PreToolUse

PreToolUse is a hook for coding agents from volomydyr/design-engineer-plugin. Its token cost is not measured, scanned A, original, MIT.

Pre-tool hooks that run before selected agent actions such as shell commands, file edits, screenshots, and exiting a plan. The listed hooks check safety, test-first development, design grounding, and output paths.

In plain words
What is it for?
Applying automatic checks before Bash commands, writing or editing files, taking Playwright screenshots, and leaving plan mode.
Why use it?
They catch risky or non-compliant actions before they change files, run commands, or create screenshots.

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 design-engineer plugin — 35 skills, 11 commands, 10 agents, 6 hooks shipped together

One of 6 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 volomydyr/design-engineer-plugin
Claude Code
/plugin install design-engineer

Or install design-engineer, the plugin that ships this one along with the rest of its 35 skills, 11 commands, 10 agents, 6 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/volomydyr/design-engineer-plugin/pre-tool-use.svg)](https://agentmods.dev/hooks/volomydyr/design-engineer-plugin/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/volomydyr/design-engineer-plugin/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/volomydyr/design-engineer-plugin/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 · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-safety-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "Write|Edit|MultiEdit",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-tdd-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "Write|Edit|MultiEdit",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-design-grounding-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "Write|Edit|MultiEdit",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-deliverable-path-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "mcp__playwright__browser_take_screenshot",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-playwright-path-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "ExitPlanMode",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/de-pre-plan-dialogue-hook.js",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "get_screenshot",
      "hooks": [
        {
          "type": "prompt",
          "prompt": "A Figma screenshot tool is about to be called. Screenshots are supplementary – they must never be the primary source for implementation or design review.\n\nFor implementation: always use get_design_context first to get structured design data (code + metadata + screenshot together). Then ask clarifying questions about anything not visible in static designs before writing code.\n\nFor design review: always use get_design_context to compare structured design data against 

Read the full file on GitHub · 76 lines

Same file

What else hooks.json configures

This page is one entry in a file that holds 6. 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 · 76 lines scan A de53dda18126

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository volomydyr/design-engineer-plugin (19 stars, last pushed 1mo 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 2026-08-30.