openapi

Guidance for OpenAPI, a standard document that describes how an HTTP or REST API works, including its endpoints, data formats and security rules.

In plain words
What is it for?
Use it to create, read or validate OpenAPI 3.x documents, define requests and responses, describe authentication and document API endpoints.
Why use it?
It helps keep API documentation accurate and consistent, and supports checking specifications before generating client or server code.

Skill for Claude CodeCodex

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/itechmeat/llm-code/openapi
Any agent
npx skills add itechmeat/llm-code --skill openapi
Clone the repo
git clone --depth 1 https://github.com/itechmeat/llm-code

Made for: Claude Code, Codex.

Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,166 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 $0.00073 $0.02166
Opus 5 $0.00036 $0.01083
Sonnet 5 $0.00015 $0.00433
Haiku 4.5 $0.00007 $0.00217

Measured 2d ago against content hash 15ce3bea843f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openapi 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 2d 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/openapi/SKILL.md · 368 lines

How it starts

The opening of the file, as written. The whole thing — 368 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenAPI Specification

This skill provides guidance for working with OpenAPI Specification (OAS) documents.

Current version: OpenAPI 3.2.0 (September 2025)

Quick Navigation

  • Document structure: references/document-structure.md
  • Operations & paths: references/operations.md
  • Schemas & data types: references/schemas.md
  • Parameters & serialization: references/parameters.md
  • Security: references/security.md

When to Use

  • Creating a new OpenAPI specification document
  • Describing HTTP API endpoints
  • Defining request/response schemas
  • Configuring API security (OAuth2, API keys, JWT)
  • Validating an existing OpenAPI document
  • Generating client/server code from specs

Document Structure Overview

An OpenAPI document MUST have either an OpenAPI Object or Schema Object at the root.

Required Fields

openapi: 3.2.0 # REQUIRED: OAS version
info: # REQUIRED: API metadata
  title: My API
  version: 1.0.0

Complete Structure

openapi: 3.2.0
info:
  title: Example API
  version: 1.0.0
  description: API description (supports CommonMark)
servers:
  - url: https://api.example.com/v1
paths:
  /resources:
    get:
      summary: List resources
      responses:
        "200":
          description: Success
components:
  schemas: {}
  parameters: {}
  responses: {}
  securitySchemes: {}
security:
  - apiKey: []
tags:
  - name: resources
    description: Resource operations

Core Objects Reference

Info Object

info:
  title: Example API # REQUIRED
  version: 1.0.0 # REQUIRED (API version, NOT OAS version)
  summary: Short summary
  description: Full description (CommonMark)
  termsOfService: https://example.com/terms
  contact:
    name: API Support
    url: https://example.com/support
    email: [email protected]
  license:
    name: Apache 2.0
    identifier: Apache-2.0 # OR url (mutually exclusive)

Server Object

servers:
  - url: https://api.example.com/v1
    description: Production
  - url: https://{environment}.example.com:{port}/v1
    description: Configurable
    variables:
      environment:
        default: api
        enum: [api, staging, dev]
      port:
        default: "443"

Read the full file on GitHub · 368 lines

Files

What ships with it

5 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. 2d ago First seen · 368 lines · 73 tokens per session scan A 15ce3bea843f

Subscribe to this mod's changes

openapi is a skill published in the GitHub repository itechmeat/llm-code (22 stars, last pushed 1mo ago), licensed MIT. It adds 73 tokens to every session and 2,166 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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