The ASP.NET Minimal API OpenAPI skill provides developers with a structured approach to creating ASP.NET Minimal API endpoints while ensuring that they are well-documented using OpenAPI specifications. This skill emphasizes organizing related endpoints through the MapGroup() extension, which helps in maintaining clarity and structure within your API. For larger applications, it suggests using separate endpoint classes and a feature-based folder structure to keep your codebase manageable and scalable.

When it comes to defining request and response types, this skill encourages developers to create explicit DTOs and model classes, complete with validation attributes. By utilizing C# record types for immutable objects and applying meaningful property names, you can enhance the clarity of your API. The use of [Required] attributes and the ProblemDetailsService ensures that your API adheres to best practices for error handling and response standards.

Type handling is another critical aspect covered by this skill. It advocates for strongly-typed route parameters and the use of Results<T1, T2> to handle multiple response types effectively. Leveraging C# 10+ features, such as nullable annotations and init-only properties, helps keep your code modern and robust.

Finally, the skill guides you through the built-in OpenAPI documentation support introduced in .NET 9. It covers defining operation summaries, adding descriptions, and customizing your OpenAPI schemas with document and schema transformers. This comprehensive approach ensures that your APIs are not only functional but also well-documented and easy to understand for consumers.