Worked on the aws-amplify/amplify-data repository to deliver flexible querying for multi-field composite sort keys, enabling partial input support for the beginsWith function across three or more fields. The approach involved updating the ModelPrimaryCompositeKeyInput to accept partial inputs, which allows for more granular and adaptable data queries. Safeguards were implemented to prevent malformed prefix queries, and comprehensive tests were added to validate the new behavior and ensure ongoing correctness. The work focused on data modeling and robust testing practices, utilizing TypeScript to enhance both performance and reliability for data-oriented querying within the Amplify Data platform.