21st-ui-explore

21st-ui-explore is a skill for Codex from 21st-dev/codex-plugin. It costs 98 tokens per session (570 once invoked), scanned A, a copy of 21st-ui-explore, Apache-2.0.

A workflow for exploring several different interface directions while keeping a project's existing design system, which is its shared visual rules, in mind. It uses 21st references and creates comparable previews before one direction is chosen.

In plain words
What is it for?
Creating UI concepts, redesign directions, visual variants, or previews for a current project, then recording the selected direction and removing abandoned variants.
Why use it?
It helps when the desired interface is unclear by turning a vague redesign idea into distinct options that can be compared.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Creating UI concepts, redesign directions, visual variants, or previews for a current project, then recording the selected direction and removing abandoned variants.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/21st-dev/codex-plugin/21st-ui-explore
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add 21st-dev/codex-plugin --skill 21st-ui-explore
Clone the repo
git clone --depth 1 https://github.com/21st-dev/codex-plugin

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for 21st-ui-explore

README.md
[![agentmods](https://agentmods.dev/badge/skills/21st-dev/codex-plugin/21st-ui-explore/github.svg)](https://agentmods.dev/skills/21st-dev/codex-plugin/21st-ui-explore)
Your own site
<a href="https://agentmods.dev/skills/21st-dev/codex-plugin/21st-ui-explore"><img src="https://agentmods.dev/badge/skills/21st-dev/codex-plugin/21st-ui-explore/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for 21st-ui-explore

Your own site · 80×15
<a href="https://agentmods.dev/skills/21st-dev/codex-plugin/21st-ui-explore"><img src="https://agentmods.dev/badge/skills/21st-dev/codex-plugin/21st-ui-explore.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 570 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00098 $0.00570
Opus 5.5 $0.00039 $0.00228
Sonnet 5.5 $0.00020 $0.00114
Haiku 4.5 $0.00010 $0.00057

Measured 1mo ago against content hash 1b94d8d00e7a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

21st-ui-explore scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to 21st-ui-explore — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/21st-ui-explore/SKILL.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Explore grounded UI directions

Create real choices without abandoning the project's visual identity.

Workflow

  1. Read .21st/design.json and the relevant product UI. If context is missing, run 21st init --design-context.

  2. Search 21st for multiple relevant references before generating:

    21st search "<interface and product context>" --context auto
    
  3. Define three named directions. Each direction must differ on at least two meaningful axes such as hierarchy, information density, navigation model, content emphasis, interaction pattern, or composition. Color-only variants do not count.

  4. Keep shared constraints fixed: real stack, tokens, brand assets, required content, accessibility, and responsive behavior.

  5. Create comparable previews. Check MCP get_usage.aiGenerationEnabled or run 21st usage and read the 21st AI generation line. CLI 1.17.1+ also supports 21st usage --json. Only when AI is explicitly enabled, use hosted generation with available AI credits:

    21st generate "<goal plus fixed constraints>" --context auto --variants 3
    

    Otherwise, implement the previews with your own coding agent, grounded in 21st search and 21st get (MCP: search and get_component). Do not call or suggest hosted generate or iterate_generation without AI access.

  6. Present the options together when the host supports a picker. Otherwise give each option a preview/deep link and a compact comparison.

  7. Recommend one direction with concrete tradeoffs, but let the user choose.

  8. After selection, remove abandoned local variants and record the decision in .21st/design.json.

Direction contract

For every direction provide:

  • a short, descriptive name;
  • the core idea and intended user effect;
  • the 21st/project references used;
  • what stays consistent with the project;
  • two or more meaningful differences;
  • accessibility or responsive risks;
  • the best-fit scenario.

Do not generate random style mutations. Every difference must support a product or usability hypothesis that a user can evaluate.

Read the full file on GitHub · 59 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago Changed · +7 lines 1b94d8d00e7a
  2. 1mo ago First seen · 52 lines · 98 tokens per session scan A 4482d001cfe8

Subscribe to this mod's changes

21st-ui-explore is a skill published in the GitHub repository 21st-dev/codex-plugin (10 stars, last pushed 10d ago), licensed Apache-2.0. It adds 98 tokens to every session and 570 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to 21st-ui-explore, differing in 0 lines, and is treated as a copy.

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