# generate-oas

> Claude/Codex skill by [@42crunch-ai](https://omgskills.com/library/42crunch-ai/index.md) · 1 stars · Updated 2026-09-28

Generate a complete OpenAPI 3.0 (OAS) specification from an API codebase, a Postman or Insomnia collection, or both together. Use this skill whenever the user wants to generate, create, or derive an OpenAPI spec, reverse-engineer an API definition, document an existing API, or convert a Postman/Insomnia collection to OpenAPI — when there is no existing OAS file yet. Triggers on phrases like "generate OAS", "create an OpenAPI spec", "generate openapi.json", "document my API", "reverse-engineer spec", "convert postman to openapi", "convert insomnia to openapi", "postman collection to OAS", "insomnia collection to OAS", or any request to produce an OAS file from source material rather than from an existing spec.

## Install

```sh
git clone https://github.com/42Crunch-AI/claude-plugins /tmp/claude-plugins && ln -s /tmp/claude-plugins/plugins/api-security-testing/skills/generate-oas ~/.claude/skills/generate-oas
```

## From README

Generate an OpenAPI Specification Produces a complete, valid OpenAPI 3.0.x specification file (openapi.json) from one or two source materials: an API codebase (any language/framework), and/or an API client collection — either a Postman collection (v2.0 or v2.1, with an optional environment file) or an Insomnia collection (v4 JSON export, or v5 JSON/YAML export, with an optional separate environment export) No existing OAS file is required. When both a codebase and a collection are available, the codebase is treated as the primary source of truth for structure — routes, validation, security — and the collection is used to enrich the result with concrete, real-world examples and to surface any endpoint the codebase analysis missed. --- Entry Point Ask about sources one at a time, codebase first, in this order.

## Links

- HTML page: https://omgskills.com/library/42crunch-ai/claude-plugins/plugins/api-security-testing/skills/generate-oas/
- GitHub: https://github.com/42Crunch-AI/claude-plugins
- Author: [@42crunch-ai](https://omgskills.com/library/42crunch-ai/index.md)