Worked on the Automattic/studio repository to optimize session replay performance, focusing on reducing UI hangs during the rehydration of long sessions with extensive persisted progress data. The approach involved skipping ephemeral tool progress entries during session replay, which streamlined the process and improved responsiveness. To ensure reliability, comprehensive tests were added to verify that conversation history replays correctly while ignoring progress ticks. The work leveraged TypeScript for robust type safety, CLI development skills for command-line tooling, and Vitest for thorough test coverage. This targeted feature addressed a specific performance bottleneck, enhancing both the efficiency and maintainability of the session replay functionality.