What is feature-dev-guide?

A Korean-language development checklist for building new application features. It covers requirements, impact analysis, architecture, side effects, API code, types, state, and verification.

Use it to plan feature work, organize feature-based TypeScript code, review API and state changes, and check the implementation before release.

It gives developers a consistent sequence for thinking through a feature before and during implementation. This helps expose affected code, unclear requirements, and integration risks early.

feature-dev-guide — Cursor rule by Opti-kjh

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add rules/opti-kjh/palette/feature-dev-guide

Clone the repo

git clone --depth 1 https://github.com/Opti-kjh/palette

Made for: Cursor.

Per session 2,063 This file is loaded in full into every session.

When invoked 2,063 The same file — it is already loaded in full.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.02063	$0.02063
Opus 5	$0.01032	$0.01032
Sonnet 5	$0.00413	$0.00413
Haiku 4.5	$0.00206	$0.00206

Measured yesterday against content hash 7af8ca29c2fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

feature-dev-guide scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/feature-dev-guide.mdc · 228 lines

How it starts

The opening of the file, as written. The whole thing — 228 lines — stays where its author put it; the contents beside it link to each section on GitHub.

기능 개발 가이드 프롬프트 템플릿

이 템플릿은 새로운 기능을 개발할 때 따라야 할 단계별 가이드를 제공합니다.

개발 전 준비 단계

1. 요구사항 분석

기능 요구사항이 명확히 정의되었는가?
비즈니스 로직이 명확한가?
UI/UX 요구사항이 정의되었는가?
API 스펙이 정의되었는가?

2. 영향도 분석

기존 기능에 영향을 주는가?
다른 feature와의 연관성이 있는가?
전역 상태 변경이 필요한가?
데이터베이스 스키마 변경이 필요한가?

3. 아키텍처 설계

Feature-based 구조에 맞게 설계되었는가?
MVVM 패턴을 준수하는가?

디렉토리 구조가 적절한가?

src/features/[feature-name]/
├── api/           # API 호출
├── hooks/         # ViewModel (비즈니스 로직)
├── components/     # Feature 전용 컴포넌트
├── store.ts       # Feature 전용 Zustand store
└── types.ts       # Feature 타입 정의

개발 단계

1. 사이드이펙트 점검

절대 사이드이펙트가 발생해서는 안되며 다른 개발에 영향이 있어서도 안됩니다.

기존 코드와의 충돌 가능성 확인
전역 상태 변경 영향도 확인
API 호출 패턴 변경 영향도 확인
캐시 정책 변경 영향도 확인

2. MCP 및 Context7 활용

MCP 도구를 활용하여 개발
Context7을 이용해서 공식문서에서 제공하는 방식으로 구현
Sequential thinking을 통해 단계적 의사코드를 작성하고 개선

3. 코드 구현

TypeScript 타입 정의

필요한 타입을 src/features/[feature]/types.ts에 정의
공용 타입은 src/types/index.ts에 정의
any 타입 사용 최소화

API 서비스 구현

src/features/[feature]/api/에 API 호출 함수 구현
- Query/Mutation 함수 정의
- Query Key 규칙 준수: ['domain','resource',params]
src/services/[feature]APIService.ts에 서비스 함수 추가
- HTTP 호출만 담당 (비즈니스 로직 없음)
- 에러 처리 및 로깅 구현
로깅 규칙 준수
- 성공: console.log('✅ [API명] API 호출 성공: [URL] → [데이터개수]개 데이터 로드')
- 실패: console.error('❌ [API명] API 호출 실패 → [에러메시지]')

ViewModel (Hooks) 구현

src/features/[feature]/hooks/에 ViewModel 구현
- 파일명: use[Feature]ViewModel.ts 또는 use[Feature]Screen.ts
TanStack Query를 사용한 서버 상태 관리
- Query Key 규칙 준수: ['domain','resource',params]
- useQuery, useMutation 적절히 활용
Zustand를 사용한 로컬 UI 상태 관리
- Feature별 store: src/features/[feature]/store.ts
- 전역 store는 src/stores/에만 배치
비즈니스 로직은 ViewModel에만 포함
- Screen 컴포넌트는 ViewModel만 구독
- 서비스 함수 직접 호출 금지

컴포넌트 구현

src/features/[feature]/components/에 Feature 전용 컴포넌트
공용 컴포넌트는 src/components/에 배치
Screen 컴포넌트는 ViewModel 하나만 구독
서비스 함수를 직접 호출하지 않음

Read the full file on GitHub · 228 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 228 lines · 2,063 tokens per session scan A 7af8ca29c2fd

Subscribe to this mod's changes

feature-dev-guide is a cursor rule published in the GitHub repository Opti-kjh/palette (1 stars, last pushed 7mo ago), licensed MIT. It adds 2,063 tokens to every session, about $0.0103 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Backend and APIs Code review Git and workflow

feature-dev-guide