Claude Code now reads AGENTS.md if there is no Claude.md

Claude Code's release notes page, generated from the CHANGELOG.md on GitHub, lists the changes across a long run of versions (from 0.2.x and 1.0.x through the 2.0.x and 2.1.x lines). The dated entry for September 18, 2026 is the substantive new item: Claude Code now supports AGENTS.md. In a project with no CLAUDE.md present, the tool will read AGENTS.md instead as its source of project instructions, and this preference can be changed under "Project instructions" in the /config interface.

The same entry notes the feature is not yet available on Bedrock, Vertex, or Foundry, so it currently applies only to the standard Claude Code distribution. A second addition in that release introduces an environment variable beginning with CLAUDE_GATEWAY_PROXY_IS_EGRES (the changelog text is truncated at that point in the excerpt).

Why it matters: AGENTS.md has become a de facto shared convention across coding agents, so falling back to it lets Claude Code reuse instruction files already maintained for other tools rather than requiring a Claude-specific CLAUDE.md. The practical caveats are that CLAUDE.md still takes precedence when both exist, users can override the setting via /config, and enterprise deployments on Bedrock, Vertex, and Foundry do not yet get the behavior. As always, the installed version can be checked with claude --version.