Summary & Key Takeaways ​

• Claude Code version 2.1.277 now checks for and uses AGENTS.md if CLAUDE.md is not present.
• This feature is built on Claude Code's upcoming "mods" system for customizing the agent harness.
• AGENTS.md allows developers to provide project instructions for AI agents.
• Users will eventually be able to build custom versions of project instructions themselves.
• The source for the built-in mod is available for reference.

Our Commentary ​

This is a pretty interesting move from Anthropic. Giving developers more control over how their AI agents interpret instructions via AGENTS.md and the "mods" system is a clear step towards more powerful and customizable AI workflows. I'm always looking for ways to make agents less opaque, and this feels like a good direction.