MD066 - Footnote validation¶

Aliases: footnote-validation

What this rule does¶

Checks that all footnote references have corresponding definitions and vice versa.

Why this matters¶

Prevents broken footnotes: References without definitions leave readers confused
Avoids clutter: Unused definitions add noise to your document
Ensures completeness: All footnotes work as intended
Improves accessibility: Screen readers can follow properly linked footnotes

Examples¶

Correct¶

This text has a footnote[^1] that is properly defined.

Another reference[^note] works too.

[^1]: This is the first footnote.
[^note]: Named footnotes are also valid.

Incorrect - orphaned reference¶

This references[^missing] a footnote that doesn't exist.

Warning: Footnote reference [^missing] has no corresponding definition

Incorrect - orphaned definition¶

Some text without any footnote references.

[^unused]: This footnote is defined but never referenced.

Warning: Footnote definition [^unused] is never referenced

Configuration¶

This rule has no configuration options.

Automatic fixes¶

This rule cannot automatically fix issues because:

Missing definitions require you to provide the footnote content
Unused definitions might be intentional placeholders or copy-paste errors

Footnote syntax¶

Footnotes are a common markdown extension (not part of CommonMark):

Reference: [^identifier] placed inline in text
Definition: [^identifier]: content at the start of a line

Footnote definitions can span multiple lines with indentation:

[^long]: This is a multi-line footnote.

    Additional paragraphs are indented with 4 spaces.

    You can include code blocks and other content.