agentmods.dev

PreToolUse

PreToolUse is a hook for Claude Code from es6kr/skills. Its token cost is not measured, scanned A, original, MIT.

Checks that run before the agent uses tools such as Bash, file editing, skills, workflows, or other agents. The listed scripts inspect commands and block several risky or disallowed actions.

In plain words
What is it for?
Use it to review Bash commands, block compound commands, protect production branches, prevent malformed workflows, and enforce project rules before tool use.
Why use it?
They add guardrails before actions happen, helping prevent unsafe shell commands, repeated triggers, unsuitable branch operations, and other workflow violations.

Hook for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: names the AskUserQuestion tool.

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 es6kr plugin — 36 skills, 5 hooks shipped together

One of 5 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 4 are separate, each on its own page.

not rated 2repo changed yesterday A scan tokens not measured original MIT

Good fit Use it to review Bash commands, block compound commands, protect production branches, prevent malformed workflows, and enforce project rules before tool use.

Compare 6 hooks from other repositories ↓
View source ↗ es6kr/skills
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 es6kr/skills
Claude Code
/plugin install es6kr

Made for: Claude Code.

Or install es6kr, the plugin that ships this one along with the rest of its 36 skills, 5 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/es6kr/skills/pre-tool-use/github.svg)](https://agentmods.dev/hooks/es6kr/skills/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/es6kr/skills/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/es6kr/skills/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/es6kr/skills/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/es6kr/skills/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 yesterday.

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 · 281 lines

How it starts

The opening of the file, as written. The whole thing — 281 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "PreToolUse": [
    {
      "matcher": "*",
      "hooks": [
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/check-excessive-ci-polling.sh"
        }
      ]
    },
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/bash-guard.py"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-compound-commands.sh"
        },
        {
          "type": "command",
          "command": "python3 ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-copilot-rate-limit.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-squash-subject-without-pr.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-bot-re-trigger.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-long-silent-watcher.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-prod-branch-autonomous-ops.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/hook-kit/resources/block-delegation-in-github-body.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/consolidate/resources/block-noncompliant-review-comment.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/consolidate/resources/block-review-post-without-receiving-code-review.sh"
        },
        {
          "type": "command",
          "command": "bash ${CLAUDE_PLUGIN_ROOT}/skills/consolidate/resources/block-summary-fabric

Read the full file on GitHub · 281 lines

Same file

What else hooks.json configures

This page is one entry in a file that holds 5. 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. yesterday Changed · +5 lines 4f72b74568a2
  2. 4d ago Changed · +4 lines 114565af924c
  3. 10d ago Changed · +8 lines da39f19f31df
  4. 18d ago Changed · +4 lines 9ad5e8e97eed
  5. 24d ago Changed · +4 lines 7fc6dbddedc7
  6. 26d ago Changed · -7 lines 1c5fb1d8fdc2
  7. 1mo ago Changed · +4 lines c54b6eaa0bbb
  8. 1mo ago Changed · +15 lines 0b64a0b6b805
  9. 1mo ago Changed 30617d583763
  10. 1mo ago First seen · 244 lines scan A bd92f7032dff

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository es6kr/skills (2 stars, last pushed yesterday), 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.

Related

Other hooks, from other repositories

PreToolUse

Runs before the agent uses a tool for Bash tool calls, running an inline shell check. From apache/superset.

apache/superset · not measured

PreToolUse

Runs before the agent uses a tool, executing pre-write.sh and pre-bash.sh (2 commands). From anthropics/claude-cookbooks.

anthropics/claude-cookbooks · not measured

PostToolUse

Runs after a tool call finishes for Bash tool calls, executing hooks.sh via sh (3 commands). From anthropics/claude-plugins-official.

anthropics/claude-plugins-official · not measured

PreCompact

Runs before the context is compacted for manual and auto tool calls, executing hook-handler.cjs via node (4 commands). From ruvnet/RuView.

ruvnet/RuView · not measured

PreToolUse

Runs before the agent uses a tool for Bash tool calls, running node -e ". From heygen-com/hyperframes.

heygen-com/hyperframes · not measured

SessionStart

Runs when a session starts, executing hook-handler.cjs and auto-memory-hook.mjs via node (2 commands). From ruvnet/RuView.

ruvnet/RuView · not measured