PreToolUse

A pre-tool hook that runs a command before the agent uses any tool. Hooks are automatic actions attached to an agent workflow.

In plain words
What is it for?
Use it to run the specified agent-context-graph command before every tool call in Claude Code.
Why use it?
It records or updates context before tool use through the listed context-graph connectors, helping preserve information about skills, actions, and sessions.

Hook

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add hooks/memgraph/ai-toolkit/pre-tool-use
Clone the repo
git clone --depth 1 https://github.com/memgraph/ai-toolkit
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 81% 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 2d 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

81% identical to SessionStart — 3 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.

context-graph/plugins/agent-context-graph-claude/hooks/hooks.json · 14 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "*",
      "hooks": [
        {
          "type": "command",
          "command": "agent-context-graph hook run claude-code --connector skills-graph --connector actions-graph --connector sessions-graph",
          "timeout": 30
        }
      ]
    }
  ]
}
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. 2d ago First seen · 14 lines scan A ee8204482850

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository memgraph/ai-toolkit (112 stars, last pushed 4d 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 81% identical to SessionStart, differing in 3 lines, and is treated as a copy.