tuyv 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, orREMOVE_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.
- Parse context -- extract fields, determine
scan_path(domain-aware if specified), extractoutput_dir - Load detection patterns
- MANDATORY READ: Load
references/detection_patterns.mdfor language-specific Grep/Glob patterns - Select patterns matching project's
tech_stack
- MANDATORY READ: Load
- Scan codebase for violations (Layer 1)
- All Grep/Glob patterns use
scan_path(not codebase_root) - Graph acceleration (if available): IF
contextStore.graph_indexedOR.hex-skills/codegraph/index.dbexists:- 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. Raiselimitonly for deliberate drill-down. - Outline-first read:
outline(file_path)before reading large source files -- understand structure before analyzing principles.
- DRY (1.1-1.10):
- Follow step-by-step detection from
detection_patterns.md - Apply exclusions from
detection_patterns.md#exclusions
- All Grep/Glob patterns use
- 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
- Generate recommendations
- MANDATORY READ: Load
references/refactoring_decision_tree.mdfor pattern selection - Match each finding to appropriate refactoring pattern via decision tree
- MANDATORY READ: Load
- Collect findings with severity, location, effort, pattern_id, pattern_signature, recommendation
- Tag each finding with
domain: domain_name(if domain-aware) - Assign
pattern_signaturefor managed aggregation
- Tag each finding with
- Calculate score using penalty algorithm
- Write Report: Build full markdown report in memory per
references/templates/audit_worker_report_template.md, write to{output_dir}/ln-623--{domain}.md(or623-principles.mdin global mode) in single Write call. Include<!-- FINDINGS-EXTENDED -->JSON block with pattern_signature fields for cross-domain DRY analysis - 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 ONLYscan_path - Tag findings: Include
domainfield in each finding when domain-aware - Pattern signatures: Include
pattern_id+pattern_signaturefor every DRY finding - Context-aware: Use project's
principles.mdto 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, orREMOVE_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}.mdwith 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
Version: 5.0.0 Last Updated: 2026-02-08