Levn Ln 740 Quality Setup

---
name: ln-740-quality-setup
description: Coordinates linters, pre-commit hooks, and test infrastructure setup
---

# ln-740-quality-setup

**Type:** L2 Domain Coordinator
**Category:** 7XX Project Bootstrap
**Parent:** ln-700-project-bootstrap

Coordinates code quality tooling configuration for the project.

---

## Purpose & Scope

**Does:**
- Detects project technology stack (TypeScript/React, .NET, Python)
- Checks for existing quality configurations
- Delegates to specialized workers for each quality aspect
- Verifies final configuration works correctly

**Does NOT:**
- Generate configuration files directly (workers do this)
- Modify source code
- Run in isolation (requires ln-720 structure first)

---

## When to Use

| Trigger | Action |
|---------|--------|
| After ln-720-structure-migrator completes | Automatic delegation from ln-700 |
| Manual quality setup needed | Invoke directly with project path |
| Existing project needs quality tools | Run with existing config detection |

---

## Workflow Overview

| Phase | Action | Output |
|-------|--------|--------|
| 1 | Stack Detection | Identified technologies |
| 2 | Existing Config Check | Skip/merge/replace decisions |
| 3 | Parallel Delegation | Worker invocations |
| 4 | Verification | Working quality pipeline |

---

## Phase 1: Stack Detection

Detect project technologies to determine which quality tools to configure.

**Detection Rules:**

| File Pattern | Technology | Linter Stack |
|--------------|------------|--------------|
| `package.json` + `tsconfig.json` | TypeScript/React | ESLint + Prettier |
| `*.csproj` or `*.sln` | .NET | editorconfig + Roslyn |
| `pyproject.toml` or `requirements.txt` | Python | Ruff |
| Multiple detected | Mixed | Configure all detected |

**Actions:**
1. Glob for technology indicators
2. Build technology list
3. Log detected stack to user

---

## Phase 2: Existing Configuration Check

Before delegating, check what configurations already exist.

**Config Files to Check:**

| Technology | Config Files |
|------------|--------------|
| TypeScript | `eslint.config.*`, `.prettierrc*`, `tsconfig.json` |
| .NET | `.editorconfig`, `Directory.Build.props` |
| Python | `ruff.toml`, `pyproject.toml [tool.ruff]` |
| Pre-commit | `.husky/`, `.pre-commit-config.yaml` |
| Tests | `vitest.config.*`, `pytest.ini`, `*.Tests.csproj` |

**Decision Matrix:**

| Existing Config | Action | Confirmation |
|-----------------|--------|--------------|
| None found | Create new | No |
| Partial found | Merge (add missing) | Ask user |
| Complete found | Skip | Inform user |
| User requests replace | Backup + replace | Yes |

---

## Phase 3: Parallel Delegation

> **CRITICAL:** All delegations use Task tool with `subagent_type: "general-purpose"` for context isolation.

**Prompt template:**
```
Task(description: "Quality setup via ln-74X",
     prompt: "Execute ln-74X-{worker}. Read skill from ln-74X-{worker}/SKILL.md. Stack: {detectedStack}",
     subagent_type: "general-purpose")
```

**Anti-Patterns:**
- ❌ Direct Skill tool invocation without Task wrapper
- ❌ Any execution bypassing subagent context isolation

Invoke workers for each quality aspect. Workers can run in parallel as they configure independent tools.

**Delegation Order:**

```
ln-740 (this)
    |
    +---> ln-741-linter-configurator (via Task tool)
    |         - ESLint/Prettier (TypeScript)
    |         - editorconfig/Roslyn (.NET)
    |         - Ruff (Python)
    |
    +---> ln-742-precommit-setup (via Task tool)
    |         - Husky + lint-staged (Node.js)
    |         - pre-commit framework (Python)
    |         - commitlint
    |
    +---> ln-743-test-infrastructure (via Task tool)
              - Vitest (TypeScript)
              - xUnit (.NET)
              - pytest (Python)
```

**Worker Invocation:**
```
Task(description: "Linter setup via ln-741",
     prompt: "Execute ln-741-linter-configurator. Stack: {stack}, configs: {existingConfigs}",
     subagent_type: "general-purpose")

Task(description: "Pre-commit setup via ln-742",
     prompt: "Execute ln-742-precommit-setup. Stack: {stack}, lintCommands: {lintCommands}",
     subagent_type: "general-purpose")

Task(description: "Test infra via ln-743",
     prompt: "Execute ln-743-test-infrastructure. Stack: {stack}, structure: {projectStructure}",
     subagent_type: "general-purpose")
```

---

## Phase 4: Verification

After all workers complete, verify the quality pipeline works.

**Verification Steps:**

| Check | Command | Expected |
|-------|---------|----------|
| Lint runs | `npm run lint` / `ruff check .` / `dotnet format --verify-no-changes` | No errors |
| Format runs | `npm run format:check` / `ruff format --check` | No changes needed |
| Tests run | `npm test` / `pytest` / `dotnet test` | Sample tests pass |
| Hooks work | Create test commit | Hooks trigger |

**On Failure:**
1. Log specific failure
2. Suggest fix or re-run specific worker
3. Do NOT mark as complete until verification passes

---

## Critical Rules

> **RULE 1:** Never overwrite existing user configurations without explicit confirmation.

> **RULE 2:** Workers run AFTER stack detection - do not invoke workers without knowing the stack.

> **RULE 3:** Verification phase is MANDATORY - quality setup is not complete until tools run successfully.

> **RULE 4:** eslint-config-prettier is REQUIRED when both ESLint and Prettier are configured.

---

## Definition of Done

- [ ] All detected technology stacks have appropriate quality tools
- [ ] Existing configurations preserved or backed up
- [ ] Lint command runs without errors
- [ ] Format command runs without errors
- [ ] Test command runs and sample tests pass
- [ ] Pre-commit hooks trigger on test commit
- [ ] User informed of all installed tools and commands

---

## Reference Files

| File | Purpose |
|------|---------|
| [stack_detection.md](references/stack_detection.md) | Detailed detection rules |
| [verification_checklist.md](references/verification_checklist.md) | Full verification checklist |

---

## Error Handling

| Error | Cause | Resolution |
|-------|-------|------------|
| No stack detected | Empty project | Ask user for intended stack |
| Worker failed | Missing dependencies | Install prerequisites, retry |
| Verification failed | Config error | Check specific tool output, fix |
| Hooks not working | Git not initialized | Run `git init` first |

---

**Version:** 2.0.0
**Last Updated:** 2026-01-10