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PreToolUse

PreToolUse is a hook for coding agents from ArdurAI/ardur. Its token cost is not measured, scanned A, a copy of PreToolUse, MIT.

A pre-tool hook is an automatic command that runs before the agent uses a tool. It runs a shell check before each matching tool call.

In plain words
What is it for?
It is for running a predefined shell script before tool calls.
Why use it?
It provides a consistent checkpoint before tools run, without requiring the agent to perform the same check manually.

Hook

Part of the ardur-claude-code-hook plugin — 5 hooks shipped together

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

not rated 2 3d ago A scan tokens not measured copy · 86% MIT
View the source file ArdurAI/ardur
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/ardurai/ardur/pre-tool-use
Clone the repo
git clone --depth 1 https://github.com/ArdurAI/ardur

Or install ardur-claude-code-hook, the plugin that ships this one along with the rest of its 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/ardurai/ardur/pre-tool-use.svg)](https://agentmods.dev/hooks/ardurai/ardur/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/ardurai/ardur/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/ardurai/ardur/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 86% copy Near-identical to another mod 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 3d 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.

Origin

This is a copy

86% identical to PreToolUse — 25 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/claude-code/hooks/hooks.json · 13 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": ".*",
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/hooks/pre_tool_use"
        }
      ]
    }
  ]
}
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. 3d ago First seen · 13 lines scan A 6a9dc2085367

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository ArdurAI/ardur (2 stars, last pushed 3d 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. It is 86% identical to PreToolUse, differing in 25 lines, and is treated as a copy.

AI Safetyagent-governanceai-agentsai-governanceopen-sourceruntime-security
Related

Other hooks, from other repositories

UserPromptSubmit

Runs when you submit a prompt, before the agent sees it, executing consent_gate_grant.mjs via node. From friedbotstudio/baseline.

friedbotstudio/baseline · not measured

PreToolUse

Runs before the agent uses a tool for Bash, WebFetch, WebSearch, Write, Edit, NotebookEdit, Task, SendMessage and mcp__.* tool calls, executing run.sh via sh. From vaaraio/vaara.

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PostToolUse

Runs after a tool call finishes for Bash, WebFetch, WebSearch, Write, Edit, NotebookEdit, Task, SendMessage and mcp__.* tool calls, executing run.sh via sh. From vaaraio/vaara.

vaaraio/vaara · not measured

SessionStart

Runs when a session starts, executing run.sh via sh. From vaaraio/vaara.

vaaraio/vaara · not measured

PreToolUse

Runs before the agent uses a tool for AskUserQuestion, Bash, Write, Edit, MultiEdit, NotebookEdit and Write tool calls, executing notify.mjs, destructive_cmd_guard.mjs, state_write_guard.mjs, git_commit_guard.mjs, gitignore_leak_guard.mjs, process_lifecycle_guard.mjs, setup_guard.mjs, env_guard.mjs…

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PreToolUse

Runs before the agent uses a tool, executing guard-hook.js and collector-hook.js via node (2 commands). From core0-io/nio.

core0-io/nio · not measured