Claude Code now reads AGENTS.md if there is no Claude.md

Claude Code's changelog confirms that, starting in version 2.1.277, the tool reads a project's AGENTS.md file as a fallback whenever no CLAUDE.md is present. AGENTS.md is a convention other coding agents already read for repo-specific instructions, so a repository that only maintains one instructions file no longer needs a Claude-specific duplicate to get Claude Code to follow it. Simon Willison's write-up, citing Anthropic's Thariq Shihipar, describes the change as one of the first built-in 'Claude Code mods,' with a customization system for building further mods described as coming soon. For teams running more than one coding agent against the same repository, the practical effect is one less file to keep in sync: a project can standardize on AGENTS.md as the shared instruction file and let CLAUDE.md stay reserved for genuinely Claude-specific guidance, or drop it entirely. The mods framing is worth watching too, since it signals Anthropic building an extension point into Claude Code's own behavior rather than only into the models it calls.