Having a standard does make sense though, because it lets agent services handle external calls in a standard way. So, for example something like Anthropic's agent platform will proxy all MCP calls and hide the credentials so that you don't have to worry about the agent leaking secrets into code/logs/the internet. Of course you could build a similar layer to proxy traffic to various APIs, but it becomes easier to make the whole thing plug and play if everyone agrees on the shape of the API (MCP).