For me, I have a service that has multiple vectors of what would be called an API - PowerShell Modules, WMI, RESTFUL Web Services, some are available, some can do some things, some are more direct, some are not allowed with enterprise security etc.

Either way, I don't do what you suggest. I have self-learning rules and have the models build a well-rounded API engine once, then re-use it with query scripts through skills. Its portable and flexible in many environments.

Did you know that computer programs, once written, can be stored to disk once and run many times?

This is my favorite position, the advantage of an MCP tends to lie more in token optimization.

> re-implement its own API client each time

Is using curl considered re-implementing your own api client each time?