21st-dev/skill

21st-ui-build

Build or substantially change production UI using the current project's design context, existing components, and grounded 21st inspiration. Use when implementing a page, section, component, responsive redesign, or visual polish in an existing web project. Trigger for requests such as "build this UI", "implement this screen", "make this page production-ready", or "use 21st to create the interface". Use 21st-ui-explore first when the visual direction is intentionally undecided, and 21st-ui-review…

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Installation

$ npx skills add 21st-dev/skill --skill 21st-ui-build

Summary

  • Build or substantially change production UI using the current project's design context, existing components, and grounded 21st inspiration.
  • Use when implementing a page, section, component, responsive redesign, or visual polish in an existing web project.
  • Trigger for requests such as "build this UI", "implement this screen", "make this page production-ready", or "use 21st to create the interface".
  • Use 21st-ui-explore first when the visual direction is intentionally undecided, and 21st-ui-review for critique-only work.

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More details

Agent compatibility

Declared targets from SKILL.md / docs. Unmarked agents are not listed — the skill may still install via the CLI.

Claude Code Not declared
Cursor Not declared
Codex Not declared
GitHub Copilot Not declared
Windsurf Not declared
Gemini CLI Not declared
Cline Not declared
OpenCode Not declared

Repository health

Stars 4
License LICENSE
Default branch main
Open issues 0
Status Active

Package contents

Files included with this skill beyond the listing page.

  • skill md SKILL.md 2,547 B
  • docs SUMMARY.md 2,472 B

History

  1. First recorded snapshot · 245 installs

SKILL.md

Build project-aware UI

Preserve the product's identity while using 21st supply to accelerate implementation.

Workflow

  1. Read .21st/design.json and .21st/DESIGN.md. If neither exists, run

21st init --design-context.

  1. Inspect the target route, its closest components, project instructions, and

existing tokens. Treat explicit project facts as stronger than generic taste.

  1. Search before generating:

``bash 21st search "<specific UI need>" --context auto ``

  1. Reuse installed project primitives first. Retrieve or install a 21st result

only when it reduces duplication or materially improves the result.

  1. If no result fits, generate project-aware alternatives:

``bash 21st generate "<goal and constraints>" --context auto --variants 3 ``

  1. Implement the selected direction in the project's real framework. Do not

paste sketch HTML when the project expects React components, tokens, or established APIs.

  1. Preserve responsive behavior, keyboard interaction, visible focus,

semantics, reduced motion, loading states, empty states, and error states.

  1. Run the project's checks and 21st review <changed paths>. Apply only safe,

deterministic fixes automatically.

Design rules

  • Prefer project tokens over new arbitrary values.
  • Prefer existing components over parallel lookalikes.
  • Preserve established density, radii, typography, iconography, and layout

rhythm unless the user explicitly requests a redesign.

  • Use real product copy and states when available.
  • Avoid decorative gradients, excessive cards, glass effects, huge headlines,

and animation unless supported by the project or requested.

  • Never claim a component, token, or capability exists without inspecting it.

Handoff

Report the direction used, reused 21st/project components, files changed, and verification performed. Record a durable visual choice in .21st/design.json under decisions when the user selects a new direction.