ralph-hook-fmt

A formatting hook plugin for Claude Code that automatically formats files after Write/Edit operations.

See lint hook: ralph-hook-lint

Features

• Automatic formatting: Files are formatted immediately after Write/Edit operations
• Multi-language support: JavaScript/TypeScript, Rust, Python, Java, Go
• Smart formatter detection: Automatically detects and uses the appropriate formatter for your project
• Non-blocking: Async, always continues after formatting

Supported Languages & Formatters

Language	Formatters (Priority Order)
JavaScript/TypeScript	oxfmt > biome format > prettier > dprint
Rust	rustfmt (via cargo fmt)
Python	ruff format > black > autopep8 > yapf
Java	spotless (Maven/Gradle) > google-java-format > palantir-java-format
Go	goimports + gofumpt > gofumpt > goimports > gofmt
JSON/JSONC/JSON5	oxfmt
YAML	oxfmt
TOML	oxfmt
HTML	oxfmt
Vue	oxfmt
CSS/SCSS/Less	oxfmt
Markdown/MDX	oxfmt
GraphQL	oxfmt
Handlebars	oxfmt

Installation

claude plugin marketplace add https://github.com/chenhunghan/ralph-hook-fmt.git
claude plugin install ralph-hook-fmt

Update Plugin

claude plugin marketplace update ralph-hook-fmt
claude plugin update ralph-hook-fmt@ralph-hook-fmt

Debug Mode

By default, the hook runs without --debug:

"command": "${CLAUDE_PLUGIN_ROOT}/bin/ralph-hook-fmt"

Without --debug, continue responses are compact ({"continue":true}) and do not include systemMessage.

To see formatter diagnostics in systemMessage (for example formatter selected/skipped/error details), manually add --debug in hooks.json:

1. Open ~/.claude/plugins/ralph-hook-fmt/hooks/hooks.json
2. Change the command from:

   "command": "${CLAUDE_PLUGIN_ROOT}/bin/ralph-hook-fmt"

   to:

   "command": "${CLAUDE_PLUGIN_ROOT}/bin/ralph-hook-fmt --debug"

Development

make test
make lint
make fmt
make ci

License

MIT