/configure:formatting

Check and configure code formatting tools against modern best practices.

When to Use This Skill

Use this skill when...	Use another approach when...
Setting up Biome, Prettier, Ruff format, or rustfmt for a project	Running an existing formatter (`biome format`, `ruff format`)
Migrating from Prettier to Biome or Black to Ruff	Fixing individual formatting issues in specific files
Auditing formatter configuration for completeness and best practices	Configuring linting rules (`/configure:linting` instead)
Adding format-on-save and CI format checks	Setting up pre-commit hooks only (`/configure:pre-commit` instead)
Standardizing formatting settings across a monorepo	Editing `.editorconfig` or `.vscode/settings.json` manually

Context

Biome config: !find . -maxdepth 1 -name \'biome.json\'
Prettier config: !find . -maxdepth 1 $ -name '.prettierrc*' -o -name 'prettier.config.*' $
Ruff config: !grep -l 'tool.ruff.format' pyproject.toml
Black config: !grep -l 'tool.black' pyproject.toml
Rustfmt config: !find . -maxdepth 1 $ -name 'rustfmt.toml' -o -name '.rustfmt.toml' $
EditorConfig: !find . -maxdepth 1 -name \'.editorconfig\'
Package JSON: !find . -maxdepth 1 -name \'package.json\'
Python project: !find . -maxdepth 1 -name \'pyproject.toml\'
Rust project: !find . -maxdepth 1 -name \'Cargo.toml\'
Pre-commit: !find . -maxdepth 1 -name \'.pre-commit-config.yaml\'
Project standards: !find . -maxdepth 1 -name \'.project-standards.yaml\'

Parameters

Parse from $ARGUMENTS:

--check-only: Report compliance status without modifications
--fix: Apply all fixes automatically without prompting
--formatter <formatter>: Override formatter detection (biome, prettier, ruff, rustfmt)

Version Checking

CRITICAL: Before flagging outdated formatters, verify latest releases using WebSearch or WebFetch:

Biome: Check biomejs.dev or GitHub releases
Prettier: Check prettier.io or npm
Ruff: Check docs.astral.sh/ruff or GitHub releases
rustfmt: Bundled with Rust toolchain - check Rust releases

Execution

Execute this code formatting configuration workflow:

Step 1: Detect project languages and existing formatters

Check for language indicators and formatter configurations:

Indicator	Language	Detected Formatter
`biome.json` with formatter	JavaScript/TypeScript	Biome
`.prettierrc.*`	JavaScript/TypeScript	Prettier
`pyproject.toml` [tool.ruff.format]	Python	Ruff
`pyproject.toml` [tool.black]	Python	Black (legacy)
`rustfmt.toml` or `.rustfmt.toml`	Rust	rustfmt

Modern formatting preferences:

JavaScript/TypeScript: Biome (preferred) or Prettier
Python: Ruff format (replaces Black)
Rust: rustfmt (standard)

Step 2: Analyze current formatter configuration

For each detected formatter, check configuration completeness:

Config file exists with required settings (indent, line width, quotes, etc.)
Ignore patterns configured
Format scripts defined in package.json / pyproject.toml
Pre-commit hook configured
CI/CD check configured

Step 3: Generate compliance report

Print a formatted compliance report:

Code Formatting Compliance Report
==================================
Project: [name]
Language: [detected]
Formatter: [detected]

Configuration:  [status per check]
Format Options: [status per check]
Scripts:        [status per check]
Integration:    [status per check]

Overall: [X issues found]
Recommendations: [list specific fixes]

If --check-only, stop here.

Step 4: Install and configure formatter (if --fix or user confirms)

Based on detected language and formatter preference, install and configure. Use configuration templates from REFERENCE.md.

Install formatter package
Create configuration file (biome.json, .prettierrc.json, pyproject.toml section, rustfmt.toml)
Add format scripts to package.json or Makefile/justfile
Create ignore file if needed (.prettierignore)

Step 5: Create EditorConfig integration

Create or update .editorconfig with settings matching the formatter configuration.

Step 6: Handle migrations (if applicable)

If legacy formatter detected (Prettier -> Biome, Black -> Ruff):

Import existing configuration
Install new formatter
Remove old formatter
Update scripts
Update pre-commit hooks

Use migration guides from REFERENCE.md.

Step 7: Configure pre-commit hooks

Add formatter to .pre-commit-config.yaml using the appropriate hook repository.

Step 8: Configure CI/CD integration

Add format check step to GitHub Actions workflow.

Step 9: Configure editor integration

Create or update .vscode/settings.json with format-on-save and .vscode/extensions.json with formatter extension.

Step 10: Update standards tracking

Update .project-standards.yaml:

components:
  formatting: "2025.1"
  formatting_tool: "[biome|prettier|ruff|rustfmt]"
  formatting_pre_commit: true
  formatting_ci: true

Step 11: Print completion report

Print a summary of changes made, scripts added, and next steps (run format, verify CI, enable format-on-save).

For detailed configuration templates, migration guides, and pre-commit configurations, see REFERENCE.md.

Agentic Optimizations

Context	Command
Quick compliance check	`/configure:formatting --check-only`
Auto-fix all issues	`/configure:formatting --fix`
Check Biome formatting	`biome format --check --reporter=github`
Check Prettier formatting	`npx prettier --check . 2>&1
Check Ruff formatting	`ruff format --check --output-format=github`
Check rustfmt formatting	`cargo fmt --check 2>&1

Flags

Flag	Description
`--check-only`	Report status without offering fixes
`--fix`	Apply all fixes automatically without prompting
`--formatter <formatter>`	Override formatter detection (biome, prettier, ruff, rustfmt)

Examples

# Check compliance and offer fixes
/configure:formatting

# Check only, no modifications
/configure:formatting --check-only

# Auto-fix and migrate to Biome
/configure:formatting --fix --formatter biome

Error Handling

Multiple formatters detected: Warn about conflict, suggest migration
No package manager found: Cannot install formatter, error
Invalid configuration: Report parse error, offer to replace with template
Formatting conflicts: Report files that would be reformatted

configure-formatting