AGENTS.md is specifically for agents. Every time you launch an agent in a repo, it's the agent's first time existing in the universe. This file lets it orient with the project.

Humans don't need it. Nor do they need to be reminded to launch subagents for simple tasks for example - which is another command that belongs in AGENTS.md.

I find agents need a lot of verbose instructions that are a waste of space for people. Things that are better said in a PR comment for people if needed are better front loaded for agents. People benefit from concise documentation that they are thus more likely to actually read.

For example, "don't write comments that reference things that you removed from the code" is commonly needed for coding agente and almost never needed for people.