[newtwilly]

It's pretty easy if you just use the MCP Python library. You just put an annotation on a function and there's your tool. I was able to do it and it works great without me knowing anything about MCP. Maybe it's a different story if you actually need to know the protocol and implement more for yourself

[neoden]

Yes, I am using their Python SDK. But you can't just add MCP to your existing API server if it's not ready to async Python. Probably, you would need to deploy it as a separate server and make server-to-server to your API. Making authentication work with your corporate IAM provider is a path of trial and error — not all MCP hosts implement it the same way so you need to compare behaviours of multiple apps to decide if it's your setup that fails or bugs in VS Code or something like that. I haven't even started to think about the ability of a server to message back to the client to communicate with LLM, AFAIK modern clients don't support such a scenario yet, at least don't support it well.

So yes, adding a tool is trivial, adding an MCP server to your existing application might require some non-trivial work of probably unnecessary complexity.