During May 2025, Alex contributed to the cedar-policy/cedar repository by developing the Upsert Entities capability for the Cedar policy engine. This feature allows entities to be added or updated within an Entities struct, improving policy management efficiency and consistency. Alex refactored internal Rust methods to support upserts and implemented logic to recompute transitive closures after each upsert, ensuring data integrity across dependent policies. The work demonstrated a strong grasp of API design, data structures, and policy enforcement, focusing on maintainability and future scalability. No major bugs were addressed, reflecting a targeted and in-depth approach to feature development.