Claude Code Adds Support for the Universal AGENTS.md Instruction Standard
Anthropic engineer Thariq Shihipar announced that Claude Code version 2.1.277 now supports AGENTS.md. If a project folder lacks a CLAUDE.md file, Claude Code will automatically read and apply the rules defined in AGENTS.md. Adopting AGENTS.md promotes cross-tool interoperability, allowing developers to maintain a single shared configuration file for different AI coding assistants. This eliminates the need to rewrite project rules when switching tools or contributing to open-source projects. While CLAUDE.md remains specific to Claude Code workflows, MCP servers, and sub-agent commands, AGENTS.md acts as a universal rulebook for all AI agents. Users can toggle or configure this fallback behavior directly via the /config command.
## BACKGROUND
AI coding assistants use project instruction files to learn code structure, formatting styles, and build commands for specific repositories. Anthropic previously relied on its proprietary CLAUDE.md format, whereas AGENTS.md has emerged as an open standard designed to serve as a README specifically tailored for AI agents.