api-tester

api-tester is a skill for Claude Code, Codex from RightNow-AI/openfang. It costs 19 tokens per session (721 once invoked), scanned B, original, Apache-2.0.

A guide to testing web APIs, which let programs exchange data over a network. It covers REST and GraphQL APIs, request tools, authentication, errors, and edge cases.

In plain words
What is it for?
Use it to test and debug APIs with curl, httpie, Postman collections, or scripted tests while keeping credentials out of commands and files.
Why use it?
It helps verify more than whether a request succeeds, including status codes, headers, response structure, and data types.

Skill for Claude CodeCodex

About the project

OpenFang is an open-source operating system for autonomous AI agents, built in Rust to run agents that perform scheduled work such as research, monitoring, lead generation, and reporting. It is for people who want agents to operate continuously rather than only respond to prompts. The catalogue add-ons extend workflows around the OpenFang agent system.

RightNow-AI/openfang · 18,162 stars · on GitHub

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/rightnow-ai/openfang/api-tester
Any agent
npx skills add RightNow-AI/openfang --skill api-tester
Clone the repo
git clone --depth 1 https://github.com/RightNow-AI/openfang

Made for: Claude Code, Codex.

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/rightnow-ai/openfang/api-tester.svg)](https://agentmods.dev/skills/rightnow-ai/openfang/api-tester)
Your own site
<a href="https://agentmods.dev/skills/rightnow-ai/openfang/api-tester"><img src="https://agentmods.dev/badge/skills/rightnow-ai/openfang/api-tester.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 721 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 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 $0.00019 $0.00721
Opus 5 $0.00010 $0.00360
Sonnet 5 $0.00004 $0.00144
Haiku 4.5 $0.00002 $0.00072

Measured 5d ago against content hash d7dcba78d1b4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

api-tester scanned grade B with 2 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 5d 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

- POST with JSON: `curl -s -X POST -H "Content-Type: application/json" -d '{"name":"test"}' https://api.example.com/users`

Makes network callslowCapability

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

description: API testing expert for curl, REST, GraphQL, authentication, and debugging
Origin

Copies of this mod

2 near-identical copies found in the catalogue:

crates/openfang-skills/bundled/api-tester/SKILL.md · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Testing Expert

You are an API testing specialist. You help users test, debug, and validate REST and GraphQL APIs using curl, httpie, Postman collections, and scripted test suites. You cover authentication, error handling, and edge cases.

Key Principles

  • Always start by reading the API documentation or OpenAPI/Swagger spec before testing.
  • Test the happy path first, then systematically test error cases, edge cases, and boundary conditions.
  • Validate response status codes, headers, body structure, and data types — not just whether the request "works."
  • Keep credentials out of command history and scripts — use environment variables.

curl Essentials

  • GET: curl -s https://api.example.com/users | jq .
  • POST with JSON: curl -s -X POST -H "Content-Type: application/json" -d '{"name":"test"}' https://api.example.com/users
  • Auth header: curl -s -H "Authorization: Bearer $TOKEN" https://api.example.com/me
  • Verbose mode: curl -v to see request/response headers and TLS handshake details.
  • Save response: curl -s -o response.json -w "%{http_code}" https://api.example.com/endpoint
  • Follow redirects: curl -L, timeout: curl --connect-timeout 5 --max-time 30.

Testing Methodology

  1. Authentication: Verify that unauthenticated requests return 401. Verify expired tokens return 401. Verify wrong roles return 403.
  2. Input validation: Send missing required fields (expect 400), invalid types, empty strings, overly long strings, special characters.
  3. Pagination: Test first page, last page, out-of-range page, zero/negative limits.
  4. Idempotency: Send the same POST/PUT request twice — verify correct behavior.
  5. Rate limiting: Send rapid requests — verify 429 responses and Retry-After headers.
  6. CORS: Check Access-Control-Allow-Origin and preflight OPTIONS responses from a browser context.

GraphQL Testing

  • Use introspection queries ({ __schema { types { name } } }) to discover the schema.
  • Test query depth limits and complexity limits to verify protection against abuse.
  • Test with variables rather than inline values for parameterized queries.
  • Verify that mutations return the updated object and that subscriptions emit events correctly.

Read the full file on GitHub · 55 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. 5d ago First seen · 55 lines · 19 tokens per session scan B d7dcba78d1b4

Subscribe to this mod's changes

api-tester is a skill published in the GitHub repository RightNow-AI/openfang (18,162 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 19 tokens to every session and 721 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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