PreToolUse

PreToolUse is a hook for Claude Code from huangruiteng/loopx. Its token cost is not measured, scanned A, original, Apache-2.0.

A pre-action hook that runs a Python policy script before any agent tool is used. It applies to every tool call in the project.

In plain words
What is it for?
Checking or controlling all agent tool calls through the named Python policy script. The specific checks depend on that script.
Why use it?
It provides a place to enforce a project rule before tools run, but the input does not describe the rule itself.

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 loopx-goal-mode plugin — 1 command, 1 hook shipped together

Good fit Checking or controlling all agent tool calls through the named Python policy script. The specific checks depend on that script.

Compare 6 hooks from other repositories ↓
About the project

LoopX is a provider-neutral control plane that gives long-running AI-agent work persistent state, decisions, governance, recovery, and handoffs across different agent harnesses. It is for managing and reviewing durable work performed by Codex, Claude Code, Cursor, dsh, or custom agent systems.

huangruiteng/loopx · 6,356 stars · on GitHub · huangruiteng.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 huangruiteng/loopx
Claude Code
/plugin install loopx-goal-mode

Made for: Claude Code.

Or install loopx-goal-mode, the plugin that ships this one along with the rest of its 1 command, 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/huangruiteng/loopx/pre-tool-use/github.svg)](https://agentmods.dev/hooks/huangruiteng/loopx/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/huangruiteng/loopx/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/huangruiteng/loopx/pre-tool-use/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for PreToolUse

Your own site · 80×15
<a href="https://agentmods.dev/hooks/huangruiteng/loopx/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/huangruiteng/loopx/pre-tool-use.svg" alt="Reviewed on agentmods" width="80" 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 1mo 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.

loopx/claude_goal_mode/hooks/hooks.json · 14 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "*",
      "hooks": [
        {
          "type": "command",
          "command": "python3 \"${CLAUDE_PLUGIN_ROOT}/hooks/goal_policy.py\"",
          "timeout": 10
        }
      ]
    }
  ]
}
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. 1mo ago First seen · 14 lines scan A d9170d2202bc

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository huangruiteng/loopx (6,356 stars, last pushed today), 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.