api-reference-documentation

api-reference-documentation is a skill for Claude Code, Codex from aj-geddes/useful-ai-prompts. It costs 46 tokens per session (605 once invoked), scanned A, original, MIT.

A guide to documenting APIs, which are services that let other software request data or actions. It covers REST, GraphQL, OpenAPI/Swagger, authentication, examples, and SDKs.

In plain words
What is it for?
Use it to create endpoint references, OpenAPI specifications, authentication and rate-limit instructions, webhook or versioning guides, and client-library documentation.
Why use it?
It gives developers the details they need to connect to an API without guessing endpoint behavior, required credentials, request formats, or responses.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create endpoint references, OpenAPI specifications, authentication and rate-limit instructions, webhook or versioning guides, and client-library documentation.

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Install with agentmods
npx agentmods add skills/aj-geddes/useful-ai-prompts/api-reference-documentation
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 aj-geddes/useful-ai-prompts --skill api-reference-documentation
Clone the repo
git clone --depth 1 https://github.com/aj-geddes/useful-ai-prompts

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-reference-documentation

README.md
[![agentmods](https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/api-reference-documentation.svg)](https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/api-reference-documentation)
Your own site
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/api-reference-documentation"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/api-reference-documentation.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 605 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
  • Socket pass 18 Mar 2026
  • Snyk pass 4 Mar 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 $0.00046 $0.00605
Opus 5 $0.00023 $0.00302
Sonnet 5 $0.00009 $0.00121
Haiku 4.5 $0.00005 $0.00060

Measured 8d ago against content hash 039d40cfd91a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

api-reference-documentation 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate-api.sh), 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-reference-documentation/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Reference Documentation

Table of Contents

Overview

Generate professional API documentation that developers can use to integrate with your API, including endpoint specifications, authentication, request/response examples, and interactive documentation.

When to Use

  • Documenting REST APIs
  • Creating OpenAPI/Swagger specifications
  • GraphQL API documentation
  • SDK and client library docs
  • API authentication guides
  • Rate limiting documentation
  • Webhook documentation
  • API versioning guides

Quick Start

Minimal working example:

openapi: 3.0.3
info:
  title: E-Commerce API
  description: |
    Complete API for managing e-commerce operations including products,
    orders, customers, and payments.

    ## Authentication
    All endpoints require Bearer token authentication. Include your API key
    in the Authorization header: `Authorization: Bearer YOUR_API_KEY`

    ## Rate Limiting
    - 1000 requests per hour for authenticated users
    - 100 requests per hour for unauthenticated requests

    ## Pagination
    List endpoints return paginated results with `page` and `limit` parameters.
  version: 2.0.0
  contact:
    name: API Support
    email: [email protected]
    url: https://example.com/support
  license:
    name: MIT
    url: https://opensource.org/licenses/MIT
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide Contents
OpenAPI Specification Example openapi: 3.0.3
List Products List Products

Best Practices

✅ DO

  • Use OpenAPI 3.0+ specification
  • Include request/response examples for every endpoint
  • Document all query parameters and headers
  • Provide authentication examples
  • Include error response formats
  • Document rate limits and pagination
  • Use consistent naming conventions
  • Include SDK examples in multiple languages
  • Document webhook payloads
  • Provide interactive API explorer (Swagger UI)
  • Version your API documentation
  • Include migration guides for breaking changes

Read the full file on GitHub · 101 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 8d ago First seen · 101 lines · 46 tokens per session scan A 039d40cfd91a

Subscribe to this mod's changes

api-reference-documentation is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (333 stars, last pushed 6mo ago), licensed MIT. It adds 46 tokens to every session and 605 once invoked, about $0.0002 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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