Agent skill

Strangler Fig Patterns

by revfactory in revfactory/harness-100

레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드.

Apache-2.0Auto-check passedDevelopment

Install Strangler Fig Patterns

skills CLI
$ npx skills add revfactory/harness-100 --skill strangler-fig-patterns -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install revfactory/harness-100 strangler-fig-patterns --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .claude/skills && cp -r skills-src/ko/22-legacy-modernizer/.claude/skills/strangler-fig-patterns .claude/skills/strangler-fig-patterns && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
strangler-fig-patterns
GitHub stars
1.3k
Token cost
~962 tokens
SKILL.md length
269 words
Files
1
Skills in repo
464
Repo updated
First seen
Licence
Apache-2.0

At a glance

레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드.

  • Works in 5 steps: Strangler Fig Pattern → Branch by Abstraction → Parallel Run (Scientist 패턴) → …
  • Tasks that involve Refactoring
  • SKILL.md covers 패턴 카탈로그, 패턴 선택 의사결정 트리 and 위험 신호와 대응
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Strangler Fig Patterns is an agent skill from revfactory/harness-100. 레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드. 'strangler fig', '점진적 마이그레이션', '리팩토링 패턴', 'branch by abstraction', 'parallel run', '점진적 교체', '마이그레이션 패턴 선택' 등 레거시 전환 패턴 적용 시 이 스킬을 사용한다. refactoring-strategist와 migration-engineer의 패턴 선택·구현을 강화한다. 단, 전체 팀 오케스트레이션이나 프로젝트 관리는 이 스킬의 범위가 아니다.

Its SKILL.md is about 960 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development, covering Refactoring. The licence is Apache-2.0.

When your agent uses it

  • Tasks that involve Refactoring

Example prompts

  • “strangler fig”
  • “branch by abstraction”
  • “parallel run”
  • “/strangler-fig-patterns”

Requirements

  • Python 3

Workflow steps

5 steps, taken from the step headings in SKILL.md.

  1. Strangler Fig Pattern
  2. Branch by Abstraction
  3. Parallel Run (Scientist 패턴)
  4. Anti-Corruption Layer (ACL)
  5. Feature Toggle 전략

What it can do on your machine

Read from SKILL.md and the folder at commit 8e8d35c. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are python and yaml).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Strangler Fig Patterns loads about 962 tokens when it runs. Until then it costs about 81 tokens; SKILL.md has 269 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~81
When it runs · the whole SKILL.md, loaded when a task matches
~962

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from revfactory/harness-100 at commit 8e8d35c, republished under its Apache-2.0 licence (© revfactory). 269 words, ~962 tokens.

Download SKILL.mdSave it as .claude/skills/strangler-fig-patterns/SKILL.md (or your agent's skills folder).
name
strangler-fig-patterns
description
레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드. 'strangler fig', '점진적 마이그레이션', '리팩토링 패턴', 'branch by abstraction', 'parallel run', '점진적 교체', '마이그레이션 패턴 선택' 등 레거시 전환 패턴 적용 시 이 스킬을 사용한다. refactoring-strategist와 migration-engineer의 패턴 선택·구현을 강화한다. 단, 전체 팀 오케스트레이션이나 프로젝트 관리는 이 스킬의 범위가 아니다.

Strangler Fig Patterns — 점진적 마이그레이션 패턴 가이드

레거시 시스템 교체를 위한 검증된 패턴들의 상세 구현 방법론.

패턴 카탈로그

1. Strangler Fig Pattern

적용 조건: 모놀리스에서 새 시스템으로 점진적 전환이 필요할 때

┌─────────────────────────────────────────────┐
│                 라우터/프록시                  │
│  ┌──────────┐    ┌──────────────────────┐   │
│  │ 레거시    │ ←→ │ 새 시스템            │   │
│  │ (축소 중) │    │ (확장 중)            │   │
│  └──────────┘    └──────────────────────┘   │
└─────────────────────────────────────────────┘

구현 단계:

단계작업검증 기준롤백 방법
1. 인터셉터 삽입라우터/프록시 계층 추가기존 트래픽 100% 레거시 경유 확인인터셉터 제거
2. 기능 단위 추출가장 독립적인 기능부터 새 서비스로동일 입출력 검증 (Shadow Test)라우팅 복원
3. 트래픽 전환카나리 → 점진적 비율 증가에러율, 지연시간, 비즈니스 메트릭비율 0% 복귀
4. 레거시 제거이관 완료된 코드 삭제전환 완료 100% 확인N/A

추출 우선순위 매트릭스:

높은 비즈니스 가치
       │
  ③ Quick │ ① 최우선
    Wins  │  추출 대상
  ────────┼──────────→ 낮은 결합도
  ④ 후순위 │ ② 점진적
    보류   │  분리 후 추출
       │
낮은 비즈니스 가치
2. Branch by Abstraction

적용 조건: 내부 컴포넌트를 교체할 때 (같은 코드베이스 내)

python
# Step 1: 추상화 계층 삽입
class PaymentGateway(ABC):
    @abstractmethod
    def process(self, amount: Decimal) -> PaymentResult: ...

# Step 2: 레거시 구현 래핑
class LegacyPayment(PaymentGateway):
    def process(self, amount):
        return self.old_system.charge(amount)

# Step 3: 신규 구현
class ModernPayment(PaymentGateway):
    def process(self, amount):
        return self.stripe_client.create_charge(amount)

# Step 4: 피처 플래그로 전환
gateway = ModernPayment() if feature_flag('new_payment') else LegacyPayment()
3. Parallel Run (Scientist 패턴)

적용 조건: 교체 전에 신규 시스템의 정확성을 검증할 때

python
class Experiment:
    def run(self, input_data):
        control_result = self.legacy.execute(input_data)
        try:
            candidate_result = self.modern.execute(input_data)
            if not self.compare(control_result, candidate_result):
                self.report_mismatch(input_data, control_result, candidate_result)
        except Exception as e:
            self.report_error(input_data, e)
        return control_result  # 항상 레거시 결과 반환

비교 전략:

비교 수준방법허용 범위
정확 일치==0% 차이
구조적 일치스키마 비교필드 존재/타입 일치
의미적 일치비즈니스 규칙 기반도메인별 허용 오차
통계적 일치집계/분포 비교99.9% 일치율 이상
4. Anti-Corruption Layer (ACL)

적용 조건: 레거시와 신규 시스템이 공존해야 할 때 도메인 오염 방지

ACL 구성요소:

구성요소역할구현
Translator도메인 모델 변환DTO ↔ Domain Object 매핑
Adapter인터페이스 변환레거시 API → 현대 인터페이스
Facade복잡성 은닉레거시 다중 호출 → 단일 메서드
5. Feature Toggle 전략
yaml
toggles:
  # Phase 1: 개발 팀만
  new_user_service: { type: permission, users: ["dev-team"] }
  # Phase 2: 카나리 (10%)
  new_user_service: { type: gradual-rollout, percentage: 10, sticky: true }
  # Phase 3: 전면 전환
  new_user_service: { type: release, enabled: true }
  # Phase 4: 토글 제거 (레거시 코드 삭제)

패턴 선택 의사결정 트리

레거시 교체가 필요한가?
├── 외부 시스템/서비스 교체 → Strangler Fig
├── 내부 컴포넌트 교체
│   ├── 교체 전 검증 필요 → Parallel Run + Branch by Abstraction
│   └── 교체 확신 있음 → Branch by Abstraction
├── 레거시-신규 공존 장기화 → Anti-Corruption Layer
└── 모든 경우 → Feature Toggle 병용 권장

위험 신호와 대응

위험 신호의미대응
추출할 모듈이 10개 이상 의존결합도 과다ACL 삽입 후 점진적 의존성 정리
Parallel Run 불일치율 > 5%동작 차이 과다비즈니스 규칙 재검증, 엣지 케이스 수집
토글 수 > 20개 동시 활성토글 부채정기 토글 청소 스프린트 도입
마이그레이션 6개월 이상 지속병렬 운영 비용 증가범위 축소 또는 부분 Big Bang 검토

© revfactory, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in ko/22-legacy-modernizer/.claude/skills/strangler-fig-patterns of revfactory/harness-100.

Open the folder on GitHubat commit 8e8d35c

Compare with similar skills

Strangler Fig Patterns next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Strangler Fig Patterns compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Strangler Fig Patterns this skillrevfactory/harness-1001.3k—~962Automated safety check: PassApache-2.0
Guidelinesakash-network/node1.1k22 repos~577Automated safety check: PassMIT
Component Refactoringlangflow-ai/langflow156k—~3.5kAutomated safety check: PassMIT
Migrate Core Code to Submodulestinyhumansai/openhuman41k—~2.6kAutomated safety check: PassGPL-3.0
ast-grep Structural Searchcode-yeongyu/oh-my-openagent70k—~3.3kAutomated safety check: PassMIT
Systematic Code Refactoringluongnv89/claude-howto42k—~3kAutomated safety check: PassMIT

Similar skills

  • Guidelines

    akash-network/node

    Behavioral guidelines to reduce common LLM coding mistakes. An agent skill from akash-network/node.

    1.1k GitHub starsUsed in 22 repos~577 tokens
    DevelopmentAuto-check passed
  • Component Refactoring

    langflow-ai/langflow

    Refactor high-complexity React components in Langflow frontend.

    156k GitHub stars~3.5k tokensUpdated today
    DevelopmentAuto-check passed
  • Migrate Core Code to Submodules

    tinyhumansai/openhuman

    Plans and carries out moving non-host-specific code and its tests from the OpenHuman core into vendored tiny submodule libraries, then releases the submodule and re-pins the host.

    41k GitHub stars~2.6k tokensUpdated today
    DevelopmentAuto-check passed
  • ast-grep Structural Search

    code-yeongyu/oh-my-openagent

    Searches and rewrites code by syntax-tree shape across 25 languages with ast-grep, for codemods, structural queries and YAML lint rules, using a Python wrapper script.

    70k GitHub stars~3.3k tokensUpdated today
    DevelopmentAuto-check passed
  • Systematic Code Refactoring

    luongnv89/claude-howto

    Guides refactoring in phases based on Martin Fowler's method: research, test coverage check, planning and small tested steps, with your approval at each phase.

    42k GitHub stars~3k tokensUpdated 7 days ago
    DevelopmentAuto-check passed
  • Codex

    skills-directory/skill-codex

    A skill your agent uses when the user asks to run Codex CLI (codex exec, codex resume) or references OpenAI Codex for code analysis, refactoring, or automated editing

    1.5k GitHub starsUsed in 3 repos~1.8k tokens
    DevelopmentAuto-check passed

More from revfactory/harness-100

All 464 skills in this repo
  • Anti Bot Analyzer

    revfactory/harness-100

    A skill for analyzing website anti-bot defense mechanisms and developing legitimate evasion strategies.

    1.3k GitHub stars~1.1k tokensUpdated 6 mo ago
    Auto-check passed
  • API Error Design Patterns

    revfactory/harness-100

    Reference for designing how an API reports failures: structured error codes, response shapes, client-friendly messages, an error catalog and retry or fallback advice.

    1.3k GitHub stars~1.6k tokensUpdated 6 mo ago
    Auto-check passed
  • API Security Checklist

    revfactory/harness-100

    Walks a backend-dev agent through OWASP API Top 10 checks, authentication and authorization patterns, and defense code during API design.

    1.3k GitHub stars~1.7k tokensUpdated 6 mo ago
    Auto-check passed
  • Arg Parser Generator

    revfactory/harness-100

    Methodology for systematically designing and generating CLI tool argument parser structures.

    1.3k GitHub stars~1.2k tokensUpdated 6 mo ago
    Auto-check passed
  • Audience Segmentation

    revfactory/harness-100

    Audience segmentation skill used by the analyst and curator agents.

    1.3k GitHub stars~1.3k tokensUpdated 6 mo ago
    Auto-check passed
  • Audio Storytelling

    revfactory/harness-100

    Audio storytelling skill used by the podcast scriptwriter and show note editor.

    1.3k GitHub stars~1.6k tokensUpdated 6 mo ago
    Auto-check passed

Categories

Questions about Strangler Fig Patterns

What does Strangler Fig Patterns do?

레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드. Strangler Fig Patterns is an agent skill from revfactory/harness-100. 레거시 시스템을 점진적으로 교체하는 Strangler Fig 패턴과 관련 마이그레이션 패턴의 상세 구현 가이드.

When should I use Strangler Fig Patterns?

Strangler Fig Patterns fits situations like: tasks that involve Refactoring.

How do I install Strangler Fig Patterns in Claude Code?

Run `npx skills add revfactory/harness-100 --skill strangler-fig-patterns -a claude-code`. Or copy the skill folder (ko/22-legacy-modernizer/.claude/skills/strangler-fig-patterns in revfactory/harness-100) into .claude/skills/strangler-fig-patterns in your project. Claude Code loads it when a task matches its description.

How do I install Strangler Fig Patterns in Codex?

Run `npx skills add revfactory/harness-100 --skill strangler-fig-patterns -a codex`. Or copy the skill folder (ko/22-legacy-modernizer/.claude/skills/strangler-fig-patterns in revfactory/harness-100) into .agents/skills/strangler-fig-patterns in your project. Codex loads it when a task matches its description.

Can I use Strangler Fig Patterns in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add revfactory/harness-100 --skill strangler-fig-patterns -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/strangler-fig-patterns, .gemini/skills/strangler-fig-patterns, .github/skills/strangler-fig-patterns and .opencode/skills/strangler-fig-patterns in your project.

What does Strangler Fig Patterns need to run?

SKILL.md names no scripts, command-line tools or credentials: Strangler Fig Patterns is instructions for the agent only. Our summary lists: Python 3.

Does Strangler Fig Patterns access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Strangler Fig Patterns safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Strangler Fig Patterns use?

Strangler Fig Patterns is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Strangler Fig Patterns use?

About 962 tokens (SKILL.md is roughly 3.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Strangler Fig Patterns?

Skills that share tags, products or a category with Strangler Fig Patterns: Guidelines (akash-network/node, 1.1k stars), Component Refactoring (langflow-ai/langflow, 156k stars), Migrate Core Code to Submodules (tinyhumansai/openhuman, 41k stars) and ast-grep Structural Search (code-yeongyu/oh-my-openagent, 70k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Strangler Fig Patterns?

revfactory (a GitHub user) maintains it in revfactory/harness-100, which has 1,290 GitHub stars. The repository holds 464 skills in this directory. The repository was last updated on March 22, 2026.

Source: revfactory/harness-100 on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.