What is 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.

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.

It turns an approved API and database design into tested server code and responds to review requests when boundary checks find problems.

backend-impl — Agent for Claude Code by revfactory

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.

Clone the repo

git clone --depth 1 https://github.com/revfactory/harness-engineering-with-cc

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/agents/revfactory/harness-engineering-with-cc/backend-impl/github.svg)](https://agentmods.dev/agents/revfactory/harness-engineering-with-cc/backend-impl)

Your own site

<a href="https://agentmods.dev/agents/revfactory/harness-engineering-with-cc/backend-impl"><img src="https://agentmods.dev/badge/agents/revfactory/harness-engineering-with-cc/backend-impl/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/agents/revfactory/harness-engineering-with-cc/backend-impl"><img src="https://agentmods.dev/badge/agents/revfactory/harness-engineering-with-cc/backend-impl.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

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. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.00070	$0.00425
Opus 5.5	$0.00028	$0.00170
Sonnet 5.5	$0.00014	$0.00085
Haiku 4.5	$0.00007	$0.00042

Measured 2mo ago against content hash 6af0ac0771b6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 2mo 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.md와 03_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

마이그레이션 SQL 실행 → DB 스키마 적용.
엔드포인트별 Route Handler 작성 (app/api/auth/.../route.ts).
각 엔드포인트 단위 테스트 → npm test 통과.
frontend-impl에게 이 엔드포인트는 레이트 리밋 — 5회 실패 후 60초 잠금 같은 상시 알림 SendMessage.
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.

2mo 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 (123 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 70 tokens to every session and 425 once invoked, about $0.0003 per session on Opus 5.5. 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.

Backend and APIs Databases

backend-impl next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
backend-implrevfactory/harness-engineering-with-cc	Agent	123	5mo ago	Apache-2.0	A	70	Claude Code
supabase-architectluanpdd/kit-mcp	Agent	5	5d ago	MIT	A	50	Claude Code
evolution-go-integratorluanpdd/kit-mcp	Agent	5	5d ago	MIT	A	53	Claude Code
cqrs-specialistmnzralee/claude-multi-agent-architecture	Agent	8	1mo ago	MIT	A	0	Claude Code
Backend Architectcriptogus/agent-evolve-network	Agent	252	2d ago	none	A	34	Claude Code
repositories-scaffoldervoro6yov/spec-driven-development	Agent	5	1mo ago	Apache-2.0	A	41	Claude Code
backend-architecteinverne/dotfiles	Agent	120	2d ago	GPL-3.0	A	41	Claude Code