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.
- Skill ID
- 21st-dev/skill/21st-ui-review
- Publisher
- 21st-dev
- Repository
- skill
- Installs
- 0
- Files
- 2
- Synced
- Sep 23, 2026
Open any RiverX project, open the Skills panel in the chat, and search for this identifier. The files are fetched from the source repository at install time.
21st-dev/skill/21st-ui-reviewInstalls these files- SKILL.md
- agents/openai.yaml
What this skill tells the agent
Review UI with evidence
Separate deterministic defects from subjective design recommendations.
Workflow
- 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.
- Group findings into:
- deterministic defects;
- design-system drift;
- accessibility and interaction defects;
- responsive risks;
- subjective product/design recommendations.
- Prioritize by user impact and include exact file and line attribution.
- 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.
More from 21st-dev
Use this skill in a project
Open any RiverX project, search the Skills panel for 21st-dev/skill/21st-ui-review, and install it in one click.