PreToolUse

PreToolUse is a hook for coding agents from ao92265/claude-code-playbook. Its token cost is not measured, scanned A, original, MIT.

A set of automatic checks that run before shell commands or file edits in an agent workflow.

In plain words
What is it for?
Use it to guard Bash, Edit, and Write operations with checks for debug statements, secrets, unsafe commands, and restricted files.
Why use it?
It helps catch debug code, exposed environment secrets, dangerous commands, or edits to protected paths before they take effect.

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 playbook plugin — 49 skills, 4 hooks shipped together

One of 4 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 ao92265/claude-code-playbook
Claude Code
/plugin install playbook

Or install playbook, the plugin that ships this one along with the rest of its 49 skills, 4 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/ao92265/claude-code-playbook/pre-tool-use.svg)](https://agentmods.dev/hooks/ao92265/claude-code-playbook/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/ao92265/claude-code-playbook/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/ao92265/claude-code-playbook/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 4d 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 · 38 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/hooks/pre-commit-guard.sh",
          "timeout": 10,
          "statusMessage": "Checking for debug statements..."
        },
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/hooks/env-guard.sh",
          "timeout": 10,
          "statusMessage": "Checking for secrets..."
        },
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/hooks/firewall.sh",
          "timeout": 5,
          "statusMessage": "Checking for dangerous commands..."
        }
      ]
    },
    {
      "matcher": "Edit|Write",
      "hooks": [
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/hooks/protect-paths.sh",
          "timeout": 5,
          "statusMessage": "Checking for protected files..."
        }
      ]
    }
  ]
}
Same file

What else hooks.json configures

This page is one entry in a file that holds 4. 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. 4d ago First seen · 38 lines scan A 0bdf688cbb41

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository ao92265/claude-code-playbook (10 stars, last pushed 18d 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.