Claude Code release notes: 2.1.277 reads AGENTS.md

Claude Code 2.1.277 can read a project's AGENTS.md directly. This Markdown file holds instructions for coding agents, such as how to build and test the project. A repository that already uses it therefore does not always need a separate CLAUDE.md for Claude.

The release was published on September 18. When checked on September 21, 2.1.278 was the latest version on both GitHub and npm; AGENTS.md support arrived in 2.1.277.

Sources: Claude Code 2.1.277 release notes. Claude Code 2.1.278. npm registry.

How Claude Code chooses instruction files

By default, Claude reads AGENTS.md when the working directory and its parent directories contain no CLAUDE.md, .claude/CLAUDE.md, or CLAUDE.local.md. If any of these exist, Claude reads them instead. Your personal instructions in ~/.claude/CLAUDE.md and your organization's managed instructions do not block loading.

Human step: Type /config in Claude Code and open Project instructions. Choose claude-md-and-agents-md to load both file types. The change applies from your next message and in new sessions. You do not need to rename existing files.

Automatic loading shows an AGENTS.md loaded line in the interactive session. However, a directly loaded file does not appear in /memory or under Memory files in /context.

Source: Claude Code: AGENTS.md and project instruction settings.

Availability and existing imports

Direct support requires version 2.1.277 or later and a session that fetches feature flags from Anthropic. It is not yet available on Bedrock, Vertex, or Foundry, or in sessions with telemetry disabled. The first session after installation or an upgrade also lacks support; it starts working from the next session.

Support is also unavailable if disableAllHooks or allowManagedHooksOnly is enabled, or if the built-in agents-md plugin has been disabled.

Human step: Where direct support is unavailable, put the line @AGENTS.md in a CLAUDE.md beside the file. An existing import can stay even where direct support works: Claude does not read the file twice.

Source: Claude Code: limitations and imports from CLAUDE.md.