MCP Explained

(mcp-explained.com)

116 points | by rwilinski 2 hours ago

16 comments

  • flr03 7 minutes ago

    It's almost 2027 and I still dont understand if we actually need MCP. I must admit I am not really surfing the AI wave. But looks like a nothing burger.

    • nater5000 2 hours ago

      This is too dense. You might as well just post some Python code with sufficient comments to get the same point across. I think a nicely written article with a few diagrams would go a long way. Sometimes less is more.

      MCPs don't really need this level of technical explanations (it's basically just a REST API with standardized endpoints for discovery aimed at agents), and AI agents really do lack in the taste dimension when it comes to these things.

      • Aurornis 30 minutes ago

        > 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.

        • iugtmkbdfil834 7 minutes ago

          Sign of times man. Not that long ago -- on HN mind you -- someone posted an article that landed on main page that used lsblk as some sort of secret hacker linux command.

          • sharifhsn 25 minutes ago

            It is not technically REST, but it is basically REST. The alternative to a server endpoint is JSON-RPC over stdin which has the same request/response format as REST. This is exactly the point about over-complicating it by saying "it's not REST, it's not JSON-RPC". It's a JSON request/response protocol with a defined format.

            • parineum 18 minutes ago

              That's the purpose of the comment, to make a comparison that's simpler than the article that is missing from the article.

              If the article said, "It's basically just REST". There'd be no need to comment as such.

              • taneq 19 minutes ago

                While we’re applauding brevity, three cheers for the first line being “model context protocol”. While yes, this one is common, it’s still nice not having to scroll through 20 screens of blah to still not find out what the thing is.

              • jrmg 2 hours ago

                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.

                • bityard 42 minutes ago

                  This is a problem with most docs I encounter. _Good_ documentation should also teach the user how to use the thing, not simply end up as glorified out-of-band code comments.

                  • Geezus_42 33 minutes ago

                    I found that it's a mistake I would often make when writing documentation about something I deeply understand. I forget the questions that led me to that understanding. Now I make a conscious effort to think about the knowledge of the intended audience. I still miss things, but that's why it's good to have other people review.

                • dingaling911 1 hour ago

                  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.

                  • WhitneyLand 1 hour ago

                    In this context/application I see a lot of similarities.

                    They both provide stateless RPC methods and human readable metadata that makes them easy to route.

                    You could ask why json-rpc was even necessary for 2.0. I think mostly just for stdio and backwards compatibility.

                    • dingaling911 56 minutes ago

                      In the venn diagram of MCP and REST, there is an (optional) overlap for sure but one does not subsume the other.

                  • amelius 19 minutes ago

                    > This is too dense.

                    Maybe it was written for an AI? :)

                    Or by an AI? Or both?

                    • WhitneyLand 1 hour ago

                      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.

                    • 1ba9115454 1 hour ago

                      The best thing about MCP is its almost impossible to use for most people except developers. Therefore ensuring our existence.

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

                      • spike021 18 minutes ago

                        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.

                        • Aurornis 24 minutes ago

                          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.

                          • mmnfrdmcx 46 minutes ago

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

                            • camcil 1 hour ago

                              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.

                              • huntertwo 50 minutes ago

                                I agree - MCP just standardizes APIs to make it easier for LLM clients to consume them. Imagine if we had to use standard APIs - it would be more difficult to enable any single one. That’s why the labs instituted MCP.

                                • otabdeveloper4 23 minutes ago

                                  > MCP just standardizes APIs

                                  No it doesn't. It adds yet another Nth "API standardization" spec.

                            • padolsey 59 minutes ago

                              MCP is that kind of thing a manager comes up to you with and says "ARE WE USING MCP? it's the latest thing" and you roll your eyes, hunch over, stare at your screen and say to yourself "no, we're using strings, just strings." as you watch them drift to their next prey, you see scrawled up in their hands a note with crossed out acronyms. NFT. Web3. AMP. SOAP. IoT.

                              • ndriscoll 1 hour ago

                                Are MCP calls composable in e.g. codex yet? e.g. can a model pipe a jira MCP call to grep or sed, or at least into a file? Last I looked at MCP it was just a vastly worse version of curl, .netrc, and some short text files describing calls (which are themselves greppable). Is there anything useful beyond that that I'm missing?

                                • zzbzq 1 hour ago

                                  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.

                                  • cefboud 1 hour ago

                                    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.

                                    • kbdiaz 1 hour ago

                                      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.

                                      • dingaling911 1 hour ago

                                        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"

                                      • sputknick 2 hours ago

                                        I couldn't find a github link, if anyone knows where to find the code for this, I'd like to modify it to make it a primer more friendly to non-technical managers.

                                        • nater5000 2 hours ago

                                          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.

                                          • sputknick 2 hours ago

                                            LOL, its early, if I'd thought for 5 seconds I would have realized that. thank you.

                                          • Gshaheen 2 hours ago

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

                                          • amelius 20 minutes ago

                                            Do you really need to know how this plumbing works? I'd just tell the AI how to use a tool, and to write the MCP spec if it is really ever needed.

                                            • cityofdelusion 17 minutes ago

                                              Too dense. I’m not sure how this was outlined to the LLM but please first educate yourself on the basic principles of teaching, learning, and education. The AI that made this went off the rails and it is borderline incomprehensible.

                                              • shaolinspirit 2 hours ago

                                                mcp's are barely needed, good cli's are usually better

                                                • tedivm 1 hour ago

                                                  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.

                                                  • nicholassmith 16 minutes ago

                                                    Completely agree, MCP is going to be a continuing topic for providing capabilities to LLMs for non-technical users. If you're in a tightly regulated enterprise environment asking your IT admin to enable CompanyX's MCP Connector in Claude is much more palatable than asking for a CLI tool to be installed as well.

                                                    • mattw2121 1 hour ago

                                                      100% agree. I've been building MCPs that enable Claude (my agent of choice to have voice conversations with). These hook into my home maintenance system (https://homemaintlist.com) and workout tracking system (https://tallyup.codewalkers.net) plus several private mcp servers I've made to expose Claude to specific services. These all allow me to just have conversations with Claude and have all these very specific things available and take action on them.

                                                      • Excellent points. We still need to employ good cybersecurity principles when granting AI access to tools and resources. Let’s not throw out everything learned in the last three decades. Keep the access narrow in scope and targeted.

                                                        • shaolinspirit 1 hour ago

                                                          I do agree with you and was not aware of those reasons before, thanks for clarifying.

                                                          • toddmorey 1 hour ago

                                                            fwiw, I’ve only done cli tools for agents to install in their own sandboxes, not access on remote machines.

                                                            This was just to avoid MCP infra, but the newer stateless protocol makes that much more trivial.

                                                          • ByteOfWood 52 minutes ago

                                                            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.

                                                            • insin 13 minutes ago

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

                                                              Tool calls being composable or not are a property of the harness being used, not of MCP servers

                                                            • littlecranky67 1 hour ago

                                                              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.

                                                              • toddmorey 1 hour ago

                                                                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!

                                                                • imtringued 1 hour ago

                                                                  My suggestion is to just let the HTTP client itself be the MCP server.

                                                                  Then you don't need an MCP server per service anymore, you just need one and a whitelist of authorized services.

                                                                • mmnfrdmcx 44 minutes ago

                                                                  MCPs with oauth have a better security story

                                                                  • dominotw 2 hours ago

                                                                    not this tired discusssion again

                                                                  • not-tarnished 8 minutes ago

                                                                    AI Slop

                                                                    • enjoyyourlife 57 minutes ago

                                                                      For me it's just:

                                                                      from mcp.server.fastmcp import FastMCP

                                                                      • huntertwo 52 minutes ago

                                                                        For me it’s just

                                                                        “Claude add an mcp for this”

                                                                      • flyingsky 2 hours ago

                                                                        I've been thinking alot about developer education and while I think this format is fun to fiddle with, I feel this(and a lot of technical learning resources) are no longer as valuable as they would have been in a world without LLMS. Now if I wanna learn something I ask claude and I can essentially build my knowledge incrementally, have it build animations iteratively, ask questions and essentially derive an understanding.

                                                                        • vatsachak 54 minutes ago

                                                                          Horribly designed

                                                                          • jayd16 52 minutes ago

                                                                            Want to be more specific?

                                                                            • redwood 18 minutes ago

                                                                              Well for the step by step I cant keep up woth the looping speed and cant go back

                                                                          • jimbokun 2 hours ago

                                                                            My take away from this overview is that MCP is just a synonym for JSON RPC.

                                                                            • bibelo 2 hours ago

                                                                              AI slop sorry

                                                                              • ddellacosta 2 hours ago

                                                                                This is noisy slop that doesn't explain anything. Maybe try starting with a definition and a single diagram?

                                                                                I swear when I see stuff like this is makes me depressed about the future of our industry. Pick up an Edward Tufte book or something and use your brain

                                                                                • brazukadev 2 hours ago

                                                                                  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.

                                                                                  • drop_star 1 hour ago

                                                                                    Everyday we get a new AI slop dashboard posted here