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PreToolUse

PreToolUse is a hook for Claude Code from Jebel-Quant/rhiza-claude. Its token cost is not measured, scanned A, original, MIT.

A safety check that runs before the agent executes Bash commands, which are terminal commands on Unix-like systems.

In plain words
What is it for?
Run a Python command guard before Bash tool calls.
Why use it?
It checks commands against the project’s configured safety rules before they run.

Hook for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the rhiza plugin — 10 skills, 1 hook shipped together

not rated 4repo yesterday A scan tokens not measured original MIT

Good fit Run a Python command guard before Bash tool calls.

Compare 6 hooks from other repositories ↓
View source ↗ Jebel-Quant/rhiza-claude jebel-quant.github.io
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add Jebel-Quant/rhiza-claude
Claude Code
/plugin install rhiza

Made for: Claude Code.

Or install rhiza, the plugin that ships this one along with the rest of its 10 skills, 1 hook.

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 PreToolUse

README.md
[![agentmods](https://agentmods.dev/badge/hooks/jebel-quant/rhiza-claude/pre-tool-use.svg)](https://agentmods.dev/hooks/jebel-quant/rhiza-claude/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/jebel-quant/rhiza-claude/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/jebel-quant/rhiza-claude/pre-tool-use.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. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

PreToolUse 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 7d ago.

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.

plugin/hooks/hooks.json · 15 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "python3 \"${CLAUDE_PLUGIN_ROOT}/scripts/hook_bash_guard.py\"",
          "timeout": 10,
          "statusMessage": "Checking the command against the rhiza guards"
        }
      ]
    }
  ]
}
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. 7d ago First seen · 15 lines scan A 02c34f40ec6d

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository Jebel-Quant/rhiza-claude (4 stars, last pushed yesterday), licensed MIT. 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 2026-08-31.

Claude Codeclaudeclaude-code-pluginclirhiza
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PreToolUse

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