A lot of the reasons to use MCP are contained in the architecture document (https://modelcontextprotocol.io/specification/2025-11-25/arc...) and others. Among them, chief is security, but then there's standardization of AI-specific features, and all the features you need in a distributed system with asynchronous tasks and parallel operation. There is a lot of stuff that has nothing to do with calling tools.
For any sufficiently complex set of AI tasks, you will eventually need to invent MCP. The article posted here talks about those cases and reasons. However, there are cases when you should not use MCP, and the article points those out too.
> Among them, chief is security
The security is so chief that they had no security at all until several versions later when they hastily bolted on OAuth.
MCP is a vibe-codef protocol that rode one of the many AI hype waves where all "design documents" are post-hoc justifications.
>Among them, chief is security
Considering many popular MCPs have done auth incorrectly, this made me lol
If the chief reason to use MCP is security, I'm sold: it's a dead letter, and we're not going to be using it a couple years from now.