MDBOOK004 - No Duplicate Chapter Titles
Chapter titles should be unique across the book.
Why This Rule Exists
Duplicate chapter titles create confusion in navigation and can cause issues with mdBook's URL generation. Each chapter should have a distinct, identifiable title.
Examples
Incorrect (SUMMARY.md)
# Summary
- [Introduction](./intro.md)
- [Getting Started](./start.md)
- [Introduction](./advanced-intro.md) <!-- Duplicate -->
Correct
# Summary
- [Introduction](./intro.md)
- [Getting Started](./start.md)
- [Advanced Introduction](./advanced-intro.md)
Configuration
This rule has no configuration options.
When to Disable
- Books with intentionally repeated section names
- Multi-part books where repetition is meaningful
Rule Details
- Rule ID: MDBOOK004
- Aliases: no-duplicate-chapter-titles
- Category: MdBook
- Severity: Warning
- Auto-fix: No
Impact
Duplicate titles can cause:
- Confusing navigation sidebar
- Ambiguous URL paths
- Search result confusion
- Poor user experience