Codex, Amp, Cursor, and others are starting to standardize around AGENTS.md (https://agents.md/) — a unified Markdown file that coding agents can use to understand a codebase.

By contrast, CLAUDE.md feels too specific to Claude Code. It doesn’t work as well when collaborating with other developers who aren’t using Claude Code.