Worked on the assistant-ui/assistant-ui repository to resolve a UI reliability issue by fixing Sidebar thread list deduplication. Addressed a bug where active and archived thread lists could display duplicate entries due to concurrent updates, which risked race conditions in thread navigation. Applied safe state management and pre-append filtering of thread IDs using React and TypeScript, ensuring that updates to thread statuses did not introduce inconsistencies. This solution improved UI consistency and user trust by preventing duplicate threads from appearing. The work demonstrated attention to code quality and maintainability, aligning with repository standards for front end development and collaborative workflows.