MD001 - Header levels should only increment by one level at a time

Tags: headers

Aliases: header-increment

This rule is triggered when you skip header levels in a markdown document, for example:

# Header 1

### Header 3

We skipped out a 2nd level header in this document

When using multiple header levels, nested headers should increase by only one level at a time:

# Header 1

## Header 2

### Header 3

#### Header 4

## Another Header 2

### Another Header 3

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

MD036 - Emphasis used instead of a header

Tags: headers, emphasis

Parameters: punctuation (string; default ".,;:!?")

Aliases: no-emphasis-as-header

This check looks for instances where emphasized (i.e. bold or italic) text is used to separate sections, where a header should be used instead:

**My document**

Lorem ipsum dolor sit amet...

_Another section_

Consectetur adipiscing elit, sed do eiusmod.

To fix this, use markdown headers instead of emphasized text to denote sections:

# My document

Lorem ipsum dolor sit amet...

## Another section

Consectetur adipiscing elit, sed do eiusmod.

Note: this rule looks for single line paragraphs that consist entirely of emphasized text. It won't fire on emphasis used within regular text, multi-line emphasized paragraphs, and paragraphs ending in punctuation. Similarly to rule MD026, you can configure what characters are recognized as punctuation.