A pre-tool hook that runs a protection script before write, edit, notebook, or shell actions. A hook is an automatic check that runs before another action.

It helps enforce safeguards around graph-engineering files before an agent writes, edits, or runs shell commands.

It can protect graph-related files from changes made by those tools.

PreToolUse — Hook by sciencemj

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/sciencemj/graph-engineering/pre-tool-use

Clone the repo

git clone --depth 1 https://github.com/sciencemj/graph-engineering

Or install graph-engineering, the plugin that ships this one along with the rest of its 1 skill, 5 commands, 1 hook, 1 MCP server.

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 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 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.

hooks/hooks.json · 13 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Write|Edit|NotebookEdit|Bash",
      "hooks": [
        {
          "type": "command",
          "command": "bun ${CLAUDE_PLUGIN_ROOT}/hooks/protect-graph-files.ts"
        }
      ]
    }
  ]
}

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.

2d ago First seen · 13 lines scan A 93be26cbd37c

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository sciencemj/graph-engineering (0 stars, last pushed 1mo 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

bun claude-code claude-code-plugin dag mcp

PreToolUse

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

Stop

SessionStart

SessionStart

SessionStart

SessionStart

PostToolUseFailure