January 2026: Delivered capture-aware I/O capture for tests in Buck2 and Buck2 Prelude, enabling ct:capture_start/stop/get in testshell debug mode. This capability ensures test outputs can be captured reliably across test runs, improving debugging and CI visibility. No major bugs were reported this month; the focus was on implementing the capture API and integrating it into the test harness. Key deliverables span Buck2 and Buck2 Prelude with the following commits: Buck2 - b572869b85c46ea915cf8c583aedb928f8fc4cd3; Buck2 Prelude - b68fb54187fdd471e4ef409c6ddf46aff65558e8. Impact includes deterministic test logs, faster diagnosis of failures, and a foundation for scalable test capture across the codebase. Technologies/skills demonstrated include test harness design, I/O capture mechanics, ct:capture_* API usage, and cross-repo collaboration for CI tooling.