api-handoff

api-handoff is a skill for Claude Code, Codex from Dannykkh/skill-olympus. It costs 24 tokens per session (1,092 once invoked), scanned A, original, MIT.

Documentation that explains how a backend API and a frontend should work together. It records endpoints, the data the frontend needs, and requirements shared between teams.

In plain words
What is it for?
Use it to prepare API handoffs, describe endpoint behavior, list frontend data needs, and record cross-team data requirements.
Why use it?
It reduces misunderstandings about request and response data before implementation begins. Teams can use it as a shared reference when connecting the interface to the backend.

Skill for Claude CodeCodex

Part of the skill-olympus plugin — 95 skills, 6 commands, 42 agents shipped together

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 skills/dannykkh/skill-olympus/api-handoff
Any agent
npx skills add Dannykkh/skill-olympus --skill api-handoff
Clone the repo
git clone --depth 1 https://github.com/Dannykkh/skill-olympus

Made for: Claude Code, Codex.

Or install skill-olympus, the plugin that ships this one along with the rest of its 95 skills, 6 commands, 42 agents.

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.

agentmods badge for api-handoff

README.md
[![agentmods](https://agentmods.dev/badge/skills/dannykkh/skill-olympus/api-handoff.svg)](https://agentmods.dev/skills/dannykkh/skill-olympus/api-handoff)
Your own site
<a href="https://agentmods.dev/skills/dannykkh/skill-olympus/api-handoff"><img src="https://agentmods.dev/badge/skills/dannykkh/skill-olympus/api-handoff.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,092 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 $0.00024 $0.01092
Opus 5 $0.00012 $0.00546
Sonnet 5 $0.00005 $0.00218
Haiku 4.5 $0.00002 $0.00109

Measured 4d ago against content hash 08b543842a55, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-handoff 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 4d 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.

skills/api-handoff/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Handoff

프론트엔드-백엔드 간 API 핸드오프 문서 생성. 양방향 지원.

모드 선택

모드 용도 트리거
Backend → Frontend API 완성 후 프론트 전달 "create handoff", "document API", "frontend handoff"
Frontend → Backend 데이터 요구사항 전달 "backend requirements", "what data do I need"

Mode 1: Backend → Frontend Handoff

No Chat Output: 핸드오프 문서만 생성. 설명 없음.

백엔드 개발 완료 후 프론트엔드에 전달하는 구조화된 문서 생성.

Workflow

  1. Collect context — feature, endpoints, DTOs, auth, edge cases 확인
  2. Create handoff filedocs/ai/<feature-name>/api-handoff.md
  3. Fill template — 모든 섹션 작성
  4. Double-check — 페이로드, auth, validation 검증

Output Template

# API Handoff: [Feature Name]

## Business Context
[2-4 sentences: 문제, 사용자, 중요성, 도메인 용어]

## Endpoints

### [METHOD] /path/to/endpoint
- **Purpose**: [1줄]
- **Auth**: [role/permission 또는 "public"]
- **Request**:
  ```json
  { "field": "type — description, constraints" }
  • Response (success):
    { "field": "type — description" }
    
  • Response (error): [HTTP codes: 422, 404 등]
  • Notes: [edge cases, rate limits, pagination]

Data Models / DTOs

[TypeScript interface 형식]

Enums & Constants

Value Meaning Display Label

Validation Rules

[프론트가 미러링할 검증 규칙]

Business Logic & Edge Cases

  • [비자명한 동작, 제약조건]

Integration Notes

  • Recommended flow: [fetch → select → submit → poll]
  • Optimistic UI: [safe 여부]
  • Caching: [cache headers]

Test Scenarios

  1. Happy path
  2. Validation error
  3. Not found
  4. Permission denied

---

## Mode 2: Frontend → Backend Requirements

> **No Chat Output**: 요구사항 문서만 생성.

프론트엔드가 백엔드에 데이터 요구사항을 전달.

### 핵심 원칙

| Frontend Owns | Backend Owns |
|---------------|--------------|
| 어떤 데이터 필요 | 데이터 구조 |
| 어떤 액션 존재 | 엔드포인트 설계 |
| UI 상태 처리 | 필드명, 타입 |
| 표시 요구사항 | 성능/캐싱 |

### Workflow

1. **Describe feature** — 화면, 사용자, 목표
2. **List data needs** — 표시할 데이터, 액션, 상태
3. **Surface uncertainties** — 모르는 비즈니스 규칙
4. **Leave room** — 백엔드 피드백 요청

Read the full file on GitHub · 152 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.

  1. 4d ago First seen · 152 lines · 24 tokens per session scan A 08b543842a55

Subscribe to this mod's changes

api-handoff is a skill published in the GitHub repository Dannykkh/skill-olympus (5 stars, last pushed 3d ago), licensed MIT. It adds 24 tokens to every session and 1,092 once invoked, about $0.0001 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.