api-tester

api-tester is a skill for Claude Code, Codex from Dannykkh/skill-olympus. It costs 55 tokens per session (1,906 once invoked), scanned A, original, MIT.

A workflow for testing communication between a web frontend and backend service. It covers proxy settings, cross-origin access (CORS), login tokens, error responses, and file uploads.

In plain words
What is it for?
Use it to verify API connections, test authenticated requests and uploads, and investigate frontend-backend errors.
Why use it?
It helps identify whether a failed request comes from the frontend, backend, browser security, authentication, or configuration.

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-tester
Any agent
npx skills add Dannykkh/skill-olympus --skill api-tester
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-tester

README.md
[![agentmods](https://agentmods.dev/badge/skills/dannykkh/skill-olympus/api-tester.svg)](https://agentmods.dev/skills/dannykkh/skill-olympus/api-tester)
Your own site
<a href="https://agentmods.dev/skills/dannykkh/skill-olympus/api-tester"><img src="https://agentmods.dev/badge/skills/dannykkh/skill-olympus/api-tester.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,906 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00055 $0.01906
Opus 5 $0.00028 $0.00953
Sonnet 5 $0.00011 $0.00381
Haiku 4.5 $0.00006 $0.00191

Measured 4d ago against content hash 20c7ab48c8dd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-tester scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s http://localhost:8000/health || curl -s http://localhost:3001/health
skills/api-tester/SKILL.md · 234 lines

How it starts

The opening of the file, as written. The whole thing — 234 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Tester

프론트엔드 ↔ 백엔드 API 연동을 실제로 검증하는 테스트 스킬.

사용법

"로그인 API 테스트해줘"
"프론트-백엔드 연동 검증해줘"
"/api-tester"

워크플로우

1. 환경 감지

서버 실행 상태 확인:

# 백엔드 포트 확인
curl -s http://localhost:8000/health || curl -s http://localhost:3001/health

# 프론트엔드 포트 확인
curl -s http://localhost:3000 || curl -s http://localhost:5173

프록시 설정 확인 (vite.config.ts, next.config.js, package.json proxy 등):

# Vite 프록시
grep -r "proxy" vite.config.* 2>/dev/null

# Next.js rewrites
grep -r "rewrites\|destination" next.config.* 2>/dev/null

# CRA proxy
grep "proxy" package.json 2>/dev/null

2. CORS 검증

# preflight OPTIONS 요청
curl -v -X OPTIONS http://localhost:8000/api/users \
  -H "Origin: http://localhost:3000" \
  -H "Access-Control-Request-Method: POST" \
  -H "Access-Control-Request-Headers: Content-Type,Authorization" \
  2>&1 | grep -i "access-control"

기대 결과:

  • Access-Control-Allow-Origin: 프론트엔드 origin 포함
  • Access-Control-Allow-Methods: 필요한 HTTP 메서드 포함
  • Access-Control-Allow-Headers: Content-Type, Authorization 포함
  • Access-Control-Allow-Credentials: true (쿠키 사용 시)

3. 인증 흐름 검증

# 로그인 → 토큰 발급
TOKEN=$(curl -s -X POST http://localhost:8000/api/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"[email protected]","password":"test1234"}' \
  | jq -r '.token // .access_token // .accessToken')

echo "Token: ${TOKEN:0:20}..."

# 보호된 API 호출
curl -s http://localhost:8000/api/users/me \
  -H "Authorization: Bearer $TOKEN" | jq .

# 만료/잘못된 토큰
curl -s -w "\nHTTP Status: %{http_code}\n" \
  http://localhost:8000/api/users/me \
  -H "Authorization: Bearer invalid-token"

기대 결과:

  • 올바른 토큰: 200 + 사용자 정보
  • 잘못된 토큰: 401 Unauthorized
  • 토큰 없음: 401 또는 403

4. CRUD 엔드포인트 검증

# CREATE
curl -s -X POST http://localhost:8000/api/items \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"name":"테스트 항목","description":"테스트용"}' | jq .

# READ (목록)
curl -s http://localhost:8000/api/items \
  -H "Authorization: Bearer $TOKEN" | jq .

# READ (단건)
curl -s http://localhost:8000/api/items/1 \
  -H "Authorization: Bearer $TOKEN" | jq .

# UPDATE
curl -s -X PUT http://localhost:8000/api/items/1 \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"name":"수정된 항목"}' | jq .

# DELETE
curl -s -X DELETE http://localhost:8000/api/items/1 \
  -H "Authorization: Bearer $TOKEN" -w "\nHTTP: %{http_code}\n"

Read the full file on GitHub · 234 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 · 234 lines · 55 tokens per session scan A 20c7ab48c8dd

Subscribe to this mod's changes

api-tester is a skill published in the GitHub repository Dannykkh/skill-olympus (5 stars, last pushed 3d ago), licensed MIT. It adds 55 tokens to every session and 1,906 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.