A set of checks that run before a coding agent uses tools such as reading, editing, writing files, or running shell commands. The checks cover secret paths, dangerous commands, shell quoting, pathless rewrites, and staged secrets.

Use it as a pre-tool safety layer for common file and shell operations in Claude Code.

It can stop risky tool calls before they alter files or run commands. It also checks that secrets are not exposed through paths or staged changes.

PreToolUse — Hook for Claude Code by AndrewDongminYoo: A set of checks that run before a coding…

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 AndrewDongminYoo/cc-agents-kit

Claude Code

/plugin install guard-hooks

Made for: Claude Code.

Or install guard-hooks, the plugin that ships this one along with the rest of its 2 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.

README.md

[![agentmods](https://agentmods.dev/badge/hooks/andrewdongminyoo/cc-agents-kit/pre-tool-use.svg)](https://agentmods.dev/hooks/andrewdongminyoo/cc-agents-kit/pre-tool-use)

Your own site

<a href="https://agentmods.dev/hooks/andrewdongminyoo/cc-agents-kit/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/andrewdongminyoo/cc-agents-kit/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 59% 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 5d 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

59% identical to SessionStart — 34 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.

plugins/guard-hooks/hooks/hooks.json · 39 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Read|Edit|Write|MultiEdit|NotebookEdit|Bash|Grep|Glob",
      "hooks": [
        {
          "type": "command",
          "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/secrets-path-guard.sh\"",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/dangerous-command-guard.sh\"",
          "timeout": 5
        },
        {
          "type": "command",
          "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/zsh-quoting-guard.sh\"",
          "timeout": 5
        },
        {
          "type": "command",
          "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/pathless-rewriter-guard.sh\"",
          "timeout": 5
        },
        {
          "type": "command",
          "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/staged-secret-guard.sh\"",
          "timeout": 10
        }
      ]
    }
  ]
}

Same file

What else `hooks.json` configures

This page is one entry in a file that holds 2. Installing the file brings all of them; each is measured and scanned on its own page.

Hook PostToolUse A not measured

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.

5d ago First seen · 39 lines scan A 15c0f7f8035d

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository AndrewDongminYoo/cc-agents-kit (1 stars, last pushed yesterday), licensed Apache-2.0. 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 59% identical to SessionStart, differing in 34 lines, and is treated as a copy.

Building agents Security claude-code claude-code-hooks claude-code-plugin developer-tools shell zsh

PreToolUse

Getting it into your agent

Wrote this? Show the measurements

Grade A, and why

Nothing flagged

This is a copy

What it actually says

What else `hooks.json` configures

What this file has done since we first saw it

Other hooks, from other repositories

SessionStart

SubagentStop

TeammateIdle

InstructionsLoaded

WorktreeCreate

TaskCreated

PreToolUse

Getting it into your agent

Wrote this? Show the measurements

Grade A, and why

Nothing flagged

This is a copy

What it actually says

What else hooks.json configures

What this file has done since we first saw it

Other hooks, from other repositories

SessionStart

SubagentStop

TeammateIdle

InstructionsLoaded

WorktreeCreate

TaskCreated

What else `hooks.json` configures