Hurui Rui developed a feature for the JetBrains/koog repository that enhances API compatibility by introducing a configurable field name for the AdditionalPropertiesFlatteningSerializer. This update allows developers to use snake_case for additional properties, aligning with OpenAI-compatible API conventions and reducing integration friction for downstream clients. The implementation focused on backward-compatible API design, ensuring existing integrations remained unaffected while providing new flexibility. Hurui utilized Kotlin for backend development and serialization, targeting changes specifically within the OpenRouter implementation to avoid unnecessary refactoring. The work demonstrated a thoughtful approach to serializer customization and addressed a concrete interoperability issue without introducing breaking changes.