Keeping two instruction files in step for one repository was the tax teams paid for running more than one coding agent. Anthropic has retired part of it: Claude Code now reads AGENTS.md, the convention Codex and most rivals adopted.
Previously the tool looked only for CLAUDE.md. Under version 2.1.277, a folder without CLAUDE.md leads Claude to check AGENTS.md instead, technical staff member Thariq Shihipar said. The format is shepherded by the Agentic AI Foundation, an initiative housed at the Linux Foundation.
Maintenance was the pain point. Amit Kumar Jena, who leads AI development at the consultancy Kanerika, said teams either synchronized the two files by hand or worked around it with a symlink or a single import line. Those tricks hold in a small project, he said, but unravel in a monorepo where instructions sit at several directory levels, letting the files drift until deadline pressure hides the damage. Charlie Dai of Forrester framed a common format as a control point for conventions, security requirements and architectural limits.
Two caveats apply. Claude-specific features live in CLAUDE.md with no AGENTS.md equivalent, so identical instructions may behave differently across agents. Support also hinges on the tool retrieving feature flags from Anthropic, which leaves Bedrock, Vertex AI and telemetry-free installs on CLAUDE.md. Teams can override the order through configuration.
