# Design Implementation > Guide general software design and implementation choices. Use for feature work, refactors, or architecture decisions across this repo. Use when this capability is needed. - Skill: `tomevault-io/design-implementation` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/design-implementation` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/design-implementation/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/design-implementation --- Use this skill when shaping solutions that span multiple files or modules. Shared conventions - Follow [`AGENTS.md`](../../../AGENTS.md) for coding style, TypeScript/lint rules, and testing conventions. - Keep this skill focused on design and implementation tradeoffs. Principles - Follow [`AGENTS.md`](../../../AGENTS.md) for design-first, SOLID/DRY, and minimal-change guidance. - Design before implementation: confirm architecture choices before editing files. - Prefer small, focused changes over broad refactors. - Align with existing patterns and TypeScript strictness. Design checklist 1. Identify the smallest change that meets requirements. 2. Keep responsibilities narrow and testable. 3. Avoid cross-module coupling unless required. 4. Prefer explicit types over inference for exported APIs. 5. Update user-facing docs when behavior changes. Implementation checklist 1. Read the target files and match their style. 2. Avoid introducing new dependencies unless necessary. 3. Handle errors explicitly and surface user-visible errors via VS Code UI. 4. Add or update tests when behavior changes. 5. Keep code and docs synchronized. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/robinbreast) — claim your Tome and manage your conversions.