arai: Hook for Claude Code

.claude/settings.json

PostToolUse is a hook for Claude Code from taniwhaai/arai. Its token cost is not measured, scanned A, a copy of CwdChanged, Apache-2.0.

A post-tool hook that runs the command arai guardrails --match-stdin after another tool finishes. A hook is an automatic action attached to an event.

In plain words
What is it for?
Use it to run arai guardrail checks on the output of every completed tool call.
Why use it?
It applies the project’s guardrails after tool activity without requiring a person to run the check manually.

Hook for Claude Code

Written for Claude Code: PostToolUse hook event.

This is taniwhaai/arai's own configuration. It tells Claude Code how to work on arai 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 arai configures →

One of 9 entries in settings.json upstream. Installing this one merges just its entry into your config; the other 8 are separate, each on its own page.

Reuse

Borrowing it

Nothing to install: this file belongs to taniwhaai/arai. 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/taniwhaai/arai/main/.claude/settings.json
Clone the repo
git clone --depth 1 https://github.com/taniwhaai/arai

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 PostToolUse

README.md
[![agentmods](https://agentmods.dev/badge/hooks/taniwhaai/arai/post-tool-use.svg)](https://agentmods.dev/hooks/taniwhaai/arai/post-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/taniwhaai/arai/post-tool-use"><img src="https://agentmods.dev/badge/hooks/taniwhaai/arai/post-tool-use.svg" alt="Measured on agentmods" 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 88% copy Near-identical to another mod in the catalogue.
Security

Grade A, and why

PostToolUse 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 7d 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

88% identical to CwdChanged — 2 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 · 14 lines

What it actually says

{
  "PostToolUse": [
    {
      "hooks": [
        {
          "command": "arai guardrails --match-stdin",
          "timeout": 3,
          "type": "command"
        }
      ],
      "matcher": ""
    }
  ]
}
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. 7d ago First seen · 14 lines scan A 8bd476e85f20

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository taniwhaai/arai (7 stars, last pushed 25d ago), 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 88% identical to CwdChanged, differing in 2 lines, and is treated as a copy.