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.
git clone --depth 1 https://github.com/21st-dev/claude-code-pluginWrote 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/plugins/21st-dev/claude-code-plugin/21st)<a href="https://agentmods.dev/plugins/21st-dev/claude-code-plugin/21st"><img src="https://agentmods.dev/badge/plugins/21st-dev/claude-code-plugin/21st.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
21st 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 6d 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.
What it actually says
{
"name": "21st",
"description": "Find, generate, build, explore, review, and publish project-aware UI with seven verified 21st.dev skills plus the remote 21st MCP server.",
"version": "0.4.0",
"author": {
"name": "21st.dev",
"url": "https://21st.dev"
},
"homepage": "https://21st.dev",
"keywords": ["react", "shadcn", "ui", "components", "mcp", "frontend", "cli"],
"repository": "https://github.com/21st-dev/claude-code-plugin",
"license": "Apache-2.0"
}
What it installs
The manifest is a name and a version. 7 skills, 1 MCP server travel with it, and installing the plugin installs all of them — 1,055 tokens a session between them. Each is measured on its own page, and each can be installed alone.
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.
- 6d ago First seen · 14 lines scan A c0d3e9760baa
21st is a plugin published in the GitHub repository 21st-dev/claude-code-plugin (7 stars, last pushed 11d ago), licensed Apache-2.0. Its token cost is not measured: this kind of file is read by the harness, not the model. 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 2026-08-31.
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