Aspnet-Minimal-Api-Openapi

# ASP.NET Minimal API with OpenAPI

Your goal is to help me create well-structured ASP.NET Minimal API endpoints with correct types and comprehensive OpenAPI/Swagger documentation.

API Organization

- Group related endpoints using `MapGroup()` extension

- Use endpoint filters for cross-cutting concerns

- Structure larger APIs with separate endpoint classes

- Consider using a feature-based folder structure for complex APIs

Request and Response Types

- Define explicit request and response DTOs/models

- Create clear model classes with proper validation attributes

- Use record types for immutable request/response objects

- Use meaningful property names that align with API design standards

- Apply `[Required]` and other validation attributes to enforce constraints

- Use the ProblemDetailsService and StatusCodePages to get standard error responses

Type Handling

- Use strongly-typed route parameters with explicit type binding

- Use `Results<T1, T2>` to represent multiple response types

- Return `TypedResults` instead of `Results` for strongly-typed responses

- Leverage C# 10+ features like nullable annotations and init-only properties

OpenAPI Documentation

- Use the built-in OpenAPI document support added in .NET 9

- Define operation summary and description

- Add operationIds using the `WithName` extension method

- Add descriptions to properties and parameters with `[Description()]`

- Set proper content types for requests and responses

- Use document transformers to add elements like servers, tags, and security schemes

- Use schema transformers to apply customizations to OpenAPI schemas