We've gone through some pain in getting MCP Servers, MCP Clients and Oauth all play well. We figured it's a pain getting people to agree that their code is broken and things would work a lot well if every did the spec right. So we built authprobe
authprobe (cli or github-action) does a quick scan by walking discovery steps to see if things are kosher and spec aligned. It helped us clean up a few things and also saw it got used in the wild to diag. mcp gaps
https://github.com/authprobe/authprobe
looking for public mcp endpoints to test and any feedback, features that could make this more useful