MCP Explained (mcp-explained.com)

Yeah, this feels like one of those ‘explainers’ that feel like they are great to someone who already knows how the system works, but don’t actually work for newbies because they tacitly assume knowledge of the shape of the system that seems ‘obvious’ to someone steeped in it.

It's literally JSON-RPC I'm not sure why you say it's a REST API. It's not even close to a REST API.

To me the writing itself seems pretty economical.

From your comment, I expected to be annoyed by a bunch of slop or obscurities.

My guess is the writing did not come straight out of an LLM and was carefully curated.

If I’m wrong I’d love to have the style prompt.

> it's basically just a REST API

The opening has 1 paragraph and 5 table entries. One of them is “Not REST”

It’s a little scary that this was considered too dense or complex because the basics were explained in something that could be read in 1 minute. That still wasn’t enough to stop the top HN comment (as I write this) from calling it too dense and giving incorrect information that is immediately refuted by skimming the top part of the article.

> This is too dense.

Maybe it was written for an AI? :)

Or by an AI? Or both?

Last I checked it still doesn't. A skill that tells your client to call a CLI, and uses the help menus for progressive disclosure, benchmarks better. Developers noticed this immediately and there is sort of an anti-MCP sentiment. The protocol was probably largely conceived for non-coding agents run by non-coders.

In theory the agents could just natively know how to do this better, to get exactly the composability you want. In fact, you could probably just write a CLI mcp-caller and tell the agent to only call MCPs via that, and boom you're done.

Where MCP does come back into the picture even for coders is a more controlled way to break a sandbox.

What I will also say is it matters less and less. It's the usual bitter lesson. The models are just getting so much better all attempts to optimize everything are a drop in the bucket.

Yes, they are. Look into CodeMode (available in both Opencode and Pi). The agent has access to a code execution tool that can call and compose other tools/MCPs by writing code.

Yeah, the new Pi harness has codemode and I imagine there's many more.

Internally at my startup, I built an interpreter for a subset of Javascript where the agent can compose its tools and MCPs. The cool thing about it is that it can create durable workflows and automations from these same scripts.

pi harness composes them just fine if you're specific about what you want to do.

"Find the latest prod JIRAs and analyze the related logs"

it's a single page html file, just download it and use as input for what you want to do

Literally just give the link to Claude/GPT/etc. and it'll be able to replicate it easily. Hell, just loosely describe this as a text prompt and they'll probably nail it one shot. This is basically the "default" interactive explainer one-pager that all of these models generate.

MCP honestly seems like something thrown in there to keep devs relevant.

Just like us to take something and limit it back to being useless until we implement the feature (tools).

The real "race to market" winners will just throw the credentials into the SQL connector and let 'er rip like a real man.

it's becoming pretty mainstream, lots of (ordinary, non-dev) people connecting google docs/slides, notion, linear etc to their claude or cowork

The lightly technical people I talk to have no problems getting it done.

Their secret, which is not very secret, is to ask the AI to help them set it up.

I think this might follow that bell curve meme where people on the unsophisticated and highly sophisticated ends of the curve are leveraging the LLM for MCP setup (and other routine tasks) while some in the middle are making it more complicated than it needs to be because they still think of it as outside the domain of AI-assisted work.

The biggest problem I see isn’t getting MCP set up, it’s people getting stuck using the wrong tools for the job. I’ve improved a lot of workflows by observing what someone is doing and suggesting a better tool for the job.

Multiple non-developer colleagues at my workplace are trying out all kinds of MCP connectors in their Claude instances. Maybe when MCP was mostly relegated to coding harnesses it was more of a developer's tool but things have changed a lot.

Also, Apple just announced their preview for new Siri AI capabilities and part of that is they seemingly are going to add MCP to apps (if developers of the apps want to) as tools, which would enable Siri to use functions of apps, similarly to Claude Desktop using functions of services through MCP tool calls.

You might be right. I created a quick and dirty MCP server to expose my existing REST API calls. It doesn't work as well as I hoped. The AI client seems to have trouble determining the mix of MCP tools needed to fulfill a user's prompt, unless a specific tool is defined for that request. Maybe I am missing something.

> Don't believe me? Try connecting Blender to Codex.

Is it that bad? I have Blender connected to Claude (and my mind is quite blown by how great it is to use) and it was quite easy if you could follow the tutorial (the hardest part was reading that you have to click on something twice)

I feel like I'm living in a different world than other people with my MCP experiences.

At my job we maintain an MCP for our admin portal/prod data and it's seen a lot of use. Our admin side was a mess to use so allowing admins to ask questions about prod data has been a huge help for everyone.

And for myself personally, connecting MCPs to Claude has also been an insanely huge productivity boost. It's really nice to just ask for a link to Datadog when I want to monitor some change I made, instead of trying to craft a query myself.

The manager is asking because marketing and sales are asking. They want to put a bullet-point on the feature list of the brochure. The best play is to build a compliance feature that's firewalled into a corner where it can't hurt anything. The product technically includes MCP, NFT, et al.

not this tired discusssion again

For coding agents I agree with you, but people are building for more than just developers now. The idea that a user facing service would give their agents shell access is kind of horrifying, as you then make it possible for prompt injection to mean a system take over.

MCP has its place. It should not be the default for many use cases, but if you need to expose specific tools in a secure way to agents that are not trusted to run shell commands then MCP is great. Developers need to think beyond their own use cases and consider architecture patterns if they're going to build, not just consume, AI systems.

It just removes the need to install a cli tool on your local machine. I in general are sceptical before I install some external 3rd party software. With MCP over HTTP transport, the MCP might still talk to your agent and tell the agent to do XYZ, but your agent can still treat that command as malicious and refuse to execute. While not perfect, it is just another layer of security.

It is the same with a wepapp: You could argue you don't neex browser apps if the user just install a software on their computer, but we feel better using the sandboxing environment of your browser.

Depending on use case, would start with just solid HTTP APIs, then a simple CLI to consume them, then add MCP using the new spec. Build slowly only adding new access protocols as needed.

Be surprised how far apps can get with just solid & well documented APIs. Modern agents are smart!

I agree. MCPs have the massive problem of not being composable, which is a big strength of shells/CLIs allow.

People make the argument that it doesn't matter for non-programmers. I use Bluebeam (a pdf editor which is standard in the construction industry) daily, and it has an MCP, but a big problem is that if the agent wants to import or export a large amount of data from a document, then it has to regurgitate a bunch of tokens into or out of the MCP. If it were a CLI, then it would just pipe things in and out as it needs.

I ended up just having the agent make a script that wraps the MCP so it can use it as a CLI instead.

MCPs with oauth have a better security story

I find it depends a lot on the model used and what the MCP does. I have agents trawl research papers, and just giving the raw API to DeepSeek leads to lots of wasted tokens and bad use of the API options. Here, wrapping the API to minimize the available options and providing sane defaults fixes that. Perhaps a frontier model can use the API directly without issues, but for DeepSeek a good MCP wrapper is very useful. Besides that, having control and limits in the MCP is very useful for some ratelimited APIs

Yep. This is what we get when people that didn't study UX and product development have access to AI. They have good ideas, ask AI to generate it and can't see that the result is unbearable.

Everyday we get a new AI slop dashboard posted here

Want to be more specific?

For me it’s just

“Claude add an mcp for this”