreciating the "OpenAPI for LLM" part. The hype forced a lot of different SaaS products and vendors of all stripes to actually follow a standard and think somewhat critically about the usability of what they expose.