PreToolUse

PreToolUse is a hook for Claude Code from AlexShchuka/neuro-matrix. Its token cost is not measured, scanned A, a copy of SessionStart, MIT.

A set of checks that runs before selected agent tools, such as shell commands, file edits, and other agent calls. The listed checks detect cycles, guard risky operations, require verification, critique commands, and check whether a skill was consulted.

In plain words
What is it for?
Use it to run pre-action checks for Bash, editing, notebook changes, and agent calls through the configured hook commands.
Why use it?
It adds automated review gates before certain actions take place. This can catch unsafe, unverified, repetitive, or procedurally incomplete work early.

Hook for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: names the NotebookEdit 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 neuro-matrix plugin — 6 skills, 5 agents, 4 hooks shipped together

One of 4 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 3 are separate, each on its own page.

Good fit Use it to run pre-action checks for Bash, editing, notebook changes, and agent calls through the configured hook commands.

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 AlexShchuka/neuro-matrix
Claude Code
/plugin install neuro-matrix

Made for: Claude Code.

Or install neuro-matrix, the plugin that ships this one along with the rest of its 6 skills, 5 agents, 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/alexshchuka/neuro-matrix/pre-tool-use.svg)](https://agentmods.dev/hooks/alexshchuka/neuro-matrix/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/alexshchuka/neuro-matrix/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/alexshchuka/neuro-matrix/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 66% 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

66% 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.

hooks/hooks.json · 39 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash|Edit|Write|MultiEdit|NotebookEdit",
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/cycle-detector.sh"
        }
      ]
    },
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/redline-guard.sh"
        },
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/verification-gate.sh"
        },
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/auto-critic.sh"
        }
      ]
    },
    {
      "matcher": "Agent",
      "hooks": [
        {
          "type": "command",
          "command": "${CLAUDE_PLUGIN_ROOT}/scripts/skill-consult-check.sh"
        }
      ]
    }
  ]
}
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. 8d ago First seen · 39 lines scan A 061b3005eda5

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository AlexShchuka/neuro-matrix (3 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 66% identical to SessionStart, differing in 34 lines, and is treated as a copy.