Creating Claude Rules

Overview

Rules in .claude/rules/ are modular instructions scoped to specific files via glob patterns. They load automatically with same priority as CLAUDE.md.

When to Use

• Creating new rules in .claude/rules/
• Fixing rules that use wrong frontmatter (globs instead of paths)
• Migrating Cursor rules to Claude format
• Organizing project-specific conventions

Quick Reference

Field	Claude	Cursor
Path patterns	paths	globs
Always apply	Omit paths	alwaysApply: true
Description	Not documented	description

Frontmatter

Path-Scoped Rules

---
paths:
  - 'src/api/**/*.ts'
  - 'tests/**/*.test.ts'
---

Or single pattern:

---
paths: src/**/*.{ts,tsx}
---

Global Rules

Omit frontmatter entirely - applies to all files:

# TypeScript Conventions

Use .js extensions in imports.

Common Mistakes

# ❌ WRONG - globs is Cursor format
---
globs:
  - '**/*.ts'
---
# ✅ CORRECT - Claude uses paths
---
paths:
  - '**/*.ts'
---

# ❌ WRONG - alwaysApply is Cursor-only
---
alwaysApply: true
---
# ✅ CORRECT - just omit paths for global rules
# (no frontmatter needed)

# ❌ WRONG - unquoted patterns
---
paths:
  - **/*.ts
---

# ✅ CORRECT - quote glob patterns
---
paths:
  - "**/*.ts"
---

Directory Structure

.claude/rules/
├── testing.md          # Path-scoped or global
├── typescript.md
└── frontend/           # Subdirectories supported
    └── react.md

Files discovered recursively. Use subdirectories to organize.

Glob Patterns

Pattern	Matches
**/*.ts	All .ts files anywhere
src/**/*	Everything under src/
*.md	Markdown in root only
**/*.{ts,tsx}	.ts and .tsx files
{src,lib}/**/*.ts	.ts in src/ or lib/

Reference

https://code.claude.com/docs/en/memory#modular-rules-with-claude/rules/