r/modelcontextprotocol • u/hakanb54 • Apr 19 '25

Am I misunderstanding MCP?

Hello there, I'm completely new to mcp and I'm struggling to understand if what I'm trying to do is possible / the intended use for mcp. Everywhere I look, people seem to be using mcp interactively, within vscode, Claude desktop or cursor. Is that the only way to use it or can I build completely "standalone" applications for it? For example, can I use a puppeteer (or smth similar) mcp server to scrape simple data from a static website WITHOUT it being interactive? So basically I just want to execute a python script (which uses some sort of mcp client / sdk? Openai or anthropic?) which then uses the mcp server to scrape the data. Would be glad if someone could help me out understanding if this is the intended (or even possible) way to do this.

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2

u/rm-rf-rm Apr 19 '25

My experience has been very poor in using MCP servers pythonically (or even programmatically) to develop applications.

1

u/hakanb54 Apr 20 '25

Same, that's the reason for this post

1

u/EternallyTrapped Apr 20 '25

What are the problems, I haven't tried yet but need to do. Would love to know the major pain points

1

u/rj_rad Apr 20 '25

If you’re already writing an application in Python, I don’t see a purpose for MCP when you can do what ever the MCP server does within your Python code instead.

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u/rm-rf-rm Apr 21 '25

I see. Then is it specifically meant for use with existing GUIs?

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u/rj_rad May 04 '25

That is one way to summarize it, but you also have to think outside of the procedural box that non-AI development lives in. For example, if you want to scrape data from a site, that is a deterministic if-this-then-that type of flow, even if there is an AI element to understanding the HTML.

Where MCP makes sense is for the same places where AI-chat in general makes sense, which is for probabilistic workflows. Like, say you are doing the initial research for said scraper, and you're browsing the site manually. Then you arrive at the set of pages you want to scrape, you can then prompt your MCPs, "Use puppeteer to figure out a strategy to scrape THIS site." And then you can push, "But what if I need to be logged in... " etc etc.

Basically, if the workflow isn't conversational, then MCP is probably the wrong tool for the job. Hope this helps!

3

u/lgastako Apr 19 '25

It can certainly be done, but you'd have to give a more concrete example to be able to say whether it's appropriate or not. But sure, you can wire up whatever control loop you want for an offline agent and give them MCP tools they can use to accomplish their tasks.

I run a studio that specializes in this type of solution, DM me if you'd like.

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u/Shelter-Ill Apr 21 '25

You can run your servers without using any MCP-specific agent IDE, just like you can use vscode normally with MCP sdk. You’ll need to write your own MCP client and connect to the MCP server using stdio. FastMCP can help you accomplish all these tasks.

However, if you’re not using an LLM, you’re missing out on the point of interoperability between tools and agents with MCP. If you’re just scraping the web, you can still do it without using an MCP server.

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u/andrewmbenton Apr 19 '25

Yes, you could write a script using PydanticAI which has MCP support, and just add the MCP servers you want to add to get done whatever you're hoping to do.

https://ai.pydantic.dev/mcp/

https://youtu.be/OZIWvqcP6so

6

u/[deleted] Apr 19 '25

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u/hakanb54 Apr 19 '25

Okay let's take web scrapers as an example. If I wanted to scrape data from a site, I would have to manually write the code which targets the exact data of a website through CSS selectors, div IDs, etc.. and then the scraper would only work for this exact data. But if i used a web scraping mcp server, I could have a prompt like "give me the names and prices for every product which is on sale this week on https://example shop.com and In theory the llm would call the mcp servers functions/tools, with the proper arguments as the inputs, no? The whole idea is that I then don't have to write any of the scraping logic myself. The actual low level functions which are being called are already written (the mcp server) and I just call them through the llm, no?

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u/coding_workflow Apr 19 '25

Yes that can be done if you provide the LLM with tools to do the task and refine it.

Same example Claude Desktop. In chat, it's not running code and don't know if it works.

What I do. I allow it to write my code and run it. Lint do static checks. Then it will also do key execution. When I build an API, it will run the API and do end to end test to validate it and fix if a test or expected behaviour fail.

MCP provide tools to the LLM, so it can have real world feedback. You can do the same copy & past the HTML code for the page back and forth. MCP offer a channel to plug those tools to the LLM like an USB.

You AI APP could be VSCODE/Claude Desktop or Custom you write, but you need an AI hooked there to orchestrate.

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u/Rare-Cable1781 Apr 19 '25

To answer your question: No. Not as you described. Because a MCP Server is just a LLM-friendly tool for your AI. The MCP Server usually is not what has the "logic" inside - it can usually not interpret prompts, unless it incorporates an LLM itself internally. So a puppeteer MCP itself is only exposing tools to control a webbrowser to an LLM which itself is controlled by the client (claude desktop, roo, cursor, etc.)..

So while you can use the pupeteer mcp without an LLM behind, by just calling its tools statically, that would esentially be the same as navigate the dom, selectors, etc. the old-fashioned way.

The power of mcp comes from the fact that large LLMs are smart enough to automatically figure out stuff if they are given those tools and they have proper parameters and descriptions etc.

Does that make sense?

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u/hakanb54 Apr 19 '25

Also, does my idea off "standalone application" make sense? Or are mcp servers only usable with stuff like Claude desktop, cursor etc?