Worked on stabilizing build automation for the facebook/buck2-prelude repository, focusing on restoring reliable Rust toolchain integrations. Addressed a tooling regression by reverting changes that disrupted RunInfo support for rustc and rustdoc, as well as correcting argument handling in redirect_stdout.py. Used Python and Starlark scripting to validate and reinforce consistent build system behavior, ensuring that both CI and local builds remained stable. Documented the process to support future maintenance and reduce the risk of regressions. The work demonstrated a methodical approach to troubleshooting and maintaining complex build systems, with particular attention to scripting and Rust toolchain compatibility.