OpenAgentsControl/.opencode/context/openagents-repo/examples/hooks/formatting-hook.md

Code Formatting Hook

Purpose: Auto-format files after Claude edits them

---

TypeScript/Prettier Hook

{
  "hooks": {
    "PostToolUse": [{
      "matcher": "Edit|Write",
      "hooks": [{
        "type": "command",
        "command": "jq -r '.tool_input.file_path' | { read file_path; if echo \"$file_path\" | grep -q '\\.ts$'; then npx prettier --write \"$file_path\"; fi; }"
      }]
    }]
  }
}

---

How It Works

1. Triggers after Edit or Write tool completes
2. Extracts file path from JSON input via jq
3. Checks if file is .ts extension
4. Runs prettier on matching files

---

Variations

Go files:

if echo "$file_path" | grep -q '\\.go$'; then gofmt -w "$file_path"; fi

Python files:

if echo "$file_path" | grep -q '\\.py$'; then black "$file_path"; fi

Multiple extensions:

if echo "$file_path" | grep -qE '\\.(ts|tsx|js|jsx)$'; then npx prettier --write "$file_path"; fi

---

Related

• ../../lookup/hook-events.md - Hook events reference
• ./protection-hook.md - File protection example

Reference: https://docs.anthropic.com/en/docs/claude-code/hooks