agentmods.dev

janus-datalog: Hook for Claude Code

.claude/settings.json

PreToolUse is a hook for Claude Code from wbrown/janus-datalog. Its token cost is not measured, scanned A, a copy of SessionStart, Apache-2.0.

Automated checks that run before Bash, edit, write, or update actions. They validate commands, review proposed file changes, and check the reasoning behind them.

In plain words
What is it for?
Use them to validate shell commands, inspect edits, and perform reasoning checks before tools change files or run commands.
Why use it?
They catch unsafe commands and questionable changes before the agent applies them to the project.

Hook for Claude Code

Written for Claude Code: $CLAUDE_PROJECT_DIR variable.

This is wbrown/janus-datalog's own configuration. It tells Claude Code how to work on janus-datalog itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything janus-datalog configures →

One of 3 entries in settings.json upstream. Installing this one merges just its entry into your config; the other 2 are separate, each on its own page.

not rated 54repo +1 today A scan tokens not measured copy · 47% Apache-2.0
View source ↗ wbrown/janus-datalog
Reuse

Borrowing it

Nothing to install: this file belongs to wbrown/janus-datalog. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/wbrown/janus-datalog/main/.claude/settings.json
Clone the repo
git clone --depth 1 https://github.com/wbrown/janus-datalog

Made for: Claude Code.

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/wbrown/janus-datalog/pre-tool-use/github.svg)](https://agentmods.dev/hooks/wbrown/janus-datalog/pre-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/wbrown/janus-datalog/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/wbrown/janus-datalog/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/wbrown/janus-datalog/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/wbrown/janus-datalog/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 47% 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 1mo 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

47% identical to SessionStart — 23 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.

.claude/settings.json · 28 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/validate-bash.sh"
        }
      ]
    },
    {
      "matcher": "Edit|Write|Update",
      "hooks": [
        {
          "type": "command",
          "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/review-edit.sh",
          "timeout": 120
        },
        {
          "type": "command",
          "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/review-reasoning.sh",
          "timeout": 300
        }
      ]
    }
  ]
}
Same file

What else settings.json configures

This page is one entry in a file that holds 3. 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. 1mo ago First seen · 28 lines scan A cb6b1c16a844

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository wbrown/janus-datalog (54 stars, last pushed today), licensed Apache-2.0. 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 47% identical to SessionStart, differing in 23 lines, and is treated as a copy.

Security
Related

Other hooks, from other repositories

SessionStart

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

supabase/supabase · not measured

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, 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 Bash tool calls, executing hooks.sh via sh (3 commands). From anthropics/claude-plugins-official.

anthropics/claude-plugins-official · not measured