February 16th, 2026

New this release:

• 🎉 (server, smithy-rs#4494) Automatically add smithy.framework#ValidationException to operations with constrained inputs. Previously, users had to either set addValidationExceptionToConstrainedOperations: true in codegen settings or manually add ValidationException to each operation. Now this happens automatically unless a custom validation exception (a structure with the @validationException trait) is defined in the model. When using a custom validation exception, users must explicitly add it to each applicable operation. The addValidationExceptionToConstrainedOperations flag is deprecated.