> somebody, somewhere, was taking advantage of that to give one set of instructions to Claude, and a different set of instructions to some other provider.

I'm this person, I am actively doing this! I have some instructions which the Claude models need and OpenAI models will do by themselves. If the OpenAI models see the Claude instructions, they will go way overboard in a way I don't want.

Mind, the change does not affect me at all, because when both instructions are present Claude continues to read CLAUDE.md and Codex continues to read AGENTS.md. But if Claude started preferring AGENTS.md, that would be mildly annoying.

▲ californical 24 minutes ago | parent [-]

Within agents.md, an idea. Feel free to steal if you work on this:

    Model.Claude*:
      Do this one thing

    Model.Claude.Opus.4.8:
      Extra specific instructions

    Model.*:
      This is relevant to everyone

    Harness.ClaudeCode*:
      Why not, let’s allow harness specific instructions so you can do things differently depending how you’re working

	▲	dotancohen 8 minutes ago \| parent [-]
		I would like to subscribe to your newsletter. Seriously, though, this is a great idea. Good communicators know to tailor their discourse to their audience. LLMs are just as sensitive to small variations in prompts, and just as inconsistent between them, as are humans.