AGENTS.md is the file every coding agent reads.
Codex, Cursor, GitHub Copilot, Gemini CLI, Jules, Windsurf, Aider, Zed, Warp, RooCode, Amp, Factory… and Claude Code, with a one-line shim. The open standard, in working form.
AGENTS.md is the open standard - mid-2025 collaboration between OpenAI, Sourcegraph, Google, Cursor, Amp, Factory, now stewarded by the Linux Foundation. 60,000+ open-source projects ship one.
CLAUDE.md is Claude Code's proprietary equivalent. As of April 2026, Claude Code does not natively read AGENTS.md, despite a 3,000+ upvote feature request open since August 2025.
The fix is one line. Your CLAUDE.md contains @AGENTS.md. Single source of truth. When Anthropic eventually ships native support, you delete the stub.
# What you get your-project/ +-- AGENTS.md canonical agent instructions +-- CLAUDE.md one line: @AGENTS.md (Claude Code shim) +-- AGENTS.override.md.example personal overrides template (gitignored) +-- .gitignore ignores .override.md +-- examples/ | +-- frontend/AGENTS.md subpackage scoping | +-- backend/AGENTS.md | +-- tests/AGENTS.md +-- .agents/ | +-- skills/run-tests/SKILL.md open-spec skill example +-- docs/ +-- COMPATIBILITY.md which agent reads what +-- HIERARCHY.md precedence rules + worked examples
Most major coding agents read AGENTS.md natively. One holdout (which you can shim).
# Native AGENTS.md support, April 2026 Codex - the canonical implementation Cursor - AGENTS.md or .cursorrules GitHub Copilot - agents enabled Gemini CLI - Google's CLI agent Jules - Google async coding agent Windsurf - IDE agent Aider - terminal pair-programmer Zed - editor with AGENTS.md Warp - terminal agent RooCode - VS Code extension Amp - Sourcegraph Factory - agentic coding platform # The lone holdout Claude Code - reads CLAUDE.md only (use the @AGENTS.md shim)
The community noticed. The GitHub feature request asking Anthropic to support AGENTS.md has 3,000+ upvotes and zero official response since August 2025. The duplicates filed since then have all been auto-closed by bots.
Most projects don't ship an AGENTS.md at all. The few that do, ship a flat 80-line dump that covers everything and prioritizes nothing. Frontier models reliably follow ~150-200 instructions before quality degrades; the agent's system prompt already eats ~50.
The kit is the working version of the open spec. A fillable canonical template, three subpackage examples, an override pattern that's first-class in Codex, a skill in the open .agents/skills/ format, and the one-line CLAUDE.md shim that gets you Claude Code compatibility today.
Sister kit for the deep .claude/ system (skills, rules, hooks, custom commands, agents): claudemd.kurkalabs.dev. Use both if you ship to Claude Code primarily; this one alone if you ship cross-agent.
The kit ships a one-line CLAUDE.md stub: @AGENTS.md. That single import gets your Claude Code session reading the same canonical file every other agent already does. Single source of truth. When Anthropic ships native AGENTS.md support, you delete the stub.
If you want the deep Claude Code system on top - skills, rules, hooks, custom commands, agents, .claude/ subsystems - install the claudemd-kit alongside this one. They compose.