Anthropic hasn't done anything customer hostile to me.
I see my GPT5.x harness seek out and read CLAUDE.md files all the time.
to be clear, I don't mean that Claude refuses to read AGENTS.md files, but that Anthropic refuses to bake AGENTS.md into the harness as a first-class feature.
Claude the model by now has learned what an AGENTS file is, and itself is not petty enough to ignore it for partisan purposes, but claude-code the harness doesn't natively support it.