uFawkesAI: Hook for Claude Code

.claude/settings.json

PostToolUse is a hook for Claude Code from paruff/uFawkesAI. Its token cost is not measured, scanned A, original, MIT.

An after-edit hook that runs when the agent finishes an Edit or Write action and formats supported source files.

In plain words
What is it for?
Use it to format TypeScript and JavaScript with Prettier, Python with Black, and Go or Rust with their standard formatters.
Why use it?
It keeps supported files in the configured formatter's style without requiring a separate formatting step after every edit.

Hook for Claude Code

Written for Claude Code: PostToolUse hook event.

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

One of 5 entries in settings.json upstream. Installing this one merges just its entry into your config; the other 4 are separate, each on its own page.

Reuse

Borrowing it

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

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/paruff/ufawkesai/post-tool-use/github.svg)](https://agentmods.dev/hooks/paruff/ufawkesai/post-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/paruff/ufawkesai/post-tool-use"><img src="https://agentmods.dev/badge/hooks/paruff/ufawkesai/post-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 PostToolUse

Your own site · 80×15
<a href="https://agentmods.dev/hooks/paruff/ufawkesai/post-tool-use"><img src="https://agentmods.dev/badge/hooks/paruff/ufawkesai/post-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 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

PostToolUse scanned grade A with 1 finding 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 25d 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

"command": "node -e \"const input=JSON.parse(require('fs').readFileSync(0,'utf-8')||'{}'); const p=(input.tool_input&&input.tool_input.file_path)||''; const {spawnSync}=require('child_process'); const path=require('path'
.claude/settings.json · 13 lines

What it actually says

{
  "PostToolUse": [
    {
      "matcher": "Edit|Write",
      "hooks": [
        {
          "type": "command",
          "command": "node -e \"const input=JSON.parse(require('fs').readFileSync(0,'utf-8')||'{}'); const p=(input.tool_input&&input.tool_input.file_path)||''; const {spawnSync}=require('child_process'); const path=require('path'); if(!p) process.exit(0); const ext=path.extname(p); const map={'.ts':['npx','-y','prettier','--write',p],'.js':['npx','-y','prettier','--write',p],'.py':['black',p],'.go':['gofmt','-w',p],'.rs':['rustfmt',p]}; const cmd=map[ext]; if(!cmd) process.exit(0); const r=spawnSync(cmd[0],cmd.slice(1),{stdio:'inherit'}); process.exit(r.status ?? 1);\""
        }
      ]
    }
  ]
}
Same file

What else settings.json configures

This page is one entry in a file that holds 5. 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. 25d ago First seen · 13 lines scan A 31ec64c84478

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository paruff/uFawkesAI (2 stars, last pushed yesterday), 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 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-27.