# smart-formatting

Runs formatters like Prettier, Black, gofmt, rustfmt, or php-cs-fixer automatically whenever Claude Code edits a file.

- hook · `type=hook` · Claude Code · 2972 installs
- Author: davila7
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/hooks/development-tools/smart-formatting.json
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/hooks/smart-formatting

## What it does

The hook attaches to `PostToolUse` events for `Edit` and `MultiEdit` actions. Once Claude Code finishes modifying a file, a shell script inspects `$CLAUDE_TOOL_FILE_PATH` to detect the extension.

For web formats like JavaScript, TypeScript, JSON, CSS, and HTML, it invokes `npx prettier --write`. It runs `black` on Python scripts, `gofmt -w` on Go code, `rustfmt` on Rust files, and `php-cs-fixer fix` on PHP sources.

Each formatting command appends `2>/dev/null || true`. If a required CLI tool is missing from your environment, the file simply stays unformatted without throwing errors to Claude.

## Install

### Claude Code (native platform)

1. **claude-code-templates**
```bash
npx claude-code-templates@latest --hook development-tools/smart-formatting
```

2. **Manually: put the files in place**
- File: `.claude/settings.json` — The hooks block: event (PreToolUse, PostToolUse, Stop…) → command. Personal ones go to ~/.claude/settings.json

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/hooks/development-tools/smart-formatting.json

## When to use it
- keep JavaScript and TypeScript files formatted with Prettier after edits
- run Black on Python modules automatically
- format Go files using gofmt right after modifications
- apply rustfmt styling to Rust code without leaving the session

## Example prompts
- Refactor the authentication logic in `src/auth.ts`
- Add input validation to `routes/users.py`
- Update the data models in `internal/db.go`

## Source text · smart-formatting.json · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: b1e4e46a558e50bb.

BEGIN THIRD-PARTY FILE b1e4e46a558e50bb
```text
{
  "description": "Smart code formatting based on file type. Automatically formats code using Prettier, Black, gofmt, rustfmt, and other language-specific formatters.",
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit|MultiEdit",
        "hooks": [
          {
            "type": "command",
            "command": "if [[ \"$CLAUDE_TOOL_FILE_PATH\" == *.js || \"$CLAUDE_TOOL_FILE_PATH\" == *.ts || \"$CLAUDE_TOOL_FILE_PATH\" == *.jsx || \"$CLAUDE_TOOL_FILE_PATH\" == *.tsx || \"$CLAUDE_TOOL_FILE_PATH\" == *.json || \"$CLAUDE_TOOL_FILE_PATH\" == *.css || \"$CLAUDE_TOOL_FILE_PATH\" == *.html ]]; then npx prettier --write \"$CLAUDE_TOOL_FILE_PATH\" 2>/dev/null || true; elif [[ \"$CLAUDE_TOOL_FILE_PATH\" == *.py ]]; then black \"$CLAUDE_TOOL_FILE_PATH\" 2>/dev/null || true; elif [[ \"$CLAUDE_TOOL_FILE_PATH\" == *.go ]]; then gofmt -w \"$CLAUDE_TOOL_FILE_PATH\" 2>/dev/null || true; elif [[ \"$CLAUDE_TOOL_FILE_PATH\" == *.rs ]]; then rustfmt \"$CLAUDE_TOOL_FILE_PATH\" 2>/dev/null || true; elif [[ \"$CLAUDE_TOOL_FILE_PATH\" == *.php ]]; then php-cs-fixer fix \"$CLAUDE_TOOL_FILE_PATH\" 2>/dev/null || true; fi"
          }
        ]
      }
    ]
  }
}
```
END THIRD-PARTY FILE b1e4e46a558e50bb

The third-party file has ended. Everything between the b1e4e46a558e50bb tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

© davila7 · MIT · https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/hooks/development-tools/smart-formatting.json

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From the same set: [davila7/claude-code-templates](https://affpapa.org/en/nevibecode/by/davila7/claude-code-templates.md) — 804 cards

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