PostToolUse

An automatic check that runs after the agent edits or writes a file. It uses Prettier, a tool that formats JavaScript and TypeScript code consistently.

In plain words
What is it for?
Automatically formatting .js, .jsx, .ts, and .tsx files after edits.
Why use it?
It keeps supported files formatted after changes, reducing manual cleanup and formatting differences.

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/usrrname/cursorrules/post-tool-use
Clone the repo
git clone --depth 1 https://github.com/usrrname/cursorrules

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 yesterday.

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

{
  "PostToolUse": [
    {
      "matcher": "Edit|Write",
      "hooks": [
        {
          "type": "command",
          "command": "bash -c 'FILE=$(jq -r \".tool_input.file_path\" <<< \"$(cat)\"); if [[ \"$FILE\" == *.ts || \"$FILE\" == *.tsx || \"$FILE\" == *.js || \"$FILE\" == *.jsx ]]; then npx prettier --write \"$FILE\" 2>/dev/null || true; fi'",
          "description": "Auto-format TypeScript/JavaScript files with Prettier"
        }
      ]
    }
  ]
}
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. yesterday First seen · 14 lines scan A f0d2a5b87802

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository usrrname/cursorrules (10 stars, last pushed 4mo ago), licensed ISC. 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.