# Prevent Generated Code Duplication > Detect and refactor duplicate logic introduced by generated code, including overlaps between generated artifacts and existing project code. Use when this capability is needed. - Skill: `tomevault-io/prevent-generated-code-duplication` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/prevent-generated-code-duplication` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/prevent-generated-code-duplication/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/prevent-generated-code-duplication --- ## Goal Prevent divergence and maintenance risk by consolidating duplicated logic created by code generation or by mixing generated and hand-written code. ## When to Use - New generated files duplicate logic already present in the project. - Generated output duplicates existing generated modules. - Generated code and hand-written code implement equivalent validation/parsing/mapping/error handling. - Reviews identify repeated blocks after schema/code generation. ## Rules 1. Treat generated-vs-existing duplication as high-priority technical debt and resolve in the same change when feasible. 2. Prefer extraction to shared runtime modules (helpers/utilities/services), not copy-paste edits across multiple generated files. 3. Keep codegen outputs thin: delegate behavior to shared functions where possible. 4. If generator templates are available, fix duplication at template/source level first. 5. If template-level fix is not feasible, add a small shared abstraction and route both generated and existing code through it. 6. Preserve behavior and public interfaces; avoid broad architecture changes unless required. 7. Validate with lint, typecheck, and relevant tests after deduplication. ## Workflow 1. Identify duplicate blocks and classify: - generated <-> generated - generated <-> hand-written 2. Pick dedup strategy: - template fix (preferred) - shared helper/module extraction 3. Refactor call sites to shared implementation. 4. Remove duplicated code paths. 5. Run verification (lint + typecheck + tests). 6. Document the dedup decision in change summary. ## Output Pattern 1. Duplicates found (files + intent). 2. Chosen dedup strategy and why. 3. Refactored shared location. 4. Verification results. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/davidruzicka) — claim your Tome and manage your conversions.