Code Quality Enforcement

Consistent tooling only delivers value if it is enforced. Style debates are a tax on code review bandwidth; automated formatting eliminates them. The tools below are selected for speed (all Rust or native binaries), minimal configuration overhead, and cross-language coherence.

mise + task = project entry points

In this framework, every project-level invocation — lint, test, build, deploy — is declared as a task in mise.toml and run via mise run <task> (or the mr alias). This replaces the sprawling Makefile, Justfile, scripts/*.sh, and package.json#scripts ecosystem with a single declarative file. Pre-commit hooks still use lefthook (it is specialized for git event dispatch), but what lefthook invokes is typically a mise task.

Python — Ruff

Ruff replaces flake8, isort, pyupgrade, and in most projects pylint as well. It runs in under 100ms on projects with tens of thousands of lines of Python. Configure it in pyproject.toml:

[tool.ruff]
line-length    = 100
target-version = "py312"

[tool.ruff.lint]
select = [
  "E",   # pycodestyle errors
  "W",   # pycodestyle warnings
  "F",   # pyflakes
  "I",   # isort
  "B",   # flake8-bugbear
  "C4",  # flake8-comprehensions
  "UP",  # pyupgrade
  "S",   # flake8-bandit (security)
]
ignore = ["S101"]  # allow assert in tests

[tool.ruff.format]
quote-style   = "double"
indent-style  = "space"
line-ending   = "lf"

Ruby — RuboCop

RuboCop with the rubocop-rails, rubocop-rspec, and rubocop-performance extension gems covers style, Rails idioms, test structure, and common performance antipatterns. Use .rubocop.yml to inherit from a shared team configuration distributed as a gem or a raw GitHub URL:

# .rubocop.yml
inherit_from:
  - https://raw.githubusercontent.com/myteam/rubocop-config/main/.rubocop.yml

AllCops:
  TargetRubyVersion: 3.3
  NewCops: enable
  Exclude:
    - "db/schema.rb"
    - "db/migrate/**/*"
    - "node_modules/**/*"
    - ".bundle/**/*"

Layout/LineLength:
  Max: 120

JavaScript/TypeScript — Biome

Biome replaces ESLint, Prettier, and import sorters for JS/TS projects. Like ruff for Python, it is a single Rust binary with near-instant execution. Configure via biome.json:

{
  "$schema": "https://biomejs.dev/schemas/1.9.0/schema.json",
  "organizeImports": { "enabled": true },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true,
      "correctness": { "noUnusedVariables": "error" },
      "suspicious":  { "noExplicitAny": "warn" }
    }
  },
  "formatter": {
    "enabled":      true,
    "indentStyle":  "space",
    "indentWidth":  2,
    "lineEnding":   "lf",
    "lineWidth":    100
  }
}

Pre-commit hooks — lefthook

Pre-commit hooks enforce quality gates at the last safe moment before code enters the repository. Use lefthook — a fast, dependency-free pre-commit runner available as a mise-managed binary — rather than the Python-based pre-commit framework, which introduces an additional runtime dependency.

# lefthook.yml  (committed to VCS)
pre-commit:
  parallel: true
  commands:
    ruff-format:
      glob: "*.py"
      run: mise exec -- ruff format {staged_files}

    ruff-lint:
      glob: "*.py"
      run: mise exec -- ruff check --fix {staged_files}

    rubocop:
      glob: "*.rb"
      run: bundle exec rubocop --autocorrect {staged_files}

    biome:
      glob: "*.{js,ts,jsx,tsx}"
      run: mise exec -- biome check --apply {staged_files}

    secrets-scan:
      run: >
        git diff --cached --name-only |
        xargs grep -l "PRIVATE\|SECRET\|API_KEY\|password" || true

pre-push:
  commands:
    test-python:
      glob: "*.py"
      run: mise run test

    test-ruby:
      glob: "*.rb"
      run: bundle exec rspec --format progress

    test-js:
      glob: "*.{ts,tsx}"
      run: bun test

Install lefthook once per machine via mise, then register hooks once per repository:

# One time per machine (or add to ~/.config/mise/config.toml)
mise use -g lefthook

# In each project
lefthook install

For a deeper treatment of lefthook's design choices, staged-files scoping, and hook types, see Tool-Enforced Practices.

Editor normalization — EditorConfig

EditorConfig is supported natively or via plugin in every major editor and IDE. It ensures consistent whitespace, line endings, and encoding regardless of operating system or editor preference — the only non-negotiable baseline for polyglot projects:

# .editorconfig  (committed)
root = true

[*]
charset                  = utf-8
end_of_line              = lf
insert_final_newline     = true
trim_trailing_whitespace = true
indent_style             = space
indent_size              = 2

[*.py]
indent_size = 4

[Makefile]
indent_style = tab

[*.md]
trim_trailing_whitespace = false