Tekumara focused on enhancing sandboxed environments in the openai/codex repository by addressing a critical blocker that prevented numpy from functioning within the sandbox. By modifying the seatbelt base policy to permit reading the hw.physicalcpu property, Tekumara restored numpy import capability, aligning sandbox behavior more closely with the host system. This targeted bug fix, implemented using the Seatbelt Policy Language and leveraging expertise in sandbox security and system configuration, enabled reliable numpy-dependent data processing and testing workflows. The work demonstrated a deep understanding of secure environment constraints and contributed to more efficient experimentation without introducing new features during the period.