Accessibility Pass

microsoft/accessibility-pass

>- Use this skill whenever the user asks to check, review, or fix the accessibility of a PowerPoint deck, Word document, HTML page, or Markdown file, and before handing over any deck or document this agent just generated, so it does not ship with missing alt text, untitled slides, or unreadable colour contrast.

8k tokens

context cost

the whole folder, loaded on every use

files

ships runnable scripts

copies elsewhere

how many repositories repackaged it

7 d ago

last touched

this folder, not the whole repository

Install

one command, takes just this skill from the repository

npx skills add https://github.com/microsoft/cat-agent-skills --skill accessibility-pass

What comes with it

26 475 bytes besides the instruction

README.md

metadata.json

scripts/a11y_check.py

The instruction itself

4 sections, as written by the author

Review the artefact against Microsoft's Accessibility Checker rules, report what

fails, and fix it on request. Use the rule names below verbatim. They are the

same ones the author sees when they run the checker themselves in Office, so the

findings are recognisable and searchable.

Instructions

Get the file. Supported: .pptx, .docx, .html, .md. If the user pasted

raw HTML or Markdown instead, save it to a file first.

Run the bundled checker when a Python environment is available, from the

skill's own root directory (the folder containing scripts/), so the

relative path resolves:

   python scripts/a11y_check.py <file> --json

It needs python-pptx for .pptx and python-docx for .docx; HTML and

Markdown need nothing beyond the standard library. If the environment has

no Python, or the import fails: for HTML and Markdown, read the file

directly and check it against the rules below by hand. For .pptx and

.docx, that fallback doesn't really work, these are zipped Office XML,

not something to eyeball as text, so instead say plainly that the file

couldn't be checked, and ask the user to run Office's own Accessibility

Checker (File > Info > Check for Issues > Check Accessibility) and share

what it reports.

Add the judgement calls the script deliberately does not make:

Alt text that exists but is useless. "image1.png", "chart", or a

filename is a failure even though the attribute is populated. Read every

alt string and judge whether someone who cannot see the image learns the

same thing from it.

Wrongly decorative. Anything marked decorative that actually carries

information is a failure the script cannot see.

Reading order that is flagged but fine. The script compares screen-reader

order with visual top-left order; deliberate multi-column layouts trip it.

Confirm before reporting.

Meaning carried by colour alone, such as red/green status dots or "the

items in orange," which no file-level check can detect.

Captions and transcripts for embedded audio or video.
Contrast the script skipped. It only compares explicit RGB values.

Theme colours, gradients, and picture fills come back unchecked. Report

them as unchecked, never as passing.

Report findings grouped by severity, worst first, one row each:

| --- | --- | --- | --- |

Open with a one-line count (3 errors, 5 warnings, 1 tip). If nothing fails,

say so and list what could not be checked mechanically.

Offer to apply the fixes. Apply directly: adding a missing slide title, adding

a table header row, rewriting vague link text, adding lang to <html>,

fixing heading-level jumps. Ask first before writing alt text for an image

whose content is uncertain, marking anything decorative, changing colours, or

restructuring merged tables, since each of those changes meaning or design.

Re-run the checker after fixing and report what is left.

The rules

Errors: content that is unusable for someone relying on assistive tech.

All non-text content has alternative text (alt text)
Tables specify column header information
All slides have titles
All sections have meaningful names *(the bundled script doesn't check this;

ask the user or inspect the file's sections manually)*

Document access is not restricted *(the bundled script doesn't check this;

verify manually whether the file has IRM/password protection applied)*

Warnings: content that is hard to use.

Sufficient contrast between text and background (WCAG AA: 4.5:1 normal text,

3:1 for text 18pt+ or bold 14pt+)

Table has a simple structure
The reading order of the objects on a slide presentation is logical
Closed captions are included for inserted audio and video
Hyperlink text is meaningful

Tips: content that could be easier to use.

Slide titles in a deck are unique
Documents use heading styles
Document language is set

Guardrails

Never invent alt text for an image whose content is unknown. Ask the user what

it shows, or describe only what surrounding text supports and say the

description needs confirming.

Never mark an object decorative to clear a finding. Decorative means it carries

no information; use it only when that is true.

Never edit visible wording, layout, or branding beyond what a fix requires.
Never report an unchecked item as a pass.
Do not claim WCAG or EN 301 549 conformance. This is a pass over known rules,

not a certification. A clean result means no *detected* issues.

Tone

Direct and specific. Name the rule, the location, and the concrete fix. No

lecturing about why accessibility matters; the user already asked.

How to use it

Copy the folder

Take microsoft/accessibility-pass from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.