In this Azure Friday episode, Scott Hanselman and Sajee demonstrate the Azure Cosmos DB Agent Kit — a skill you install with one command that gives your coding agent 100+ Cosmos DB best-practice rules across data modeling, partitioning, query optimization, and SDK usage and much more. Using a multi-agent fitness coaching app as an example, they show how the kit caught a missing partition key filter that was leaking member data across tenants, recommended hierarchical partitioning for multi-tenant scale, and fixed a fan-out query—all before the code shipped to production. Chapters 00:00 - Introduction 00:33 - Meet Sajee & overview of the Cosmos DB Agent Kit 00:50 - The problem: partition key & query mistakes that cost money in production 02:32 - How the Agent Kit works: one install, 100+ rules across 12 categories 04:52 - Demo setup: fitness coaching multi-agent app with Cosmos DB 06:26 - Showing the data: missing partition key filter exposes other members' data 08:23 - Agent Kit findings: SQL injection, singleton pattern, fan-out queries 10:46 - Indexing best practices & query optimization recommendations 12:34 - Applying the fix: correct results and single-partition RU cost 13:13 - Wrap up & how to get started Recommended resources Azure Cosmos DB Agent Kit Agent Kit Repository Connect Scott Hanselman | Twitter/X: @SHanselman Sajeetharan | Twitter/X: @sajeetharan Azure Friday | Twitter/X: @AzureFriday Azure | Twitter/X: @Azure