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.
npx skills add existential-birds/beagle --skill shadcn-uigit clone --depth 1 https://github.com/existential-birds/beagleWrote 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.
[](https://agentmods.dev/skills/existential-birds/beagle/shadcn-ui)<a href="https://agentmods.dev/skills/existential-birds/beagle/shadcn-ui"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/shadcn-ui/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.
<a href="https://agentmods.dev/skills/existential-birds/beagle/shadcn-ui"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/shadcn-ui.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00069 | $0.03307 |
| Opus 5.5 | $0.00028 | $0.01323 |
| Sonnet 5.5 | $0.00014 | $0.00661 |
| Haiku 4.5 | $0.00007 | $0.00331 |
Grade A, and why
shadcn-ui 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.
How it starts
The opening of the file, as written. The whole thing — 457 lines — stays where its author put it; the contents beside it link to each section on GitHub.
shadcn/ui Component Development
Contents
- CLI Commands - Installing and adding components
- Quick Reference - cn(), basic CVA pattern
- Component Anatomy - Props typing, asChild, data-slot
- Component Patterns - Compound components
- Styling Techniques - CVA variants, modern CSS selectors, accessibility states
- Decision Tables - When to use CVA, compound components, asChild, Context
- Common Patterns - Form elements, dialogs, sidebars
- Reference Files - Full implementations and advanced patterns
CLI Commands
Initialize shadcn/ui
npx shadcn@latest init
This creates a components.json configuration file and sets up:
- Tailwind CSS configuration
- CSS variables for theming
- cn() utility function
- Required dependencies
Add Components
# Add a single component
npx shadcn@latest add button
# Add multiple components
npx shadcn@latest add button card dialog
# Add all available components
npx shadcn@latest add --all
Important: The package name changed in 2024:
- Old (deprecated):
npx shadcn-ui@latest add - Current:
npx shadcn@latest add
Common Options
-y, --yes- Skip confirmation prompt-o, --overwrite- Overwrite existing files-c, --cwd <cwd>- Set working directory--src-dir- Use src directory structure
Gates (CLI and file changes)
Run these in order before init / add (skip only when you are not running the CLI—e.g. copying snippets from this skill):
- Working directory: Pass:
pwdandpackage.jsonat that path identify the app root that should receivecomponents/andcomponents.json(use-c <cwd>if the shell is elsewhere). - After
init: Pass:components.jsonexists at that app root (or the documented path for your monorepo layout). - Before
--overwrite: Pass: you can list which tracked files will be replaced, or version control shows the change is intentional and recoverable.
What ships with it
3 files 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.
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.
- 1mo ago First seen · 457 lines · 69 tokens per session scan A 6b31abc99f3f
shadcn-ui is a skill published in the GitHub repository existential-birds/beagle (82 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 69 tokens to every session and 3,307 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-16.
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