OpenAPI Core Principles 1. Built-in, not Swashbuckle — .NET 10 ships as the official, framework-maintained OpenAPI solution. Swashbuckle was removed from templates in .NET 9 and is no longer recommended. 2. TypedResults drive the schema — automatically generates correct OpenAPI response schemas. does not. Always use . 3. Transformers over workarounds — Document, operation, and schema transformers compose cleanly. Use them for security schemes, global responses, and schema customization. 4. Metadata on every endpoint — Use , , on every endpoint. This metadata feeds directly into the OpenAPI sp…