:(
What does the file change for an agent that already reads the tree? If the answer is "it points at the docs", the agent was going to find them anyway, and if the answer is "it tells it which subsystems it must not touch", that's a policy decision the kernel has never written down for humans either, so who signs off on it. What happens when AGENTS.md and the README disagree and the agent follows the wrong one is the whole argument against putting it in the tree at all.
