MD046 - Use Consistent Code Block Style¶

Aliases: code-block-style

What this rule does¶

Ensures all code blocks in your document:

Use the same style - either fenced (with backticks) or indented (with spaces)
Are properly closed when using fenced style

Why this matters¶

Readability: Mixing styles makes documents harder to scan and understand
Maintainability: Consistent style makes code blocks easier to edit
Tool compatibility: Some tools work better with one style over another
Professional appearance: Consistency shows attention to detail

Examples¶

✅ Correct (Fenced style)¶

Here's how to use our API:

```javascript
const api = require('our-api');
api.connect();
```

And here's the response format:

```json
{
  "status": "success",
  "data": {}
}
```

❌ Incorrect (Mixed styles)¶

Here's how to use our API:

```javascript
const api = require('our-api');
api.connect();
```

And here's the response format:

    {
      "status": "success",
      "data": {}
    }

🔧 Fixed (Mixed styles)¶

Here's how to use our API:

```javascript
const api = require('our-api');
api.connect();
```

And here's the response format:

```json
{
  "status": "success",
  "data": {}
}
```

❌ Incorrect (Unclosed code block)¶

```javascript
const api = require('our-api');
api.connect();

Some text after the code that was meant to be outside the block.

🔧 Fixed (Unclosed code block)¶

```javascript
const api = require('our-api');
api.connect();
```

Some text after the code that was meant to be outside the block.

❌ Incorrect (Missing closing fence before new block)¶

```javascript
const api = require('our-api');
api.connect();

```python
print("hello")
```

🔧 Fixed (Missing closing fence before new block)¶

```javascript
const api = require('our-api');
api.connect();
```

```python
print("hello")
```

Configuration¶

[MD046]
style = "consistent"  # Options: "consistent", "fenced", "indented"

Style options¶

Value	Description
`consistent`	All code blocks must use the same style (default)
`fenced`	All code blocks must use fenced style (``` or _~)
`indented`	All code blocks must use indented style (4 spaces)

Automatic fixes¶

When enabled, this rule will:

Convert all code blocks to match your configured style
Preserve code content and language identifiers
Maintain proper spacing around blocks
Close fenced code blocks that are missing a closing fence
Insert closing fences when a new code block opens before the previous one is closed

Style comparison¶

Fenced code blocks (recommended):

Support syntax highlighting with language identifiers
Easier to copy and paste
More visible boundaries

Indented code blocks:

Traditional Markdown style
No language identifier support
Must indent each line with 4 spaces or 1 tab

Special cases¶

Empty code blocks are ignored
HTML <pre> and <code> tags are not affected
When using "consistent", the most prevalent style is used (in case of a tie, fenced style is preferred as it's more widely supported)
Per CommonMark, fenced code block openers (``` or ~~~) can only have 0-3 spaces of indentation. With 4+ spaces, the fence markers become literal content in an indented code block
Unclosed-block detection is skipped in documents containing markdown or md code blocks, since these often include fence examples that would be misdetected

Azure DevOps / Colon Fences¶

Under the azure_devops flavor, colon-style fences (... :::) are excluded from code block style detection. They are not counted toward the dominant style and are never flagged as style violations. This prevents false positives when a document mixes colon fences with backtick or tilde fences:

::: mermaid
sequenceDiagram
    Alice->>Bob: Hello
:::

```python
print("hello")
```

In this example, only the backtick fence counts for style detection. The colon fence is treated as opaque block content and ignored by MD046.

Under any other flavor, colon fences are not recognized and do not affect style detection.

See Azure DevOps Flavor for the full colon fence specification.

Learn more¶

MD031 - Add blank lines around code blocks
MD040 - Specify languages for code blocks
MD048 - Use consistent fence markers (backticks vs tildes)