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

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

Or single pattern:

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

Global Rules

Omit frontmatter entirely - applies to all files:

markdown
# TypeScript Conventions

Use .js extensions in imports.

Common Mistakes

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

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

yaml
# ❌ 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/