Project Rules Files Compared

.cursorrules, CLAUDE.md, .clinerules, copilot-instructions — what each does and how to share.

WorkflowBeginner

Why

GitHub's 2024 enterprise survey of 2,000 developers found 97% have used AI coding tools at work, and Stack Overflow's 2024 survey found 76% of developers use or plan AI tools (up from 70%). Every major AI tool reads a project rules file, but the filenames differ.

Knowing the mapping lets you write one set of conventions and wire it to each tool, so the whole team gets consistent output regardless of tool.

When

Set up rules files when the team uses multiple AI tools, or when output doesn't match conventions. Avoid this workflow for trivial one-off edits where opening an AI tool adds more overhead than value.

How

1. .cursorrules — Cursor (root, plain text). 2. CLAUDE.md — Claude Code (root, markdown, auto-loaded). 3. .clinerules — Cline (root, plain text). 4. .github/copilot-instructions.md — Copilot (repo, markdown). 5. .windsurfrules — Windsurf (root, plain text). 6. Keep a canonical source and symlink/copy to the others.

Example

# Canonical: AGENTS.md (shared) Stack: Astro 7 + React 18, TS strict. Data in src/data/*.ts. Named exports. # .cursorrules -> symlink to AGENTS.md # CLAUDE.md -> symlink to AGENTS.md # .github/copilot-instructions.md -> symlink to AGENTS.md

Common Problems

⚠Error: Cannot find module 'xxx' → run `npm install xxx` (or `pnpm add xxx`); verify it is in package.json dependencies.
⚠Error: "Command not found: claude" or "cursor" → ensure the binary is on PATH: `which claude` / `which cursor`; reinstall globally if missing.
⚠TypeError: Cannot read properties of undefined (reading 'x') → add a null guard or optional chaining `obj?.x`; trace the undefined source via the stack.

Best Practices

✓Use one canonical file (e.g., AGENTS.md) and symlink tool-specific names to it.
✓Commit rules files and review changes in PRs.
✓Measure the outcome with a concrete metric (time saved, defect rate, test coverage) so the practice can be justified and improved.

FAQ

What is Project Rules Files Compared?

.cursorrules, CLAUDE.md, .clinerules, copilot-instructions — what each does and how to share. It helps developers quickly grasp the core value and use cases of Project Rules Files Compared.

How do I get started with Project Rules Files Compared?

To get started with Project Rules Files Compared, focus on these points first: .cursorrules — Cursor (root, plain text).

What are common mistakes with Project Rules Files Compared?

Common mistakes when using Project Rules Files Compared include: Error: Cannot find module 'xxx' → run `npm install xxx` (or `pnpm add xxx`); verify it is in package.json dependencies.; Error: "Command not found: claude" or "cursor" → ensure the binary is on PATH: `which claude` / `which cursor`; reinstall globally if missing.; TypeError: Cannot read properties of undefined (reading 'x') → add a null guard or optional chaining `obj?.x`; trace the undefined source via the stack..

What are the best practices for Project Rules Files Compared?

Best practices for Project Rules Files Compared include: Use one canonical file (e.g., AGENTS.md) and symlink tool-specific names to it.; Commit rules files and review changes in PRs.; Measure the outcome with a concrete metric (time saved, defect rate, test coverage) so the practice can be justified and improved..

How do I learn more about Project Rules Files Compared?

Start with the official docs, then search real-world examples on GitHub. Validate patterns in a small scratch repo before applying them to production code.