Tarun Aggarwal developed the Index Advisor feature for the Azure/cosmos-explorer repository, delivering an end-to-end solution that empowers users to optimize indexing policies and improve query performance. He implemented a React-based UI tab within the Execute Query flow, enabling users to analyze current indexing policies, view both included and potential indexes, and update policies directly from the interface. Leveraging JavaScript and TypeScript, Tarun integrated query metrics analysis to suggest indexing improvements, helping users balance performance with write costs. The feature was thoroughly validated through QA and included documentation, reflecting a comprehensive approach to full stack development and front end testing.