I feel MCP emerged too quickly. It will take some time and further protocol versions/enhancements for it to mature, and address stuff like security. Also it was not vetted by a conventional standards body, but just made public by a company. Lots of hype around it, everyone seems to be talking MCP these days.
This is a key point - where are the applications?
Normally we have a standard when we have applications, but I am not seeing these yet... perhaps I am blind and mad!
Three big places:
1 - Claude Desktop (and some more niche AI chat apps) - you can use MCPs to extend these chat systems today. I use a small number daily.
2 - Code Automation tools - they pretty much all have added MCP. Cursor, Claude Code, Cline, VSCode GH Codepilot, etc ...
3 - Agent/LLM automation frameworks. There are a ton of tools to build agentic apps and many support using MCP to to integrate third party APIs with limited to no boilerplate. And if there are are large libraries of every third party system you can imagine (like npm - but for APIs) then these are going to get used.
Still early days - but tons of real use, at least by the early adopter crowd. It isn't just a spec sitting on a shelf for all the many faults.
These examples seem to be tools built on this tool - which is cool and all, but it's not the equivalent of "a mail order catalogue you can access through your computer", or "a replacement for a travel agent".
What are the applications at the level of Amazon.com, Expedia, or Hacker News?
They are little things like “hey I want to get the LLM to fetch logs from elasticsearch” or “hey I want to create a way for the LLM to query my database in a more structured way”.
And yeah in theory openapi can do it but not nearly as token efficient or user efficient. OpenAPI doesn’t help actually “connect” the LLM to anything, it’s not a tool itself but a spec. To use an OpenAPI compliant server you’d still need to tell the LLM how to authenticate, what the server address is, what tool needs to be used to call out (curl?) and even then you’d still need an affordance for the LLM to even make that call to curl. That “afforance” is exactly what MCP defines. It provides a structured way for the LLM to make tool calls.