During April 2025, this developer enhanced performance monitoring for block-building processes in the flashbots/op-rbuilder and flashbots/rbuilder repositories. They introduced comprehensive metrics to track flashblocks, messages sent, and invalid blocks, establishing consistent instrumentation across both codebases. By integrating these metrics into OpRBuilder and OpPayloadBuilder, they enabled detailed observability during block construction and transaction simulation. This work, implemented in Rust and focused on metrics and performance monitoring, provided unified, data-driven insights that support optimization, troubleshooting, and capacity planning. The changes improved visibility into the block-building workflow, allowing for faster issue resolution and more informed decision-making across the stack.