Claude Code will now follow the instruction file its rivals use.
Anthropic's coding tool now reads AGENTS.md, the rules file rival agents already share, when no CLAUDE.md exists. The change shipped on Thursday in Claude Code version 2.1.277. The cloud versions of the tool do not have it yet.
Why it mattersEvery agent wanting its own rules file made switching coding tools costly. One shared file means the instructions you write today survive your next tool.