PreToolUse

PreToolUse is a hook for coding agents from yannmenec/inspectrum. Its token cost is not measured, scanned A, original, MIT.

A pre-tool hook that runs a script before the agent exits a planning step. A hook is an automatic action triggered by a specified event.

In plain words
What is it for?
Use it in agent configurations where plan-exit actions need to trigger plan-gate-shim.sh before continuing.
Why use it?
It adds a check before a plan is accepted or left, helping enforce a project's planning gate. The input does not describe what the script checks.

Hook

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 inspectrum plugin — 1 skill, 2 commands, 1 hook, 1 MCP server shipped 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 yannmenec/inspectrum
Claude Code
/plugin install inspectrum

Or install inspectrum, the plugin that ships this one along with the rest of its 1 skill, 2 commands, 1 hook, 1 MCP server.

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/yannmenec/inspectrum/pre-tool-use.svg)](https://agentmods.dev/hooks/yannmenec/inspectrum/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/yannmenec/inspectrum/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/yannmenec/inspectrum/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 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.

hooks/hooks.json · 14 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "ExitPlanMode",
      "hooks": [
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/scripts/plan-gate-shim.sh",
          "timeout": 600
        }
      ]
    }
  ]
}
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 · 14 lines scan A 85b78572649b

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository yannmenec/inspectrum (2 stars, last pushed 24d 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.