PostToolUse

An automatic check that runs after files are written or edited. It can format or lint common programming files and scan changed files for patterns that may indicate exposed secrets.

In plain words
What is it for?
Use it after editing JavaScript, TypeScript, Python, documentation, or configuration files to apply available style fixes and detect possible API keys, passwords, or private keys.
Why use it?
Small editing mistakes, style problems, and accidentally committed credentials can otherwise reach review or production. Running checks immediately provides an early warning.

Hook for Claude Code

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/rbah31/claude-code-workflow/post-tool-use
Clone the repo
git clone --depth 1 https://github.com/rbah31/claude-code-workflow

Made for: Claude Code.

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

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 2d 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 · 17 lines

What it actually says

{
  "PostToolUse": [
    {
      "matcher": "Write|Edit",
      "hooks": [
        {
          "type": "command",
          "command": "FILE=$(python3 -c \"import json,sys; d=json.load(sys.stdin); print(d.get('tool_input',{}).get('file_path',''))\" 2>/dev/null); if [ -z \"$FILE\" ] || [ ! -f \"$FILE\" ]; then exit 0; fi; EXT=\"${FILE##*.}\"; case \"$EXT\" in js|jsx|ts|tsx) npx eslint --fix \"$FILE\" 2>/dev/null || true ;; py) python -m ruff check --fix \"$FILE\" 2>/dev/null || python -m flake8 \"$FILE\" 2>/dev/null || true ;; esac"
        },
        {
          "type": "command",
          "command": "FILE=$(python3 -c \"import json,sys; d=json.load(sys.stdin); print(d.get('tool_input',{}).get('file_path',''))\" 2>/dev/null); if [ -z \"$FILE\" ] || [ ! -f \"$FILE\" ]; then exit 0; fi; EXT=\"${FILE##*.}\"; case \"$EXT\" in md|txt|rst|example|sample) exit 0 ;; esac; case \"$FILE\" in */.claude/*|*/docs/*) exit 0 ;; esac; if grep -qE 'AKIA[0-9A-Z]{16}|sk_live_[a-zA-Z0-9]{20,}|ghp_[a-zA-Z0-9]{30,}|-----BEGIN PRIVATE|-----BEGIN RSA|(SECRET|PASSWORD|API_KEY)[[:space:]]*=[[:space:]]*[a-zA-Z0-9/+]{16,}' \"$FILE\" 2>/dev/null; then echo \"SECURITY BLOCK: Possible hardcoded secret in $FILE — use environment variables instead\" >&2; exit 2; fi"
        }
      ]
    }
  ]
}
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. 2d ago First seen · 17 lines scan A 549943f76fe3

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository rbah31/claude-code-workflow (5 stars, last pushed 2mo 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.