When building agent integration for my serverless backend https://saasufy.com/, I decided to not use MCP but to put curl commands inside skill markdown files instead: https://github.com/Saasufy/skills

The curl command is extremely popular so models seem to be really good at using it.

Also I like that curl uses a bash syntax and my platform requires JSON payloads; it makes the separation clear to the agent. I find it to be very reliable.