Anthropic on Friday said it is adding support for OpenAI's AGENTS.md specification to Claude Code, according to Claude Code engineer Thariq Shihipar. Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md, and users can toggle this behavior with the /config command. Until now, developers using Claude Code alongside OpenAI Codex or other non-Anthropic tools had to maintain two sets of Markdown instructions, CLAUDE.md and AGENTS.md, plus project-specific versions, because the formats are similar but not identical, with CLAUDE.md possibly containing Claude-specific instructions while AGENTS.md is intended to be tool agnostic. Workarounds included symlinks to keep the files in sync. Last year, OpenAI contributed AGENTS.md to the Agentic AI Foundation under the Linux Foundation, and as of December 2025, more than 60,000 open source projects implemented AGENTS.md. Many widely followed software developers applauded the decision, and OpenAI's head of core product, Thibault Sottiaux, remarked, "Yay! This is the way. Come to the light," to which Shihipar responded with the handshake emoji.