September 18, 2026
AGENTS.md becomes a shared instruction file for agents: Claude Code reads it from version 2.1.277
On September 18, 2026, [Claude Code](/tools/claude-code) added AGENTS.md support in version 2.1.277. If a folder has no CLAUDE.md, the agent reads AGENTS.md. The toggle is under /config → Project instructions, but the feature is not yet available on Bedrock, Vertex, or Foundry.
Romain Huet
@romainhuet
Claude Code 🤝 AGENTS.md Great to see the ecosystem converging on one shared standard. Congratulations to the team!
We're adding support for AGENTS.md to Claude Code. Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md. You can toggle this behavior in /config.
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Previously, Claude Code required CLAUDE.md for instructions. Now AGENTS.md brings together rules for Codex, Amp, Cursor, and Claude Code when a project has no CLAUDE.md of its own. Nested AGENTS.md files apply within their respective folders. To load both files at once, set instructionFiles: "claude-md-and-agents-md" in ~/.claude/settings.json.
The source code for the built-in agents-md module has been published in the Claude Code repository.
