During May 2025, Alex Barnard focused on backend reliability for the modelcontextprotocol/rust-sdk repository, addressing a resource leak in the server-sent events (SSE) server. He implemented a cleanup mechanism using Rust and the Tokio async runtime, ensuring that server-side sessions were properly removed from the transaction store when SSE clients disconnected. By monitoring the client’s sender channel and triggering cleanup on closure, Alex improved the server’s scalability and reliability under high client churn. His work demonstrated a strong grasp of concurrency, transactional session management, and Rust async patterns, resulting in more robust resource lifecycle management for the project.