| name | markdown-accessibility |
| description | Audit and fix markdown for accessibility. Covers ambiguous links, anchors, emoji (remove/translate), Mermaid/ASCII templates, heading hierarchy, table descriptions, and severity scoring. |
Markdown Accessibility Skill
Reusable knowledge module for the markdown-a11y-assistant, markdown-scanner, and markdown-fixer agents and the markdown-accessibility always-on instructions. Provides pattern libraries, severity scoring, fix templates, emoji translation maps, diagram description templates, and GitHub anchor generation rules for comprehensive markdown accessibility auditing across 9 domains.
Domains Covered
- Descriptive Links (WCAG 2.4.4) - Ambiguous link text, bare URLs, repeated identical text
- Image Alt Text (WCAG 1.1.1) - Missing, empty, filename-as-alt, generic placeholders
- Heading Hierarchy (WCAG 1.3.1 / 2.4.6) - Skipped levels, multiple H1s, bold-as-heading
- Table Accessibility (WCAG 1.3.1) - Missing descriptions, empty headers, layout tables
- Emoji (WCAG 1.3.3 / Cognitive) - Remove-all, remove-decorative, translate, or leave-unchanged modes
- Mermaid and ASCII Diagrams (WCAG 1.1.1 / 1.3.1) - Replace with accessible text + collapsible source
- Em-Dash / En-Dash Normalization (Cognitive) - Normalize to
- or leave unchanged
- Anchor Link Validation (WCAG 2.4.4) - Validate
#anchor links against actual headings
- Plain Language and List Structure (Cognitive) - Emoji bullets, passive voice, sentence length
Severity Scoring
| Issue | Severity | WCAG | Auto-fix? |
|---|
| Image missing alt text | Critical | 1.1.1 (A) | No - needs visual judgment |
| Mermaid diagram with no text alternative | Critical | 1.1.1 (A) | Partial - simple diagrams auto-described; complex need human |
| ASCII diagram with no text description | Critical | 1.1.1 (A) | Partial - flag and wrap; description needs human or auto-gen |
| Broken anchor link | Serious | 2.4.4 (A) | No - confirm which end changes |
| Ambiguous link text ("here", "click here") | Serious | 2.4.4 (A) | Yes - rewrite using surrounding context |
| Skipped heading level | Serious | 1.3.1 (A) | Yes - interpolate missing level |
| Multiple H1s | Serious | 1.3.1 (A) | Yes - demote all but first |
| Emoji in heading | Moderate | Cognitive | Yes - remove or translate per preference |
| Consecutive emoji (2+) | Moderate | 1.3.3 (A) | Yes - remove sequence or translate |
| Emoji used as bullet | Moderate | 1.3.1 (A) | Yes - replace with - |
| Em-dash in prose | Moderate | Cognitive | Yes - replace with - |
| Table without preceding description | Moderate | 1.3.1 (A) | Yes - add one-sentence summary |
| Bold text used as heading | Minor | 2.4.6 (AA) | Yes - convert to appropriate heading |
| Bare URL in prose | Minor | 2.4.4 (A) | Yes - wrap with descriptive text |
| Emoji used for meaning, single inline | Minor | 1.3.3 (A) | Conditional - remove-all: yes; remove-decorative: flag; translate: translate |
Scoring Formula
File Score = 100 - (sum of weighted findings)
Critical: -15 pts each
Serious: - 7 pts each
Moderate: - 3 pts each
Minor: - 1 pt each
Floor: 0
Score Grades
| Score | Grade | Meaning |
|---|
| 90-100 | A | Excellent - accessible documentation |
| 75-89 | B | Good - minor issues |
| 50-74 | C | Needs Work - several barriers |
| 25-49 | D | Poor - significant barriers |
| 0-24 | F | Failing - critical AT barriers |
Emoji Handling Modes
The agent supports four modes. The active mode is determined by the nearest markdown-accessibility.instructions.md file in scope. If no instructions file sets a mode, the default is remove-decorative.
This repository: The .github/instructions/markdown-accessibility.instructions.md file in this repo sets mode to remove-all. All emoji are removed, not translated. This overrides the skill default.
| Mode | Description | Default? |
|---|
remove-all | Strip every emoji from prose, headings, and bullets. Keep surrounding plain-text meaning. | No (repo override sets this) |
remove-decorative | Remove emoji in headings, bullets, and consecutive sequences; flag single inline for review | Skill default (no override) |
translate | Replace known emoji with (English) text; flag unknown for review | No |
leave-unchanged | Do not flag or modify any emoji | No |
Mode resolution order:
- Agent system prompt or per-task explicit mode override
- Nearest
*.instructions.md file in scope (e.g., .github/instructions/markdown-accessibility.instructions.md)
- Skill default (
remove-decorative)
Emoji Translation Map
When using translate mode, replace each emoji with the parenthesized English equivalent:
| Emoji | Translation | Emoji | Translation |
|---|
| ๐ | (Launch) | โ
| (Done) |
| โ ๏ธ | (Warning) | โ | (Error) |
| ๐ | (Note) | ๐ก | (Tip) |
| ๐ง | (Configuration) | ๐ | (Documentation) |
| ๐ฏ | (Goal) | โจ | (New) |
| ๐ | (Search) | ๐ ๏ธ | (Tools) |
| ๐ | (Hello) | ๐ | (Celebration) |
| โญ | (Featured) | ๐ฌ | (Discussion) |
| ๐ | (Home) | ๐ | (Data) |
| ๐ | (Security) | ๐ | (Web) |
| ๐ฆ | (Package) | ๐ | (Link) |
| ๐ | (Checklist) | ๐ | (Achievement) |
| โก | (Quick) | ๐ | (Approved) |
| ๐ | (Rejected) | ๐ | (Bug) |
| ๐ค | (Collaboration) | ๐ | (Learning) |
| ๐ | (Key) | ๐ | (Pinned) |
| โน๏ธ | (Info) | ๐ | (Refresh) |
| โ | (Add) | โ | (Remove) |
| ๐ป | (Code) | ๐ | (Notification) |
| ๐ฃ | (Announcement) | ๐งช | (Test) |
| ๐จ | (Design) | ๐ | (Highlight) |
| ๐ | (Increase) | ๐ | (Decrease) |
| ๐๏ธ | (Build) | ๐ | (Locked) |
| ๐ | (Folder) | ๐ | (Folder) |
| ๐๏ธ | (Category) | ๐๏ธ | (Archive) |
| โ๏ธ | (Settings) | ๐ | (Finish) |
| ๐ง | (In Progress) | ๐ซ | (Not Allowed) |
| โ๏ธ | (Check) | โก๏ธ | (Next) |
| โฌ๏ธ | (Up) | โฌ๏ธ | (Down) |
For emoji not in this table: flag as needs-human-review. Do not guess.
Emoji Detection Unicode Ranges
[\u{1F600}-\u{1F64F}] - Emoticons
[\u{1F300}-\u{1F5FF}] - Misc symbols and pictographs
[\u{1F680}-\u{1F6FF}] - Transport and map symbols
[\u{1F700}-\u{1F77F}] - Alchemical symbols
[\u{1F780}-\u{1F7FF}] - Geometric shapes extended
[\u{1F900}-\u{1F9FF}] - Supplemental symbols
[\u{1FA70}-\u{1FAFF}] - Symbols and pictographs extended
[\u{2600}-\u{26FF}] - Misc symbols
[\u{2700}-\u{27BF}] - Dingbats
[\u{1F1E0}-\u{1F1FF}] - Flags
[\u{FE00}-\u{FE0F}] - Variation selectors
Emoji-as-bullet pattern: list item where the first non-whitespace character is an emoji.
Pattern Library: Mermaid and ASCII Diagrams
Mermaid Detection
Lines matching ```mermaid (with optional leading spaces/tabs).
Mermaid Description Templates
| Type | Description Template |
|---|
graph TD/LR/RL/BT / flowchart | "The following [direction] diagram shows: [list major nodes and connections from source]" |
sequenceDiagram | "The following sequence diagram shows the interaction between [participants]: [list each message in order]" |
classDiagram | "The following class diagram shows [N] classes: [list class names, key properties, and relationships]" |
erDiagram | "The following entity-relationship diagram shows [entities] with these relationships: [list relationships]" |
gantt | "The following Gantt chart shows project tasks: [list section names and tasks with dates if available]" |
pie | "The following pie chart shows [title] with values: [list each label and percentage/value if available]" |
stateDiagram | "The following state diagram shows [N] states: [list state names and transition triggers]" |
mindmap | "The following mind map shows [root topic] with branches: [list top-level branch names]" |
timeline | "The following timeline shows events: [list events in chronological order]" |
Auto-generate description for: graph, flowchart, pie, gantt, mindmap, timeline.
Flag for human review: sequenceDiagram, classDiagram, erDiagram, stateDiagram (complex enough to need human verification).
Mermaid Replacement Template
[Generated or user-provided text description - this is the primary accessible content]
<details>
<summary>Diagram source (Mermaid)</summary>
````mermaid
[original diagram source - unchanged]
```text
</details>
````
### ASCII Diagram Detection
ASCII art patterns: non-code-block lines (or unnamed code blocks) containing combinations of `+`, `-`, `|`, `/`, `\`, `>`, `<`, `^`, `v`, `*` forming a visual structure. Minimum 3 lines with consistent column alignment.
### ASCII Diagram Replacement Template
```markdown
[Generated or user-provided text description - this is the primary accessible content]
<details>
<summary>ASCII diagram</summary>
```
[original ASCII art - unchanged]
```html
</details>
```
## Pattern Library: Ambiguous Link Detection
Match these patterns (case-insensitive, trim whitespace):
### Exact-match violations
```text
here, click here, read more, learn more, more, more info,
link, details, info, go, see more, continue, start, download,
view, open, submit, this, that
```
### Starts-with violations
```text
click here to ..., read more about ..., learn more about ...,
here to ..., see more ...
```
### URL-as-text pattern
Any link where visible text matches `https?://` or `www\.`
### Repeated identical text
Multiple `[X](url1)` and `[X](url2)` with same X but different URLs on the same page.
### Safe patterns (do not flag)
- Badge links: `[](url)` at top of README
- Section self-references: `[Installation](#installation)` where text matches heading
- Footer resource lists using the resource/tool name as text
## Pattern Library: GitHub Anchor Generation
GitHub converts headings to anchor IDs using these rules:
1. Lowercase entire string
2. Remove all characters except: letters (a-z), digits (0-9), spaces, hyphens
3. Replace spaces with hyphens
4. Remove leading and trailing hyphens
### Examples
| Heading | Anchor |
| ------------------------------------- | ----------------------------------------------- |
| `# Getting Started` | `#getting-started` |
| `## API: v2.0 Reference` | `#api-v20-reference` |
| `### What's New?` | `#whats-new` |
| `## C# and .NET Support` | `#c-and-net-support` |
| `## Step 1: Installation` | `#step-1-installation` |
| `## FAQ (Frequently Asked Questions)` | `#faq-frequently-asked-questions` |
| `## ๐ Quick Start` | `#-quick-start` (emoji becomes empty, may vary) |
For headings containing emoji: GitHub strips the emoji character and generates an anchor from the remaining text. Anchors referencing emoji-containing headings are fragile and should be flagged.
## Pattern Library: Emoji Detection
Unicode emoji ranges for regex detection:
```text
[\u{1F600}-\u{1F64F}] # Emoticons
[\u{1F300}-\u{1F5FF}] # Misc symbols and pictographs
[\u{1F680}-\u{1F6FF}] # Transport and map symbols
[\u{1F700}-\u{1F77F}] # Alchemical symbols
[\u{1F780}-\u{1F7FF}] # Geometric shapes extended
[\u{1F800}-\u{1F8FF}] # Supplemental arrows-C
[\u{1F900}-\u{1F9FF}] # Supplemental symbols and pictographs
[\u{1FA00}-\u{1FA6F}] # Chess symbols
[\u{1FA70}-\u{1FAFF}] # Symbols and pictographs extended-A
[\u{2600}-\u{26FF}] # Misc symbols
[\u{2700}-\u{27BF}] # Dingbats
[\u{FE00}-\u{FE0F}] # Variation selectors
[\u{1F1E0}-\u{1F1FF}] # Flags
```
Emoji-as-bullet pattern: List item where first non-whitespace character is an emoji.
## Pattern Library: Em-Dash and En-Dash
Detection patterns:
```text
โ Unicode em-dash (U+2014)
โ Unicode en-dash (U+2013)
--- Three hyphens in prose (not on its own line as HR)
-- Two hyphens in prose (used as em-dash substitute)
```
Safe to skip (do not modify):
- Line containing only `---` (horizontal rule)
- Content inside ` ``` ` code fences
- Content inside backtick inline code
- YAML front matter block
- HTML comment blocks `<!-- -->`
Replacement: `-` (space + hyphen + space)
En-dash in numeric ranges: `2โ4 hours` -> `2 - 4 hours`
## Pattern Library: Mermaid Diagrams
Detection: Lines matching ` ```mermaid` (with optional leading spaces/tabs)
Diagram types and description guidance:
| Type | Description Template |
| ------------------- | ---------------------------------------------------------------------------------------------------------- |
| `graph TD/LR/RL/BT` | "The following diagram shows a [direction] flowchart: [list major nodes and connections]" |
| `sequenceDiagram` | "The following sequence diagram shows the interaction between [participants]: [list message exchanges]" |
| `classDiagram` | "The following class diagram shows [N] classes: [list class names and key relationships]" |
| `erDiagram` | "The following entity-relationship diagram shows [entities] and their relationships: [list relationships]" |
| `gantt` | "The following Gantt chart shows project phases: [list tasks and timeframes]" |
| `pie` | "The following pie chart shows [title] with values: [list segment names and values if available]" |
| `stateDiagram` | "The following state diagram shows [N] states and transitions: [list states and transition triggers]" |
Wrapping template:
````markdown
[Generated or user-provided text description]
<details>
<summary>Diagram source (Mermaid)</summary>
````mermaid
[original diagram source]
```text
</details>
## Fix Templates
### Ambiguous link fix
```markdown
# Before
For more information, see [here](https://example.com/guide).
# After
For more information, see the [installation guide](https://example.com/guide).
```
### Emoji bullet fix
```markdown
# Before
- ๐ Deploy to production
- โ
Run tests
# After
- Deploy to production
- Run tests
```
### Emoji heading fix
```markdown
# Before
## ๐ง Configuration
# After
## Configuration
```
### Em-dash fix
```markdown
# Before
The agentโwhen invokedโwill scan all files.
# After
The agent - when invoked - will scan all files.
```
### Table description fix
```markdown
# Before
| Rule | Severity | Auto-fix |
| ---- | -------- | -------- |
# After
The following table lists rules with their severity level and whether they can be fixed automatically.
| Rule | Severity | Auto-fix |
| ---- | -------- | -------- |
```
### Broken anchor fix
```markdown
# Before (broken)
See [Installation](#instalation) for setup steps.
# Heading in file
## Installation
# After (corrected)
See [Installation](#installation) for setup steps.
```
## Markdownlint Rules Reference
| Rule | Name | Accessibility Relevance |
| ----- | ------------------------ | ------------------------------------ |
| MD001 | heading-increment | Heading hierarchy (WCAG 1.3.1) |
| MD022 | blanks-around-headings | Parsing reliability |
| MD024 | no-duplicate-heading | Unique section identity (WCAG 2.4.6) |
| MD025 | single-title / single-h1 | One H1 per document |
| MD033 | no-inline-html | May hide structure from parsers |
| MD034 | no-bare-urls | Ambiguous links (WCAG 2.4.4) |
| MD041 | first-line-heading | Document structure |
| MD055 | table-pipe-style | Table parsing consistency |
| MD056 | table-column-count | Table structural integrity |
Command: `npx --yes markdownlint-cli2 <filepath>`
