PreToolUse

PreToolUse is a hook for Claude Code from swt-labs/vibe-better-with-claude-code-vbw. Its token cost is not measured, scanned A, a copy of PostToolUse, MIT.

A pre-tool hook that runs a shell script before the agent uses selected tools, such as Bash, file editing, task management, or other agents.

In plain words
What is it for?
Use it to run the project's pre-action checks before shell commands, task operations, or file and agent changes.
Why use it?
It provides a checkpoint before those actions happen, using the configured hook script.

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 vbw plugin — 11 skills, 26 commands, 7 agents, 11 hooks shipped together

One of 11 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 10 are separate, each on its own page.

Good fit Use it to run the project's pre-action checks before shell commands, task operations, or file and agent changes.

Compare 6 hooks from other repositories ↓
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 swt-labs/vibe-better-with-claude-code-vbw
Claude Code
/plugin install vbw

Made for: Claude Code.

Or install vbw, the plugin that ships this one along with the rest of its 11 skills, 26 commands, 7 agents, 11 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/swt-labs/vibe-better-with-claude-code-vbw/pre-tool-use.svg)](https://agentmods.dev/hooks/swt-labs/vibe-better-with-claude-code-vbw/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/swt-labs/vibe-better-with-claude-code-vbw/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/swt-labs/vibe-better-with-claude-code-vbw/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. A grade says what 26 rules found in the file — not that it is safe.
Origin 97% 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 8d 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

97% identical to PostToolUse — 49 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.

hooks/hooks.json · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "bash -c 'w=$(ls -1 \"${CLAUDE_CONFIG_DIR:-$HOME/.claude}\"/plugins/cache/vbw-marketplace/vbw/*/scripts/hook-wrapper.sh 2>/dev/null | (sort -V 2>/dev/null || sort -t. -k1,1n -k2,2n -k3,3n) | tail -1); [ ! -f \"$w\" ] && w=\"${CLAUDE_PLUGIN_ROOT:+$CLAUDE_PLUGIN_ROOT/scripts/hook-wrapper.sh}\"; [ ! -f \"$w\" ] && for f in /tmp/.vbw-plugin-root-link-*/scripts/hook-wrapper.sh; do [ -f \"$f\" ] && w=\"$f\" && break; done; [ ! -f \"$w\" ] && { D=$(ps axww -o args= 2>/dev/null | grep -v grep | grep -oE -- \"--plugin-dir [^ ]+\" | head -1); D=\"${D#--plugin-dir }\"; [ -n \"$D\" ] && w=\"$D/scripts/hook-wrapper.sh\"; }; [ -f \"$w\" ] && exec bash \"$w\" bash-guard.sh; exit 0'",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "Agent|TaskCreate",
      "hooks": [
        {
          "type": "command",
          "command": "bash -c 'w=$(ls -1 \"${CLAUDE_CONFIG_DIR:-$HOME/.claude}\"/plugins/cache/vbw-marketplace/vbw/*/scripts/hook-wrapper.sh 2>/dev/null | (sort -V 2>/dev/null || sort -t. -k1,1n -k2,2n -k3,3n) | tail -1); [ ! -f \"$w\" ] && w=\"${CLAUDE_PLUGIN_ROOT:+$CLAUDE_PLUGIN_ROOT/scripts/hook-wrapper.sh}\"; [ ! -f \"$w\" ] && for f in /tmp/.vbw-plugin-root-link-*/scripts/hook-wrapper.sh; do [ -f \"$f\" ] && w=\"$f\" && break; done; [ ! -f \"$w\" ] && { D=$(ps axww -o args= 2>/dev/null | grep -v grep | grep -oE -- \"--plugin-dir [^ ]+\" | head -1); D=\"${D#--plugin-dir }\"; [ -n \"$D\" ] && w=\"$D/scripts/hook-wrapper.sh\"; }; [ -f \"$w\" ] && exec bash \"$w\" agent-spawn-guard.sh; exit 0'",
          "timeout": 5
        },
        {
          "type": "command",
          "command": "bash -c 'w=$(ls -1 \"${CLAUDE_CONFIG_DIR:-$HOME/.claude}\"/plugins/cache/vbw-marketplace/vbw/*/scripts/hook-wrapper.sh 2>/dev/null | (sort -V 2>/dev/null || sort -t. -k1,1n -k2,2n -k3,3n) | tail -1); [ ! -f \"$w\" ] && w=\"${CLAUDE_PLUGIN_ROOT:+$

Read the full file on GitHub · 79 lines

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. 8d ago First seen · 79 lines scan A 7575f959bdfa

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository swt-labs/vibe-better-with-claude-code-vbw (79 stars, last pushed 2mo 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 97% identical to PostToolUse, differing in 49 lines, and is treated as a copy.