FileChanged

FileChanged is a hook for Claude Code from taniwhaai/arai. Its token cost is not measured, scanned A, original, Apache-2.0.

A file-change hook that runs a guardrail command when selected coding-agent instruction files are modified.

In plain words
What is it for?
Running `arai guardrails --match-stdin` when `CLAUDE.md`, `.cursorrules`, `.windsurfrules`, or `copilot-instructions.md` changes.
Why use it?
It checks changes to agent rules early, helping prevent unsafe or unwanted instruction updates.

Hook for Claude Code

One of 9 entries in settings.json — they are configured in one file and arrive together.

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/taniwhaai/arai/file-changed
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 FileChanged

README.md
[![agentmods](https://agentmods.dev/badge/hooks/taniwhaai/arai/file-changed.svg)](https://agentmods.dev/hooks/taniwhaai/arai/file-changed)
Your own site
<a href="https://agentmods.dev/hooks/taniwhaai/arai/file-changed"><img src="https://agentmods.dev/badge/hooks/taniwhaai/arai/file-changed.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. Scan, not verified.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

FileChanged 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 4d 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.

.claude/settings.json · 14 lines

What it actually says

{
  "FileChanged": [
    {
      "hooks": [
        {
          "command": "arai guardrails --match-stdin",
          "timeout": 3,
          "type": "command"
        }
      ],
      "matcher": "CLAUDE.md|.cursorrules|.windsurfrules|copilot-instructions.md"
    }
  ]
}
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. 4d ago First seen · 14 lines scan A 9f49dc392823

Subscribe to this mod's changes

FileChanged is a hook published in the GitHub repository taniwhaai/arai (7 stars, last pushed 22d 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.