agentmods.dev

PreToolUse

A pre-action hook that runs a guard script before the agent uses Read, Glob, Grep, or Bash. These are tools for reading files, finding files, searching text, and running shell commands.

In plain words
What is it for?
Use it to guard file reads, file searches, text searches, and Bash commands through the configured guard script.
Why use it?
It adds a check before common file and shell operations, so those actions can be screened before they run.

Hook

11 13d ago A scan tokens not measured original MIT
View the source file agentic-dev3o/devx-plugins
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/agentic-dev3o/devx-plugins/pre-tool-use
Clone the repo
git clone --depth 1 https://github.com/agentic-dev3o/devx-plugins
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 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.

plugins/secrets-guard/hooks/hooks.json · 13 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Read|Glob|Grep|Bash",
      "hooks": [
        {
          "type": "command",
          "command": "\"${CLAUDE_PLUGIN_ROOT}\"/hooks/guard.sh"
        }
      ]
    }
  ]
}
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 First seen · 13 lines scan A 4a8acda66b2b

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository agentic-dev3o/devx-plugins (11 stars, last pushed 13d 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 2026-08-30.

Research
Related

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SessionStart

Runs when a session starts, executing on-start.js via node. From google-gemini/gemini-cli.

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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

SessionStart

Runs when a session starts, executing session-start.sh. From anthropics/claude-cookbooks.

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