Claude Code adds support for AGENTS.md starting with version 2.1.277. In a post on X, @trq212 says Claude Code will check for and use an AGENTS.md file when the relevant folder does not contain a CLAUDE.md file.

The announcement also says the behavior can be toggled from Claude Code’s /config command. It doesn't give the setting’s name or step-by-step instructions.

When Claude Code checks for AGENTS.md

The condition described in the announcement is specific: Claude Code checks for AGENTS.md if there is no CLAUDE.md in the folder.

That means the announcement establishes a fallback condition, not that the two files are combined or that AGENTS.md replaces CLAUDE.md. It also does not explain what happens when both files are present.

Version requirement

The support begins with Claude Code version 2.1.277, according to the announcement. The post doesn't mention support in earlier versions.

Still unclear

Anthropic hasn't said:

  • What format or syntax AGENTS.md should contain

  • What happens when a folder contains both CLAUDE.md and AGENTS.md

  • The exact /config setting or the steps needed to change it

Sources