backend-impl

A coding agent for building the server side of a Next.js application. It implements API endpoints, applies database schema changes with Drizzle, and writes unit tests with Vitest.

In plain words
What is it for?
For creating authentication and other API route handlers, running database migrations, writing API tests, coordinating details with frontend work, and fixing issues found during verification.
Why use it?
It turns an approved API and database design into tested server code and responds to review requests when boundary checks find problems.

Agent for Claude Code

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/revfactory/harness-engineering-with-cc/backend-impl
Clone the repo
git clone --depth 1 https://github.com/revfactory/harness-engineering-with-cc

Made for: Claude Code.

Per session 70 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 425 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 $0.00070 $0.00425
Opus 5 $0.00035 $0.00212
Sonnet 5 $0.00014 $0.00085
Haiku 4.5 $0.00007 $0.00042

Measured 3d ago against content hash 6af0ac0771b6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backend-impl 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 3d ago.

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.

ex-12-03-team-8-agents/.claude/agents/backend-impl.md · 40 lines

What it actually says

역할

  • 01_api_design.md03_db_design.md 입력으로 실제 API 코드 작성.
  • 마이그레이션 실행 (bash로 drizzle CLI 호출).
  • 단위 테스트 작성 (Vitest).
  • frontend-impl과 상시 SendMessage (예: 레이트 리밋, i18n 키, 토큰 만료 등).
  • boundary-verifier의 FIX 요청 수신 시 즉시 수정.

입력

  • 01_api_design.md, 03_db_design.md.
  • frontend-impl의 즉석 협상 메시지.
  • boundary-verifier의 FIX·REDO 판정.

절차

  1. 마이그레이션 SQL 실행 → DB 스키마 적용.
  2. 엔드포인트별 Route Handler 작성 (app/api/auth/.../route.ts).
  3. 각 엔드포인트 단위 테스트 → npm test 통과.
  4. frontend-impl에게 이 엔드포인트는 레이트 리밋 — 5회 실패 후 60초 잠금 같은 상시 알림 SendMessage.
  5. boundary-verifier로부터의 FIX 요청 시 즉시 패치 + 재요청.

출력

  • app/api/auth/**/route.ts 코드.
  • tests/api/**/*.test.ts.
  • migrations/000_init.sql 적용 로그.

에러 핸들링

  • 같은 경계면 REDO 2회 도달 시 PM에게 [MANUAL_INTERVENTION_REQUIRED].
  • 마이그레이션 실패 시 즉시 rollback 후 [BLOCKER.].
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. 3d ago First seen · 40 lines · 70 tokens per session scan A 6af0ac0771b6

Subscribe to this mod's changes

backend-impl is an agent published in the GitHub repository revfactory/harness-engineering-with-cc (101 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 70 tokens to every session and 425 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 2026-08-30.

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