api-testing

api-testing is a skill for Claude Code from fugazi/test-automation-skills-agents. It costs 78 tokens per session (1,247 once invoked), scanned A, original, MIT.

A set of tests for checking REST and GraphQL APIs, which are web interfaces that exchange data with applications. It covers request and response formats, authentication, errors, pagination, repeatable operations, limits, and contracts between services.

In plain words
What is it for?
Use it to write standalone API tests with Playwright or Java REST Assured for endpoint schemas, access control, error handling, pagination, idempotency, rate limits, and contract validation.
Why use it?
It catches problems in an API without driving a browser, such as invalid data formats, incorrect status codes, broken login checks, or inconsistent service agreements.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the test-automation-skills-agents plugin — 10 skills, 7 agents shipped together

Good fit Use it to write standalone API tests with Playwright or Java REST Assured for endpoint schemas, access control, error handling, pagination, idempotency, rate limits, and contract validation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fugazi/test-automation-skills-agents/api-testing
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.

Any agent
npx skills add fugazi/test-automation-skills-agents --skill api-testing
Clone the repo
git clone --depth 1 https://github.com/fugazi/test-automation-skills-agents

Made for: Claude Code.

Or install test-automation-skills-agents, the plugin that ships this one along with the rest of its 10 skills, 7 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-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/fugazi/test-automation-skills-agents/api-testing/github.svg)](https://agentmods.dev/skills/fugazi/test-automation-skills-agents/api-testing)
Your own site
<a href="https://agentmods.dev/skills/fugazi/test-automation-skills-agents/api-testing"><img src="https://agentmods.dev/badge/skills/fugazi/test-automation-skills-agents/api-testing/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.

agentmods 80×15 button for api-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/fugazi/test-automation-skills-agents/api-testing"><img src="https://agentmods.dev/badge/skills/fugazi/test-automation-skills-agents/api-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 78 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,247 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00078 $0.01247
Opus 5 $0.00039 $0.00624
Sonnet 5 $0.00016 $0.00249
Haiku 4.5 $0.00008 $0.00125

Measured 9d ago against content hash d3ba019779c1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

api-testing 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 9d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/api-health-check.sh, templates/playwright-api-spec.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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-testing/SKILL.md · 135 lines

How it starts

The opening of the file, as written. The whole thing — 135 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Testing (Playwright + REST Assured)

Comprehensive API testing skill covering both Playwright TypeScript (request fixture, Supertest, Zod) and Java (REST Assured, AssertJ, JSON Schema Validator).

When to Use This Skill

  • Create API tests for REST or GraphQL endpoints
  • Validate request/response schemas (Zod, JSON Schema)
  • Test authentication flows (OAuth2, JWT, API keys, Bearer tokens)
  • Verify error handling (400, 401, 403, 404, 409, 422, 500)
  • Test pagination, filtering, sorting edge cases
  • Validate idempotency for PUT/DELETE operations
  • Contract testing between services
  • Rate limiting validation

Do NOT Use For

  • Browser-driven UI flows (use playwright-e2e-testing for Playwright specs, or webapp-selenium-testing for Selenium)
  • Live interactive browser sessions or snapshots (use playwright-cli)
  • Visual/layout regression (out of scope — no DOM)
  • End-to-end journeys that must drive a real browser across pages

Prerequisites

Stack Requirements
TypeScript Node.js 18+, @playwright/test or supertest, zod
Java Java 21+, REST Assured 5.x, AssertJ, Jackson, json-schema-validator

Core Principles

  1. Schema validation on every response — never trust an unvalidated response
  2. Test all HTTP status codes — happy path AND error states
  3. Auth testing is mandatory — verify 401/403 for protected endpoints
  4. Data-driven — test with valid, invalid, boundary, and empty values
  5. Stateless where possible — each test cleans up or uses unique data

Quick Reference — Playwright

import { test, expect } from "@playwright/test";

test("GET /api/users returns 200 with valid schema", async ({ request }) => {
  const response = await request.get("/api/users");
  expect(response.ok()).toBeTruthy();
  const body = await response.json();
  expect(body).toMatchObject({ data: expect.any(Array) });
});

Read the full file on GitHub · 135 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. 9d ago First seen · 135 lines · 78 tokens per session scan A d3ba019779c1

Subscribe to this mod's changes

api-testing is a skill published in the GitHub repository fugazi/test-automation-skills-agents (233 stars, last pushed 6d ago), licensed MIT. It adds 78 tokens to every session and 1,247 once invoked, about $0.0004 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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