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eliaalberti/ux-audit-skill

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Heuristic UX audits from screenshots for Claude Code & Codex with severity-rated findings, heuristic citations, annotated screenshots, structured reports.

Overview

🔍 UX Audit Skill Heuristic UX audits from screenshots Point it at screenshots of a user journey. Get severity-rated findings, heuristic citations, annotated screenshots, and a structured report. Graded against 16 named UX frameworks, not vibes. One skill, runs in both Claude Code and Codex.    Example output: a two-screen journey audited and annotated by severity (red = critical, orange = major, amber = minor, green = positive). What You Get • Why It Works • Frameworks • Installation • Usage • Severity • FAQ You give the skill screenshots of a flow and one line about what the user is trying to do. It returns: - on Nielsen's 0 to 4 scale, anchored to the user's actual goal - on every finding ("Nielsen #5", "WCAG 1.4.

README

🔍 UX Audit Skill Heuristic UX audits from screenshots

Point it at screenshots of a user journey. Get severity-rated findings, heuristic citations, annotated screenshots, and a structured report. Graded against 16 named UX frameworks, not vibes. One skill, runs in both Claude Code and Codex.

  

Example output: a two-screen journey audited and annotated by severity (red = critical, orange = major, amber = minor, green = positive).

What You Get • Why It Works • Frameworks • Installation • Usage • Severity • FAQ


What You Get

You give the skill screenshots of a flow and one line about what the user is trying to do. It returns:

  • Severity-rated findings on Nielsen’s 0 to 4 scale, anchored to the user’s actual goal
  • Heuristic citations on every finding (“Nielsen #5”, “WCAG 1.4.3”, “Hick’s Law”), never generic “make it pop” feedback
  • Annotated screenshots with numbered, colour-coded markers
  • Recommended fixes with effort estimates (S/M/L)
  • A structured Markdown report with an executive summary, screen-by-screen findings, journey-level analysis, and what already works

It’s a heuristic evaluation, the kind a senior designer does, run by an agent that has actually looked at your screens.


What Are Agent Skills?

A skill is a folder with a SKILL.md file. The agent reads it and follows the instructions when a task matches. No plugin, no code to wire up. This one bundles a small Python script for the annotation step.

The same skill folder works in both tools. They read skills from different directories:

Tool Skills folder
Claude Code ~/.claude/skills/ux-audit/
Codex ~/.codex/skills/ux-audit/

Both tools auto-invoke the skill when you ask for a UX audit. In Claude Code you can also call it explicitly as /ux-audit.


Why It Works

Most AI design feedback is bad for predictable reasons. This skill is built to avoid each one:

The usual problem How this skill avoids it
“Make it pop” vagueness Every finding is evaluated against a named heuristic and cited
Inconsistent results A fixed table of named checks means the same issue is flagged the same way every run
Hallucinated issues Evidence rules forbid claims about anything not visible in a screenshot; interaction-only qualities are listed as “not assessable”, never guessed
No prioritisation Findings are severity-rated and sorted; you see the criticals first
Not actionable Each finding carries a specific recommendation and an effort estimate

The core idea: the quality of the feedback depends on what you evaluate against. Generic “review this design” prompts produce generic output. Evaluating a journey against established heuristic frameworks, with citations, produces the kind of review you’d pay a consultant for.

Under the hood it runs four passes over your screens: a goal walk (where does the journey break for the stated user), a framework sweep (all 16 below), a named-checks pass (stable IDs so audits are comparable over time), and a journey-level pass (cross-screen consistency, memory load, Peak-End, and a Fogg behaviour-model read of the key conversion action).


The Frameworks

Findings are graded against 16 canonical frameworks, grouped by what they catch:

Category Frameworks
Classic usability Nielsen’s 10 Heuristics · Shneiderman’s 8 Golden Rules · Gerhardt-Powals’ Cognitive Principles · Bastien & Scapin’s Ergonomic Criteria
Behavioural psychology Hick’s Law · Fitts’s Law · Miller’s Law · Jakob’s Law · Peak-End Rule
Trust & persuasion Fogg Behaviour Model (B=MAP) · Cialdini’s Principles of Influence
Interaction design Gestalt Principles · Norman’s Design Principles · Tognazzini’s First Principles
Accessibility WCAG 2.1 (the subset checkable from a static image)
Content design 10 Content Design Heuristics

Each framework’s reference list and citation format lives in SKILL.md. Sources are linked at the bottom of every report.


Installation

Prerequisites

  • Claude Code or Codex
  • Python 3 with Pillow (for the annotation step): pip3 install --user pillow

1. Get the files

git clone https://github.com/EliaAlberti/ux-audit-skill.git
cd ux-audit-skill

2. Install into your tool

Claude Code:

mkdir -p ~/.claude/skills/ux-audit
cp -r SKILL.md scripts ~/.claude/skills/ux-audit/

Codex:

mkdir -p ~/.codex/skills/ux-audit
cp -r SKILL.md scripts ~/.codex/skills/ux-audit/

Prefer to edit in place? Symlink instead of copy: ln -s "$(pwd)" ~/.claude/skills/ux-audit

It’s a standard SKILL.md skill, so any Agent Skills manager that installs from a GitHub repo works too.

3. Restart

Skills are discovered at startup. Restart Claude Code or start a new Codex session, then ask for a UX audit.


Usage

Ask in plain language, or run /ux-audit in Claude Code. Point it at a folder of screenshots or attach them.

You: /ux-audit ./screenshots

Agent: I see 2 screenshots (sign-up, verify email). Before I start, two things:
       What's the product, and what is the user trying to do in this flow?

You: A SaaS app, a first-time visitor signing up for the free trial.

Agent: Got it. Platform, mobile web? And should I run the full framework
       sweep or focus on specific concerns?

You: Mobile web, full sweep.

Agent: Done. 0 critical, 3 major, 4 minor.
       Report + annotated screens saved to ./ux-audit-2026-01-15-saas-signup/

       Top 3 fixes:
       1. Field labels are placeholder-only, so they vanish on typing (WCAG 3.3.2)
       2. Password helper text fails contrast, the one rule users need is invisible (WCAG 1.4.3)
       3. The verify screen dead-ends, no resend / change-email / help if the link never arrives

       Want me to open issues for the three majors?

See a full example

A complete worked example, a two-screen journey (sign-up → verify email), lives in examples/:


How Severity Works

Findings are rated on Nielsen’s 0 to 4 scale, weighted by impact on the stated goal × how many users hit it × how often. Anchoring to the goal is why the skill asks what the user is trying to do before it starts.

Rating Label Meaning
🔴 4 Critical Blocks the goal, causes loss/harm, or legal/regulatory exposure; fix before release
🟠 3 Major Significant friction; many users struggle, some abandon
🟡 2 Minor Noticeable; users recover quickly
🔵 1 Cosmetic Polish; fix when convenient
🟢 ✓ Positive Works well; keep and replicate

Annotated screenshots use the same colour scale.


What It Can’t See

Honest limits. A static screenshot can’t show behaviour, so the skill never guesses at it, these are listed in every report under “not assessable” rather than invented:

  • Focus order and focus visibility
  • Keyboard navigation and screen-reader semantics
  • Motion, animation, transitions
  • Latency and loading states
  • Live interactive states not captured in the screenshots

For those, pair this with live/code-level accessibility testing.


FAQ


Contributing

Issues and PRs welcome, especially new named checks, framework refinements, and the annotation fallback. See CONTRIBUTING.md.


Credits

Created by Elia Alberti. The frameworks are the work of their original authors (Nielsen, Shneiderman, Gerhardt-Powals, Bastien & Scapin, Fogg, Cialdini, Norman, Tognazzini, the W3C, and others); each report links its sources.


License

MIT. See LICENSE.

View the full README on GitHub

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Install

npx skillfish add eliaalberti/ux-audit-skill
New to MCP? Start with the mcpskill.org guide →