ln-741-linter-configurator

Type: L3 Worker Category: 7XX Project Bootstrap Parent: ln-740-quality-setup

Configures code linting and formatting tools for TypeScript, .NET, and Python projects.

Purpose & Scope

Does:

• Detects which linter stack to configure based on project type
• Checks for existing linter configurations
• Generates appropriate config files from templates
• Installs required dependencies
• Verifies linter runs without errors

Does NOT:

• Configure pre-commit hooks (ln-742 does this)
• Set up test infrastructure (ln-743 does this)
• Modify source code

Supported Stacks

eslint.config.mjs

.prettierrc

.editorconfig

Directory.Build.props

ruff.toml

pyproject.toml

Phase 1: Check Existing Configuration

Before generating configs, check what already exists.

Files to Check:

eslint.config.*

.eslintrc*

.prettierrc*

prettier.config.*

.editorconfig

Directory.Build.props

ruff.toml

pyproject.toml

Decision Logic:

1. If config exists and is complete: SKIP (inform user)
2. If config exists but incomplete: ASK user to merge or replace
3. If no config exists: CREATE from template

Phase 2: Generate Configuration

Use templates from references/ folder. Customize placeholders based on project.

TypeScript/React:

1. Copy

   eslint_template.mjs

   to project root as

   eslint.config.mjs

2. Copy

   prettier_template.json

   as

   .prettierrc

3. Add scripts to

   package.json

   :

   • "lint": "eslint ."

   • "lint:fix": "eslint . --fix"

   • "format": "prettier --write ."

   • "format:check": "prettier --check ."

.NET:

1. Copy

   editorconfig_template.ini

   as

   .editorconfig

2. Copy

   directory_build_props_template.xml

   as

   Directory.Build.props

3. Ensure analyzers package reference included

Python:

1. Copy

   ruff_template.toml

   as

   ruff.toml

   • OR merge into existing

     pyproject.toml

     under

     [tool.ruff]

2. Add scripts to

   pyproject.toml

   or document commands

Phase 3: Install Dependencies

Install required packages for each stack.

TypeScript/React:

npm install -D eslint @eslint/js typescript-eslint eslint-plugin-react eslint-plugin-react-hooks eslint-config-prettier prettier

CRITICAL:

eslint-config-prettier

is REQUIRED to prevent ESLint/Prettier conflicts.

.NET:

• Analyzers configured via Directory.Build.props
• No separate install needed

Python:

pip install ruff
# OR with uv:
uv add --dev ruff

Phase 4: Verify Setup

After configuration, verify linter works.

TypeScript:

npm run lint
npm run format:check

Expected: Exit code 0

.NET:

dotnet format --verify-no-changes

Expected: Exit code 0

Python:

ruff check .
ruff format --check .

Expected: Exit code 0

On Failure: Check error output, adjust config, re-verify.

Critical Rules

RULE 1: Always include

eslint-config-prettier

when using ESLint + Prettier together.

RULE 2: Use ESLint flat config format (eslint.config.mjs), NOT legacy .eslintrc.

RULE 3: Ruff replaces Black, isort, flake8, and many other Python tools. Do NOT install them separately.

RULE 4: Never disable strict TypeScript rules without documented reason.

Definition of Done

• Appropriate config files created for detected stack
• Dependencies installed
• Lint command runs without errors on project source
• Format command runs without errors
• No ESLint/Prettier conflicts (eslint-config-prettier installed)
• User informed of available lint/format commands

Reference Files

Error Handling

pip install ruff

uv add ruff

Version: 2.0.0 Last Updated: 2026-01-10