{
  "schemaVersion": 1,
  "license": "CC-BY-4.0",
  "licenseUrl": "https://creativecommons.org/licenses/by/4.0/",
  "attribution": "Rulefiles contributors",
  "lastReviewed": "2026-10-16",
  "tools": [
    {
      "id": "cursor",
      "name": "Cursor",
      "docsUrl": "https://cursor.com/docs/rules"
    },
    {
      "id": "claude-code",
      "name": "Claude Code",
      "docsUrl": "https://code.claude.com/docs/en/memory"
    },
    {
      "id": "codex",
      "name": "Codex",
      "docsUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md"
    },
    {
      "id": "github-copilot",
      "name": "GitHub Copilot",
      "docsUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "scope": "Repository custom instructions on GitHub.com (cloud agent, code review)"
    }
  ],
  "files": [
    {
      "id": "agents-md",
      "path": "AGENTS.md",
      "description": "Open format for agent instructions. May sit in the repository root or in subdirectories."
    },
    {
      "id": "agents-override-md",
      "path": "AGENTS.override.md",
      "description": "Override file used by Codex in place of AGENTS.md in the same directory."
    },
    {
      "id": "claude-md",
      "path": "CLAUDE.md",
      "description": "Claude Code project instructions file."
    },
    {
      "id": "gemini-md",
      "path": "GEMINI.md",
      "description": "Gemini CLI instructions file."
    },
    {
      "id": "cursorrules",
      "path": ".cursorrules",
      "description": "Single-file rules format used by early Cursor versions."
    },
    {
      "id": "cursor-rules-mdc",
      "path": ".cursor/rules/*.mdc",
      "description": "Cursor project rules with frontmatter (description, globs, alwaysApply)."
    },
    {
      "id": "claude-rules",
      "path": ".claude/rules/*.md",
      "description": "Claude Code topic and path-scoped rules."
    },
    {
      "id": "copilot-instructions-md",
      "path": ".github/copilot-instructions.md",
      "description": "Repository-wide GitHub Copilot instructions."
    },
    {
      "id": "copilot-path-instructions",
      "path": ".github/instructions/*.instructions.md",
      "description": "Path-specific GitHub Copilot instructions with an applyTo glob."
    }
  ],
  "cells": [
    {
      "tool": "cursor",
      "file": "agents-md",
      "status": "reads",
      "note": "The page documents AGENTS.md in the project root and in subdirectories; nested files are combined, with more specific instructions taking precedence.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "cursor",
      "file": "agents-override-md",
      "status": "unverified",
      "note": "Not mentioned on cursor.com/docs/rules or on cursor.com/help/customization/rules when checked.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "claude-md",
      "status": "reads",
      "note": "The help page says: \"Cursor reads `CLAUDE.md` files the same way it reads `AGENTS.md`.\" It names the project root and says these files are always applied, whatever alwaysApply says.",
      "sourceUrl": "https://cursor.com/help/customization/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "gemini-md",
      "status": "unverified",
      "note": "Not mentioned on cursor.com/docs/rules or on cursor.com/help/customization/rules when checked.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "cursorrules",
      "status": "migration-only",
      "note": "The help page mentions the file only in a migration section, where it calls it \"legacy and will be deprecated\". It does not say whether Cursor still loads it.",
      "sourceUrl": "https://cursor.com/help/customization/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "cursor-rules-mdc",
      "status": "reads",
      "note": "Project rules live in .cursor/rules as .mdc files. A plain .md file in that folder is ignored.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "cursor",
      "file": "claude-rules",
      "status": "unverified",
      "note": "Not mentioned on cursor.com/docs/rules or on cursor.com/help/customization/rules when checked.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "copilot-instructions-md",
      "status": "unverified",
      "note": "Not mentioned on cursor.com/docs/rules or on cursor.com/help/customization/rules when checked.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "cursor",
      "file": "copilot-path-instructions",
      "status": "unverified",
      "note": "Not mentioned on cursor.com/docs/rules or on cursor.com/help/customization/rules when checked.",
      "sourceUrl": "https://cursor.com/docs/rules",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "claude-code",
      "file": "agents-md",
      "status": "reads-conditionally",
      "note": "Reads AGENTS.md only when there is no CLAUDE.md or CLAUDE.local.md in the working directory or above. Reading AGENTS.md directly needs v2.1.277 or later.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15",
      "version": "2.1.277"
    },
    {
      "tool": "claude-code",
      "file": "agents-override-md",
      "status": "not-read",
      "note": "The page lists AGENTS.local.md, AGENTS.override.md and anything under a .agents/ directory as not read.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "claude-md",
      "status": "reads",
      "note": "Reads ./CLAUDE.md or ./.claude/CLAUDE.md, plus user, managed and local (CLAUDE.local.md) scopes.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "gemini-md",
      "status": "unverified",
      "note": "Not mentioned on the cited page when checked, including its /init migration list.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "claude-code",
      "file": "cursorrules",
      "status": "migration-only",
      "note": "Mentioned only in the /init migration section. /init reads Cursor rules in .cursor/rules/ or .cursorrules and incorporates the relevant parts into the generated CLAUDE.md. The page does not say Claude Code loads the file itself.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "cursor-rules-mdc",
      "status": "migration-only",
      "note": "Mentioned only in the /init migration section, as Cursor rules in .cursor/rules/. /init incorporates the relevant parts into the generated CLAUDE.md. The page does not say Claude Code loads these files itself.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "claude-rules",
      "status": "reads",
      "note": "The page documents .claude/rules/ for topic-specific and path-scoped rules.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "copilot-instructions-md",
      "status": "migration-only",
      "note": "Mentioned only in the /init migration section. /init reads Copilot rules in .github/copilot-instructions.md and incorporates the relevant parts into the generated CLAUDE.md. The page does not say Claude Code loads the file itself.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "claude-code",
      "file": "copilot-path-instructions",
      "status": "unverified",
      "note": "Not mentioned on the cited page when checked, including its /init migration list.",
      "sourceUrl": "https://code.claude.com/docs/en/memory",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "codex",
      "file": "agents-md",
      "status": "reads",
      "note": "Reads AGENTS.md from the global Codex home and from the project root down to the working directory, at most one file per directory, up to 32 KiB combined by default.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "codex",
      "file": "agents-override-md",
      "status": "reads",
      "note": "Checked before AGENTS.md in each directory. In the Codex home, AGENTS.override.md replaces AGENTS.md when it exists.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "codex",
      "file": "claude-md",
      "status": "configurable",
      "note": "Not part of default discovery. The page says Codex also reads names listed in project_doc_fallback_filenames and ignores names not on that list.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "codex",
      "file": "gemini-md",
      "status": "configurable",
      "note": "Not part of default discovery. The page says Codex also reads names listed in project_doc_fallback_filenames and ignores names not on that list.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "codex",
      "file": "cursorrules",
      "status": "configurable",
      "note": "Not part of default discovery. The page says Codex also reads names listed in project_doc_fallback_filenames and ignores names not on that list.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "codex",
      "file": "cursor-rules-mdc",
      "status": "unverified",
      "note": "Not mentioned on the cited page, or in the configuration reference entry for project_doc_fallback_filenames, when checked.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "codex",
      "file": "claude-rules",
      "status": "unverified",
      "note": "Not mentioned on the cited page, or in the configuration reference entry for project_doc_fallback_filenames, when checked.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "codex",
      "file": "copilot-instructions-md",
      "status": "unverified",
      "note": "The page says Codex checks fallback names from project_doc_fallback_filenames in each directory from the project root to the working directory. It does not say whether a path such as .github/copilot-instructions.md can be listed.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "codex",
      "file": "copilot-path-instructions",
      "status": "unverified",
      "note": "Not mentioned on the cited page, or in the configuration reference entry for project_doc_fallback_filenames, when checked.",
      "sourceUrl": "https://learn.chatgpt.com/docs/agent-configuration/agents-md",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "github-copilot",
      "file": "agents-md",
      "status": "reads",
      "note": "Agent instructions: one or more AGENTS.md files anywhere in the repository; the nearest file in the directory tree takes precedence.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "github-copilot",
      "file": "agents-override-md",
      "status": "unverified",
      "note": "Not mentioned on the cited page or in GitHub's \"Support for different types of custom instructions\" table when checked. That table names copilot-instructions.md, *.instructions.md, AGENTS.md, CLAUDE.md, GEMINI.md and, for code review, REVIEW.md.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "github-copilot",
      "file": "claude-md",
      "status": "reads",
      "note": "Alternative to AGENTS.md: a single CLAUDE.md in the repository root.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "github-copilot",
      "file": "gemini-md",
      "status": "reads",
      "note": "Alternative to AGENTS.md: a single GEMINI.md in the repository root.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "github-copilot",
      "file": "cursorrules",
      "status": "unverified",
      "note": "Not mentioned on the cited page or in GitHub's \"Support for different types of custom instructions\" table when checked. That table names copilot-instructions.md, *.instructions.md, AGENTS.md, CLAUDE.md, GEMINI.md and, for code review, REVIEW.md.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "github-copilot",
      "file": "cursor-rules-mdc",
      "status": "unverified",
      "note": "Not mentioned on the cited page or in GitHub's \"Support for different types of custom instructions\" table when checked. That table names copilot-instructions.md, *.instructions.md, AGENTS.md, CLAUDE.md, GEMINI.md and, for code review, REVIEW.md.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "github-copilot",
      "file": "claude-rules",
      "status": "unverified",
      "note": "Not mentioned on the cited page or in GitHub's \"Support for different types of custom instructions\" table when checked. That table names copilot-instructions.md, *.instructions.md, AGENTS.md, CLAUDE.md, GEMINI.md and, for code review, REVIEW.md.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-16"
    },
    {
      "tool": "github-copilot",
      "file": "copilot-instructions-md",
      "status": "reads",
      "note": "Repository-wide instructions in .github/copilot-instructions.md.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-15"
    },
    {
      "tool": "github-copilot",
      "file": "copilot-path-instructions",
      "status": "reads",
      "note": "NAME.instructions.md files under .github/instructions with an applyTo glob. On GitHub.com, supported for the cloud agent and code review only.",
      "sourceUrl": "https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions",
      "verifiedOn": "2026-10-15"
    }
  ]
}