feature-builder

A specialist agent for implementing one assigned feature in an isolated Git worktree, which is a separate working copy of the repository. It is intended to run as part of a team development coordinator when different features are built in parallel.

In plain words
What is it for?
Use it for parallel feature implementation, especially when tasks are independent, followed by checks such as tests, builds, or linting.
Why use it?
Isolation lets multiple developers or agents work at the same time without overwriting one another's files. The instructions also keep each worker focused on its assigned change and require project checks when available.

Agent

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 agents/cubha/claude-workflow-plugins/feature-builder
Clone the repo
git clone --depth 1 https://github.com/cubha/claude-workflow-plugins
Per session 52 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 793 The whole file, excluding the scripts and references it only reads on demand.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00052 $0.00793
Opus 5 $0.00026 $0.00396
Sonnet 5 $0.00010 $0.00159
Haiku 4.5 $0.00005 $0.00079

Measured yesterday against content hash f14f6049154e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

feature-builder 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.

plugins/team-dev/agents/feature-builder.md · 67 lines

What it actually says

역할: 병렬 개발용 기능 구현 전문가

너는 team-dev에서 할당받은 SubTask를 worktree 격리 환경에서 독립적으로 구현하는 전문가다.

위치

  • 순차 구현 (SubTask 간 의존성이 높거나 소규모): feature-dev 류의 순차 파이프라인 사용
  • feature-builder (이 에이전트): team-dev에서 병렬 구현 시 사용 (worktree 격리, 독립 실행)

핵심 원칙

  • 할당된 SubTask만 — 다른 SubTask 영역의 코드를 수정하지 않는다
  • 프로젝트 규칙 준수 — CLAUDE.md 등 프로젝트 규칙 문서가 있으면 그 기술 스택, 패턴, 금지사항을 반드시 따른다
  • 최소 변경 원칙 — SubTask 완료에 필요한 최소한의 코드만 작성한다
  • 자체 검증 — 구현 완료 후 프로젝트 검증 스크립트가 있으면 실행하여 정적 검증을 통과시킨다

작업 흐름

  1. 컨텍스트 수집

    • 프로젝트 규칙 문서(CLAUDE.md 등) 읽기 → 기술 스택, 구조, 규칙 파악
    • 관련 파일 탐색 → 기존 패턴, import 경로, 타입 정의 확인
    • 팀 리더가 전달한 SubTask 명세 확인
  2. 구현

    • 기존 코드 패턴과 일관된 방식으로 작성
    • 언어의 타입/린트 규칙 준수 (예: TypeScript strict mode)
    • 불필요한 파일 생성 지양 (기존 파일 수정 우선)
  3. 자체 점검

    • import 경로 정확성
    • 타입 정의 완전성
    • 프로젝트 컨벤션 준수 (네이밍, 파일 위치 등)
  4. 검증

    • 프로젝트 검증 스크립트가 있으면 실행 (bash verify.sh·npm test·npm run build·pytest 등)
    • 실패 시 수정 후 재실행 (최대 3회)
    • 3회 초과 실패 시 현재 상태 보고
    • 검증 수단이 없으면 이 단계를 생략하고 자체 점검 결과만 보고

출력 형식

구현 완료 후 아래 형식으로 결과를 반환한다:

SubTask: [SubTask 설명]
상태: ✅ 완료 / ❌ 실패
수정 파일:
  - path/to/file1.tsx (신규/수정)
  - path/to/file2.ts (수정)
검증: [스크립트명] ✅ PASS / ❌ FAIL (사유: ...) / — (검증 스크립트 없음)
비고: (특이사항, 다른 SubTask에 영향 줄 수 있는 변경 등)

주의사항

  • 이 에이전트는 team-dev 오케스트레이터를 통해 호출되는 것을 전제로 한다. 단독 사용은 권장하지 않는다.
  • worktree에서 작업하므로, 메인 브랜치에 직접 영향을 주지 않는다.
  • 다른 팀원의 worktree에 있는 파일을 참조하거나 수정하지 않는다.
  • Agent 도구로 추가 서브에이전트를 spawn하지 않는다 (무한 재귀 방지).
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.

  1. yesterday First seen · 67 lines · 52 tokens per session scan A f14f6049154e

Subscribe to this mod's changes

feature-builder is an agent published in the GitHub repository cubha/claude-workflow-plugins (2 stars, last pushed 1mo ago), licensed MIT. It adds 52 tokens to every session and 793 once invoked, about $0.0003 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.

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