Claude Code reportedly adds AGENTS.md fallback support
SoftwareUnverifiedUpdated:
Anthropic has reportedly added AGENTS.md fallback support to Claude Code, so projects without a CLAUDE.md can use the cross-tool instruction file instead of requiring a separate Claude-specific copy.
Shared instructions when CLAUDE.md is absent
According to the report, Claude Code engineer Thariq Shihipar announced that version 2.1.277 supports AGENTS.md. AGENTS.md is a Markdown file containing instructions for coding agents, such as expected behavior, tool preferences, and coding conventions. If CLAUDE.md is absent from a folder, Claude Code reportedly looks for and uses AGENTS.md instead.
Developers using Claude Code alongside OpenAI Codex or other non-Anthropic tools had to maintain separate CLAUDE.md and AGENTS.md instruction files, often using workarounds such as symlinks to keep them aligned.
Claude Code version 2.1.277 reportedly checks for and uses AGENTS.md when no CLAUDE.md is present. The behavior can be enabled or disabled with the /config command.
Duplicate configuration across tools
AGENTS.md is intended to work across tools, whereas CLAUDE.md can contain Claude-specific instructions. The reported fallback could reduce duplicate agent-configuration files for developers working across Claude Code, OpenAI Codex, and other tools.
Sources
- The RegisterAnthropic decides to support OpenAI's markdown instructions specRead source →