21

21 is a hook for coding agents from rohitg00/awesome-claude-code-toolkit. Its token cost is not measured, scanned A, original, Apache-2.0.

Runs on the 21 event, executing pre-compact.js via node. From rohitg00/awesome-claude-code-toolkit.

Hook

Part of the claude-code-toolkit plugin — 25 hooks, 20 plugins shipped together

One of 25 entries in hooks.json — they are configured in one file and arrive together.

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.

agentmods
npx agentmods add hooks/rohitg00/awesome-claude-code-toolkit/21
Clone the repo
git clone --depth 1 https://github.com/rohitg00/awesome-claude-code-toolkit

Or install claude-code-toolkit, the plugin that ships this one along with the rest of its 25 hooks, 20 plugins.

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 21

README.md
[![agentmods](https://agentmods.dev/badge/hooks/rohitg00/awesome-claude-code-toolkit/21.svg)](https://agentmods.dev/hooks/rohitg00/awesome-claude-code-toolkit/21)
Your own site
<a href="https://agentmods.dev/hooks/rohitg00/awesome-claude-code-toolkit/21"><img src="https://agentmods.dev/badge/hooks/rohitg00/awesome-claude-code-toolkit/21.svg" alt="Measured on agentmods" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

21 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 yesterday.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

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.

hooks/hooks.json · 7 lines

What it actually says

{
  "21": {
    "type": "PreCompact",
    "description": "Save important context before compaction",
    "command": "node hooks/scripts/pre-compact.js"
  }
}
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. 4d ago First seen · 7 lines scan A de5a61c54486

Subscribe to this mod's changes

21 is a hook published in the GitHub repository rohitg00/awesome-claude-code-toolkit (2,585 stars, last pushed 3mo ago), licensed Apache-2.0. Its token cost is not measured: a hook is shell that never enters the context. 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 2026-08-30.