ln-641-pattern-analyzer

Paths: File paths (shared/, references/, ../ln-*) are relative to skills repo root. If not found at CWD, locate this SKILL.md directory and go up one level for repo root.

Pattern Analyzer

L3 Worker that analyzes a single architectural pattern against best practices and calculates 4 scores.

Purpose & Scope

• Analyze ONE pattern per invocation (receives pattern name, locations, best practices from coordinator)
• Find all implementations in codebase (Glob/Grep)
• Validate implementation exists and works
• Calculate 4 scores: compliance, completeness, quality, implementation
• Identify gaps and issues with severity and effort estimates
• Return structured analysis result to coordinator

Out of Scope (owned by ln-624-code-quality-auditor):

• Cyclomatic complexity thresholds (>10, >20)
• Method/class length thresholds (>50, >100, >500 lines)
• Quality Score focuses on pattern-specific quality (SOLID within pattern, pattern-level smells), not generic code metrics

Input (from ln-640 coordinator)

- pattern: string          # Pattern name (e.g., "Job Processing")
- locations: string[]      # Known file paths/directories
- bestPractices: object    # Best practices from MCP Ref/Context7/WebSearch
- output_dir: string       # e.g., "docs/project/.audit/ln-640/{YYYY-MM-DD}"

Note: All patterns arrive pre-verified (passed ln-640 Phase 1d applicability gate with >= 2 structural components confirmed).

Workflow

MANDATORY READ: Load shared/references/two_layer_detection.md for detection methodology.

Phase 1: Find Implementations

MANDATORY READ: Load ../ln-640-pattern-evolution-auditor/references/pattern_library.md — use "Pattern Detection (Grep)" table for detection keywords per pattern.

IF pattern.source == "adaptive":
  # Pattern discovered by coordinator Phase 1b — evidence already provided
  files = pattern.evidence.files
  SKIP detection keyword search (already done in Phase 1b)
ELSE:
  # Baseline pattern — use library detection keywords
  files = Glob(locations)
  additional = Grep("{pattern_keywords}", "**/*.{ts,js,py,rb,cs,java}")
  files = deduplicate(files + additional)

Phase 2: Read and Analyze Code

FOR EACH file IN files (limit: 10 key files):
  Read(file)
  Extract: components, patterns, error handling, logging, tests

Phase 3: Calculate 4 Scores

MANDATORY READ: Load ../ln-640-pattern-evolution-auditor/references/scoring_rules.md — follow Detection column for each criterion.

Scoring process for each criterion:

1. Run the Detection Grep/Glob from scoring_rules.md
2. If matches found → add points per criterion
3. If anti-pattern/smell detected → subtract per deduction table
4. Document evidence: file path + line for each score justification

Phase 4: Identify Issues and Gaps

FOR EACH bestPractice NOT implemented:
  issues.append({
    severity: "HIGH" | "MEDIUM" | "LOW",
    category: "compliance" | "completeness" | "quality" | "implementation",
    issue: description,
    suggestion: how to fix,
    effort: "S" | "M" | "L"
  })

# Layer 2 context check (MANDATORY):
# Deviation documented in code comment or ADR? → downgrade to LOW
# Pattern intentionally simplified for project scale? → skip


gaps = {
  missingComponents: required components not found in code,
  inconsistencies: conflicting or incomplete implementations
}

Phase 5: Calculate Score

MANDATORY READ: Load shared/references/audit_worker_core_contract.md and shared/references/audit_scoring.md.

Diagnostic sub-scores (0-100 each) are calculated separately and reported in AUDIT-META for diagnostic purposes only:

• compliance, completeness, quality, implementation

Phase 6: Write Report

MANDATORY READ: Load shared/references/audit_worker_core_contract.md and shared/templates/audit_worker_report_template.md.

# Build pattern name slug: "Job Processing" → "job-processing"
slug = pattern.name.lower().replace(" ", "-")

# Build markdown report in memory with:
# - AUDIT-META (extended: score [penalty-based] + diagnostic score_compliance/completeness/quality/implementation)
# - Checks table (compliance_check, completeness_check, quality_check, implementation_check)
# - Findings table (issues sorted by severity)
# - DATA-EXTENDED: {pattern, codeReferences, gaps, recommendations}

Write to {output_dir}/641-pattern-{slug}.md (atomic single Write call)

Phase 7: Return Summary

Report written: docs/project/.audit/ln-640/{YYYY-MM-DD}/641-pattern-job-processing.md
Score: 7.9/10 (C:72 K:85 Q:68 I:90) | Issues: 3 (H:1 M:2 L:0)

Critical Rules

MANDATORY READ: Load shared/references/audit_worker_core_contract.md.

• One pattern only: Analyze only the pattern passed by coordinator
• Read before score: Never score without reading actual code
• Detection-based scoring: Use Grep/Glob patterns from scoring_rules.md, not assumptions
• Effort estimates: Always provide S/M/L for each issue
• Code references: Always include file paths for findings

Definition of Done

MANDATORY READ: Load shared/references/audit_worker_core_contract.md.

• All implementations found via Glob/Grep (using pattern_library.md keywords or adaptive evidence)
• Key files read and analyzed
• 4 scores calculated using scoring_rules.md Detection patterns
• Issues identified with severity, category, suggestion, effort
• Gaps documented (missing components, inconsistencies)
• Recommendations provided
• Report written to {output_dir}/641-pattern-{slug}.md (atomic single Write call)
• Summary returned to coordinator

Reference Files

• Scoring rules: ../ln-640-pattern-evolution-auditor/references/scoring_rules.md
• Pattern library: ../ln-640-pattern-evolution-auditor/references/pattern_library.md
• MANDATORY READ: shared/references/research_tool_fallback.md

Version: 2.0.0 Last Updated: 2026-02-08