PreToolUse

PreToolUse is a hook for Claude Code from Crypto-star/mahoraga. Its token cost is not measured, scanned A, original, MIT.

Hooks that run a shell script before the agent uses Bash, Write, Edit, WebFetch, or WebSearch tools.

In plain words
What is it for?
They are for applying pre-action checks to command execution, file changes, web fetching, and web searches.
Why use it?
They create a checkpoint before potentially important actions, so the script can inspect, approve, record, or prepare those calls.

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 mahoraga plugin — 2 commands, 5 hooks shipped together

One of 5 entries in hooks.json — they are configured in one file and arrive together.

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 Crypto-star/mahoraga
Claude Code
/plugin install mahoraga

Made for: Claude Code.

Or install mahoraga, the plugin that ships this one along with the rest of its 2 commands, 5 hooks.

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/crypto-star/mahoraga/pre-tool-use.svg)](https://agentmods.dev/hooks/crypto-star/mahoraga/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/crypto-star/mahoraga/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/crypto-star/mahoraga/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. Scan, not verified.
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 5d 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.

hooks/hooks.json · 13 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash|Write|Edit|WebFetch|WebSearch",
      "hooks": [
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/scripts/pre-tool-handler.sh"
        }
      ]
    }
  ]
}
Same file

What else hooks.json configures

This page is one entry in a file that holds 5. Installing the file brings all of them; each is measured and scanned on its own page.

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. 5d ago First seen · 13 lines scan A 9d84cf9f92d8

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository Crypto-star/mahoraga (7 stars, last pushed 7mo ago), 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.