Worked on the facebook/buck2-prelude repository to improve reliability and cross-version compatibility in the Buck2 prelude module, focusing on the test suite for Stub JAR generation. Addressed differences in Kotlin metadata between versions 2.0.x and 2.1.x by implementing dynamic handling in Java and Kotlin-based tests, which reduced test flakiness and ensured stable outcomes across compiler versions. Delivered a targeted fix to the Kotlin ABI test for version 2.1, directly enhancing build stability for downstream users. This work strengthened continuous integration reliability, accelerated feedback cycles, and laid the foundation for smoother Kotlin upgrades, leveraging skills in build systems and testing.