> that any agent worth its Salt should read before touching a codebase and warn the user that their contributions might not be accepted

Are you talking about some agent that is specific for writing FOSS code or something? Otherwise I don't see why we'd want all agents to act like this.

As always, it's the responsibility of the contributor to understand both the code base and contributing process, before they attempt to contribute. If they don't, then you might receive push-back, or have your contribution deleted, and that's pretty much expected, as you're essentially spamming if you don't understand what you're trying to "help".

That someone understands this before contributing, is part of understanding how FOSS works when it's about collaborating on projects. Some projects have very strict guidelines, others very lax, and it's up to you to figure out what exactly they expect from contributors.