21st-ui-review
Review existing UI against the project's design context, accessibility expectations, responsive behavior, interaction quality, and high-confidence production rules. Use for UI audits, design QA, frontend review, accessibility review, consistency checks, or requests to find and safely fix visual defects. Trigger for requests such as "review this UI", "audit this page", "find design issues", "check responsiveness", or "fix obvious UX problems". Use 21st-ui-build when the request is primarily to create new UI.
How do I install this agent skill?
npx skills add https://github.com/21st-dev/skill --skill 21st-ui-reviewIs this agent skill safe to install?
- Gen Agent Trust Hubpass
The skill is functional for UI auditing but possesses an indirect prompt injection surface because it processes untrusted local project files and source code to drive its logic and tool execution.
- Socketpass
No alerts
- Snykpass
Risk: LOW · No issues
What does this agent skill do?
Review UI with evidence
Separate deterministic defects from subjective design recommendations.
Workflow
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Read
.21st/design.json, project instructions, and the relevant source. -
Run the deterministic review first:
21st review <path> 21st review <path> --json -
Inspect the actual component composition and runtime states. Validate claims against code rather than inferring behavior from names.
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Group findings into:
- deterministic defects;
- design-system drift;
- accessibility and interaction defects;
- responsive risks;
- subjective product/design recommendations.
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Prioritize by user impact and include exact file and line attribution.
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Use
21st review <path> --fixonly for deterministic, low-ambiguity fixes. Never silently redesign, change brand identity, or alter product behavior. -
Run relevant project tests after fixes and rerun review to prove resolution.
Review priorities
- semantic controls and accessible names;
- keyboard access, focus visibility, and dialog/menu behavior;
- image alternatives and meaningful labels;
- touch target size and disabled/loading states;
- responsive overflow and fixed-width assumptions;
- reduced-motion handling;
- hardcoded visual values that conflict with project tokens;
- duplicate primitives instead of existing components;
- inconsistent typography, radius, spacing, shadows, and icons;
- fake data, placeholder copy, or missing empty/error states.
Output
Lead with actionable findings ordered by severity. Keep subjective suggestions clearly labeled. If no issue is proven, say so and state what was inspected.
How can the creator link this skill?
Add the canonical catalog link to the repository README so users can inspect current installs and available audits. The publishing guide covers the complete discovery path.
<a href="https://skillzs.dev/skills/21st-dev/skill/21st-ui-review">View 21st-ui-review on skillZs</a>