agentmods.dev

PreToolUse

PreToolUse is a hook for Claude Code from akashsebastian333/peephole. Its token cost is not measured, scanned A, a copy of SessionStart, MIT.

A pre-tool-use hook that runs the peephole security script before selected coding-agent tools are used. Pre-tool-use means the check happens before actions such as writing files, editing code, running shell commands, or calling integrations.

In plain words
What is it for?
Use it to monitor or enforce peephole checks for file changes, terminal commands, searches, notebook edits, and integration tool calls.
Why use it?
It places a security check before potentially consequential agent actions, so a request can be reviewed before execution.

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 peephole plugin — 4 skills, 8 hooks shipped together

One of 8 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 7 are separate, each on its own page.

not rated 5repo 10d ago A scan tokens not measured copy · 81% MIT

Good fit Use it to monitor or enforce peephole checks for file changes, terminal commands, searches, notebook edits, and integration tool calls.

Compare 6 hooks from other repositories ↓
View source ↗ akashsebastian333/peephole
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 akashsebastian333/peephole
Claude Code
/plugin install peephole

Made for: Claude Code.

Or install peephole, the plugin that ships this one along with the rest of its 4 skills, 8 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/akashsebastian333/peephole/pre-tool-use/github.svg)](https://agentmods.dev/hooks/akashsebastian333/peephole/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/akashsebastian333/peephole/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/akashsebastian333/peephole/pre-tool-use/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for PreToolUse

Your own site · 80×15
<a href="https://agentmods.dev/hooks/akashsebastian333/peephole/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/akashsebastian333/peephole/pre-tool-use.svg" alt="Reviewed on agentmods" width="80" 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 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 9d 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.

hooks/hooks.json · 14 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Write|Edit|MultiEdit|NotebookEdit|Bash|write|search_replace|run_terminal_command|mcp__.*|.+__.*",
      "hooks": [
        {
          "type": "command",
          "command": "R=\"${CLAUDE_PLUGIN_ROOT:-$GROK_PLUGIN_ROOT}\"; E=\"\"; [ -r \"$R/bin/.peephole-exe\" ] && read -r E < \"$R/bin/.peephole-exe\"; case \"$E\" in \"$R\"/bin/*) if [ -x \"$E\" ]; then GOMAXPROCS=1 GOGC=off GODEBUG=asyncpreemptoff=1; export GOMAXPROCS GOGC GODEBUG; exec \"$E\" hook; fi ;; esac; exec sh \"$R/hooks/peephole.sh\" hook",
          "timeout": 10
        }
      ]
    }
  ]
}
Same file

What else hooks.json configures

This page is one entry in a file that holds 8. 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. 9d ago First seen · 14 lines scan A cccfbfbdac38

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository akashsebastian333/peephole (5 stars, last pushed 10d 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.

Securityai-agent-securityai-agent-skillsai-agentsai-agents-mcpai-codingai-security
Related

Other hooks, from other repositories

PostToolUse

Runs after a tool call finishes for Write and Edit tool calls, executing format_and_lint.sh. From supabase/supabase.

supabase/supabase · not measured

SessionStart

Runs when a session starts on startup, executing install_pkgs.sh. From supabase/supabase.

supabase/supabase · not measured

SessionStart

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

google-gemini/gemini-cli · not measured

PreToolUse

Runs before the agent uses a tool for Bash tool calls, running an inline shell check. From apache/superset.

apache/superset · not measured

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

PostToolUse

Runs after a tool call finishes for Write and Edit tool calls, executing format-ts.mjs via node. From prisma/orm.

prisma/orm · not measured