It was a vibe protocol and with the hindsight glasses on it is obvious.
Someone should have said to the llm coming up with it -- "that sounds like an API with extra steps ... how about we keep these things (tool descriptions) and get rid of all this irrelevant - this will look good in my promotion meeting - overengineering (everything else)"
You are absolutely right is what it would have replied with.
OpenAPI already exists, you can serve it on an endpoint for tool descriptions. Why did we need MCP again?
that would be tokens, vibes and guesses all the way down
As is the entirety of using an LLM? If you want something deterministic and efficient you get the agent to write a script, verify it, then run it yourself.
Bring back FastCGI, enable the setting in Apache to list a directory, and point the agent to your cgi-bin directory full of all your tools. Calling the bin without any input provides the help text or the interface to the tool.
You can probably throw together a passible auth system on top of it that works with the htaccess format. Which is another cgi script but chowned so it can't be called from the outside. If not that, public key crypto - give your agents certificates that are part of the chain of trust. Mint those out of band and give them an insanely short TTL. Fail2ban or something like that to prevent abuse (agent getting handsy with the server gets blocked, credentials revoked).
The side benefit is that everybody starts writing perl and awk again. Who needs a JS runtime when you have CGI?
What hindsight, this was obvious from day one.