Quality

Quality Persona

Orchestrates systematic code quality checks, safe refactoring, and documentation updates across three phases. Use this instead of individual refactoring or documentation skills when full production-readiness is required end-to-end. If unsure which skill applies, use skill-router.

Complexity Thresholds

| Metric | Threshold | Action | |---|---|---| | Cyclomatic Complexity | > 10 | Extract method | | Method Length | > 20 lines | Extract method | | Parameter Count | > 4 | Parameter object | | Nesting Depth | > 3 levels | Extract method | | Duplication | > 3 similar blocks | DRY violation | | Class Length | > 300 lines | Extract class |

Agent Phases

Phase 1: Conventions Review

Check code against Rails standards via skills/code-quality/apply-code-conventions (DRY/YAGNI/PORO/CoC/KISS compliance, linter as style source of truth, structured logging) and skills/code-quality/apply-stack-conventions (Rails + PostgreSQL patterns, Hotwire + Tailwind conventions, security best practices).

Key file patterns to review: app/controllers, app/models, app/services, app/jobs, spec/.

Tool Integration:

# Complexity and duplication
bundle exec rubocop --only Metrics/CyclomaticComplexity,Metrics/MethodLength,Metrics/ParameterLists,Metrics/AbcSize,Metrics/PerceivedComplexity

# Security
bundle exec brakeman --no-pager
bundle exec bundle-audit check --update

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Phase 2: Refactoring (Optional)

Decision Gate — Proceed if any threshold from the table above is exceeded; otherwise skip to Phase 3.

If refactoring is needed, follow TDD discipline:

TDD Enforcement for Refactoring

Before any code change:

1. testing/plan-tests — Choose the best characterization test to document current behavior
2. testing/write-tests — Write characterization test and verify it PASSES (documents current behavior)
3. Refactoring Checkpoint — Propose specific refactoring (e.g., "Extract calculate_discount method to DiscountCalculator class")
4. User Approval — Wait for explicit confirmation
5. Implement Refactoring — Make the structural change only
6. Verify PASS — Run characterization test to confirm behavior is preserved
7. Regression Check — Run full test suite to ensure no regressions

HARD GATE — Test Verification:

• Characterization test EXISTS and PASSES before refactoring
• Characterization test PASSES after refactoring (behavior preserved)
• Full test suite PASSES (no regressions)
• If test fails: Fix the refactoring, not the test

Follow skills/code-quality/refactor-code for specific extraction patterns and safety guidelines.

bundle exec rspec   # All tests must pass before proceeding to Phase 3

If gate fails: Fix the failing test or refactoring before proceeding to Phase 3.

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Phase 3: Documentation

Document public APIs via skills/ruby-core-skills/write-yard-docs (annotate all public methods with params, return values, and examples; update README/diagrams for architecture or API changes).

Output: Updated YARD comments, refreshed README sections

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HARD-GATE: Quality Before Merge

NEVER open PR before:

bundle exec rubocop        # Linter must pass
bundle exec erblint --lint-all  # ERB linter must pass
bundle exec rspec          # All tests must pass
bundle exec brakeman       # Security scan must pass

Plus: YARD docs complete for all public APIs.

If gate fails: Fix the failing item before opening PR.

Output Format

# Quality Report — [Date]

## Conventions Check
### Critical Violations (Must Fix)
- [CRITICAL] app/controllers/orders_controller.rb:42 — Method `process_payment` has cyclomatic complexity of 15 (> 10 threshold)
- [CRITICAL] app/models/user.rb:28 — Class has 450 lines (> 300 threshold), extract to service objects

### Warning Violations (Should Fix)
- [WARNING] app/services/order_service.rb:17 — Method `calculate_discount` has 6 parameters (> 4 threshold)

### Suggestion Violations (Nice to Have)
- [SUGGESTION] spec/models/order_spec.rb:12 — Test duplication detected, extract to shared examples

## Refactoring
- [x] / [ ] Required (threshold exceeded)
- Characterization tests added, methods extracted, all tests passing

## Documentation
- YARD coverage: 87% (improved from 65%)
- README updated: YES

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Error Recovery

RuboCop offenses after refactoring:

1. Run bundle exec rubocop -a for auto-correctable offenses
2. Fix remaining offenses manually — refactoring may have introduced style violations
3. Re-run full suite to ensure fixes don't break behavior

Characterization test fails after refactoring:

1. The refactoring changed behavior — this is a regression, not a test problem
2. Revert the refactoring change
3. Re-examine the extraction — ensure the new method/class preserves the exact contract
4. Try a smaller, more focused refactoring step

YARD generation errors:

1. Check for syntax errors in YARD tags (@param, @return, @raise)
2. Verify method signatures match YARD annotations
3. Run yard stats to identify undocumented public methods

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Anti-Patterns to Avoid

• Refactoring without tests: NEVER refactor without characterization tests passing first
• Fixing tests to match refactoring: If a test fails after refactoring, the refactoring broke behavior — fix the code, not the test
• Scope creep during quality pass: Don't add features during a quality review — only fix conventions, refactor, and document
• Skipping ERB linter: erblint catches view-layer issues that RuboCop misses
• Ignoring Brakeman warnings: Every Brakeman warning MUST be assessed — false positives should be annotated, not silently ignored
• Partial YARD coverage: All public methods MUST have YARD docs — don't skip "obvious" methods

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: igmarin
• Source: igmarin/rails-agent-skills
• License: MIT

Install and usage instructions live in the source repository linked above.