levnikolaevich/ln-623-duplication-overabstraction-auditor

Paths: File paths (references/, ../ln-*) are relative to this skill directory.

Duplication & Over-Abstraction Auditor (L3 Worker)

Type: L3 Worker

Specialized worker auditing duplication, over-abstraction, and unused extensibility.

Purpose & Scope

• Audit duplication and over-abstraction (DRY/KISS/YAGNI)
• Return structured findings with severity, location, effort, pattern_signature, recommendations
• Emit MERGE_DUPLICATION, REMOVE_ABSTRACTION, or REMOVE_YAGNI
• Calculate compliance score (X/10) for Duplication & Over-Abstraction category

Inputs

MANDATORY READ: Load references/audit_worker_core_contract.md and references/mcp_tool_preferences.md. Tool policy: You may run as an isolated subagent where host AGENTS.md is not in scope, so default to hex-line MCP first for file reads, search, and edits. Load references/mcp_integration_patterns.md only when MCP behavior is unclear.

Receives contextStore with: tech_stack, best_practices, principles, codebase_root, output_dir.

Domain-aware: Supports domain_mode + current_domain (see audit_output_schema.md#domain-aware-worker-output).

Use hex-graph first when clone groups, implementations, or semantic relationships materially improve the audit. Use hex-line first for local code reads when available. If MCP is unavailable, unsupported, or not indexed, continue with built-in Read/Grep/Glob/Bash and state the fallback in the report.

Workflow

Detection policy: use two-layer detection (candidate scan, then context verification); load references/two_layer_detection.md only when the verification method is ambiguous.

1. Parse context -- extract fields, determine scan_path (domain-aware if specified), extract output_dir
2. Load detection patterns
   • MANDATORY READ: Load references/detection_patterns.md for language-specific Grep/Glob patterns
   • Select patterns matching project's tech_stack
3. Scan codebase for violations (Layer 1)
   • All Grep/Glob patterns use scan_path (not codebase_root)
   • Graph acceleration (if available): IF contextStore.graph_indexed OR .hex-skills/codegraph/index.db exists:
     • DRY (1.1-1.10): audit_workspace(path=scan_path, verbosity="minimal", limit=5, clone_member_limit=3) -- each returned clone group = DRY candidate. Raise limits only for deliberate drill-down. Use clone kind and hotspot context for severity triage. Fall back to grep patterns if unavailable.
     • KISS inheritance: find_implementations(symbol) for abstract classes -- count implementations (1 = KISS candidate). Trace inheritance depth via graph.
     • Complexity: audit_workspace(path=scan_path, verbosity="minimal", limit=5) -- use returned hotspots to pre-identify complex functions for KISS/quality analysis. Raise limit only for deliberate drill-down.
     • Outline-first read: outline(file_path) before reading large source files -- understand structure before analyzing principles.
   • Follow step-by-step detection from detection_patterns.md
   • Apply exclusions from detection_patterns.md#exclusions
4. Analyze context per candidate (Layer 2)
   • DRY: read both code blocks to confirm true duplication (not just similar naming or shared interface)
   • KISS: check if abstraction serves DI pattern (valid single-impl interface) or is premature
   • YAGNI: check if feature flag was recently added (intentional) or dormant for months
5. Generate recommendations
   • MANDATORY READ: Load references/refactoring_decision_tree.md for pattern selection
   • Match each finding to appropriate refactoring pattern via decision tree
6. Collect findings with severity, location, effort, pattern_id, pattern_signature, recommendation
   • Tag each finding with domain: domain_name (if domain-aware)
   • Assign pattern_signature for managed aggregation
7. Calculate score using penalty algorithm
8. Write Report: Build full markdown report in memory per references/templates/audit_worker_report_template.md, write to {output_dir}/ln-623--{domain}.md (or 623-principles.md in global mode) in single Write call. Include <!-- FINDINGS-EXTENDED --> JSON block with pattern_signature fields for cross-domain DRY analysis
9. Return Summary: Return minimal summary (see Output Format)

Two-Layer Detection

Detection policy: use two-layer detection (candidate scan, then context verification); load references/two_layer_detection.md only when the verification method is ambiguous.

All findings require Layer 2 context analysis. Layer 1 finding without Layer 2 = NOT a valid finding. Before reporting, ask: "Is this violation intentional or justified by design?"

| Finding Type | Layer 2 Downgrade Examples | |-------------|--------------------------| | DRY | Modules with different lifecycle/ownership -> skip. Intentional duplication for decoupling -> skip | | KISS | Framework-required abstraction (e.g., DI in Spring) -> downgrade. Single implementation today but interface for testing -> skip | | YAGNI | Feature flag used in A/B testing -> skip. Config option used by ops team -> skip |

Audit Rules

1. DRY Violations (Don't Repeat Yourself)

MANDATORY READ: Load references/detection_patterns.md for detection steps per type.

| Type | What | Severity | Exception (skip/downgrade) | Default Recommendation | Effort | |------|------|----------|---------------------------|----------------------|--------| | 1.1 Identical Code | Same functions/constants/blocks (>10 lines) in multiple files | HIGH: business-critical (auth, payment). MEDIUM: utilities. LOW: simple constants <5x | Different lifecycle/ownership modules -> skip. Intentional decoupling -> skip | Extract function -> decide location by duplication scope | M | | 1.2 Duplicated Validation | Same validation patterns (email, password, phone, URL) across files | HIGH: auth/payment. MEDIUM: user input 3+x. LOW: format checks <3x | Different security contexts (auth vs public) -> skip | Extract to shared validators module | M | | 1.3 Repeated Error Messages | Hardcoded error strings instead of centralized catalog | MEDIUM: critical messages hardcoded or no error catalog. LOW: <3 places | User-facing strings requiring per-context wording -> downgrade | Create constants/error-messages file | M | | 1.4 Similar Patterns | Functions with same call sequence/control flow but different names/entities | MEDIUM: business logic in critical paths. LOW: utilities <3x | Modules with divergent evolution expected -> skip | Extract common logic (see decision tree for pattern) | M | | 1.5 Duplicated SQL/ORM | Same queries in different services | HIGH: payment/auth queries. MEDIUM: common 3+x. LOW: simple <3x | Different bounded contexts; shared DB is worse than duplication -> skip | Extract to Repository layer | M | | 1.6 Copy-Pasted Tests | Identical setup/teardown/fixtures across test files | MEDIUM: setup in 5+ files. LOW: <5 files | Tests intentionally isolated for clarity/independence -> downgrade | Extract to test helpers | M | | 1.7 Repeated API Responses | Same response object shapes without DTOs | MEDIUM: in 5+ endpoints. LOW: <5 endpoints | Responses with different versioning lifecycle -> skip | Create DTO/Response classes | M | | 1.8 Duplicated Middleware Chains | Identical middleware/decorator stacks on multiple routes | MEDIUM: same chain on 5+ routes. LOW: <5 routes | Routes with different auth/rate-limit requirements -> skip | Create named middleware group, apply at router level | M | | 1.9 Duplicated Type Definitions | Interfaces/structs/types with 80%+ same fields | MEDIUM: in 5+ files. LOW: 2-4 files | Types with different ownership/evolution paths -> skip | Create shared base type, extend where needed | M | | 1.10 Duplicated Mapping Logic | Same entity->DTO / DTO->entity transformations in multiple locations | MEDIUM: in 3+ locations. LOW: 2 locations | Mappings with different validation/enrichment rules -> skip | Create dedicated Mapper class/function | M |

Recommendation selection: Use references/refactoring_decision_tree.md to choose the right refactoring pattern based on duplication location (Level 1) and logic type (Level 2).

2. KISS Violations (Keep It Simple, Stupid)

| Violation | Detection | Severity | Exception (skip/downgrade) | Recommendation | Effort | |-----------|-----------|----------|---------------------------|---------------|--------| | Abstract class with 1 implementation | Grep abstract class -> count subclasses | HIGH: prevents understanding core logic | Interface for DI/testing -> skip. Framework-required (Spring, ASP.NET) -> skip | Remove abstraction, inline | L | | Factory for <3 types | Grep factory patterns -> count branches | MEDIUM: unnecessary pattern | Factory used for DI/testing swap -> downgrade | Replace with direct construction | M | | Deep inheritance >3 levels | Trace extends chain | HIGH: fragile hierarchy | Framework-mandated hierarchy (UI widgets, ORM models) -> downgrade | Flatten with composition | L | | Excessive generic constraints | Grep <T extends ... & ...> | LOW: acceptable tradeoff | Type safety for public API boundary -> skip | Simplify constraints | M | | Wrapper-only classes | Read: all methods delegate to inner | MEDIUM: unnecessary indirection | Adapter pattern for external API isolation -> skip | Remove wrapper, use inner directly | M |

3. YAGNI Violations (You Aren't Gonna Need It)

| Violation | Detection | Severity | Exception (skip/downgrade) | Recommendation | Effort | |-----------|-----------|----------|---------------------------|---------------|--------| | Dead feature flags (always true/false) | Grep flags -> verify never toggled | LOW: cleanup needed | A/B testing flags -> skip. Ops-controlled toggles -> skip | Remove flag, keep active code path | M | | Abstract methods never overridden | Grep abstract -> search implementations | MEDIUM: unused extensibility | Plugin/extension point in public library -> downgrade | Remove abstract, make concrete | M | | Unused config options | Grep config key -> 0 references | LOW: dead config | Env-specific configs (staging/prod) -> verify before flagging | Remove option | S | | Interface with 1 implementation | Grep interface -> count implementors | MEDIUM: premature abstraction | Interface for DI/testing mock -> skip | Remove interface, use class directly | M | | Premature generics (used with 1 type) | Grep generic usage -> count type params | LOW: over-engineering | Public library API designed for consumers -> skip | Replace generic with concrete type | S |

4. Evidence Gate

Do not report aesthetic preferences. A finding is valid only when the worker can show repeated code, an abstraction with no real variation point, or unused extensibility that adds maintenance cost.

| Issue | Required Evidence | Action | |-------|-------------------|--------| | Duplication | matching code blocks, repeated validation/query/mapping, or pattern_signature repeated across files | MERGE_DUPLICATION | | Over-abstraction | abstraction layer with one real implementation and no framework/testing need | REMOVE_ABSTRACTION | | YAGNI | feature flag, config option, generic, or extension point with no current use | REMOVE_YAGNI |

Scoring Algorithm

MANDATORY READ: Load references/audit_scoring.md.

Output Format

MANDATORY READ: Load references/templates/audit_worker_report_template.md.

Write JSON summary per references/audit_summary_contract.md. In managed mode the caller passes both runId and summaryArtifactPath; in standalone mode the worker generates its own run-scoped artifact path per shared contract.

Write report to {output_dir}/ln-623--{domain}.md (or 623-principles.md in global mode) with category: "Duplication & Over-Abstraction".

FINDINGS-EXTENDED block (required for this worker): After the Findings table, include a <!-- FINDINGS-EXTENDED --> JSON block containing all DRY findings with pattern_signature for managed aggregation. Follow references/templates/audit_worker_report_template.md.

pattern_id: DRY type identifier (dry_1.1 through dry_1.10). Omit for non-DRY findings.

pattern_signature: Normalized key for the detected pattern (e.g., validation_email, sql_users_findByEmail, middleware_auth_validate_ratelimit). Same signature in multiple domains triggers cross-domain DRY finding. Format is defined in references/detection_patterns.md.

Return summary per references/audit_summary_contract.md.

When summaryArtifactPath is absent, write the standalone runtime summary under .hex-skills/runtime-artifacts/runs/{run_id}/evaluation-worker/{worker}--{identifier}.json and optionally echo the same summary in structured output.

Report written: .hex-skills/runtime-artifacts/runs/{run_id}/audit-report/ln-623--users.md
Score: X.X/10 | Issues: N (C:N H:N M:N L:N)

Critical Rules

Apply the already-loaded references/audit_worker_core_contract.md.

• Do not auto-fix: Report only
• Domain-aware scanning: If domain_mode="domain-aware", scan ONLY scan_path
• Tag findings: Include domain field in each finding when domain-aware
• Pattern signatures: Include pattern_id + pattern_signature for every DRY finding
• Context-aware: Use project's principles.md to define what's acceptable
• Effort realism: S = <1h, M = 1-4h, L = >4h
• Exclusions: Skip generated code, vendor, migrations (see detection_patterns.md#exclusions)
• Unique angle: Audit only duplication, over-abstraction, and unused extensibility. Do not audit delivery gates, security, package health, local complexity metrics, architecture boundaries, or runtime lifecycle.
• Action required: Every finding uses MERGE_DUPLICATION, REMOVE_ABSTRACTION, or REMOVE_YAGNI.

Definition of Done

Apply the already-loaded references/audit_worker_core_contract.md.

• [ ] contextStore parsed (including domain_mode, current_domain, output_dir)
• [ ] scan_path determined (domain path or codebase root)
• [ ] Detection patterns loaded from references/detection_patterns.md
• [ ] All 3 checks completed (scoped to scan_path):
  • DRY (10 subcategories: 1.1-1.10), KISS, YAGNI
• [ ] Recommendations selected via references/refactoring_decision_tree.md
• [ ] Findings collected with severity, location, effort, action, pattern_id, pattern_signature, recommendation, domain
• [ ] Score calculated per references/audit_scoring.md
• [ ] Report written to {output_dir}/ln-623--{domain}.md with FINDINGS-EXTENDED block (atomic single Write call)
• [ ] Summary written per contract

Reference Files

• Detection patterns: references/detection_patterns.md
• Refactoring decision tree: references/refactoring_decision_tree.md

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Version: 5.0.0 Last Updated: 2026-02-08