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MDBOOK006 - Internal Cross-References

Internal cross-reference links must point to valid headings in target files.

Why This Rule Exists

Cross-references between chapters using anchor fragments must resolve to actual headings in the target file. Invalid fragments create broken navigation.

Examples

Incorrect

See the [configuration section](./config.md#settings) for details.

Where config.md has no ## Settings heading.

Correct

See the [configuration section](./config.md#configuration-options) for details.

Where config.md contains:

## Configuration Options

Content here.

How Fragments Are Generated

mdBook generates fragments from headings:

HeadingFragment
## Getting Started#getting-started
## API Reference#api-reference
## What's New?#whats-new

Configuration

This rule has no configuration options.

When to Disable

  • Books using custom anchor IDs
  • Content with JavaScript-based navigation

Rule Details

  • Rule ID: MDBOOK006
  • Aliases: internal-cross-references
  • Category: MdBook
  • Severity: Warning
  • Auto-fix: No
  • MD051 - Link fragments (same-file)
  • MDBOOK002 - Internal link validation