Worked on the agda/agda repository to enhance the reliability of Agda’s type-checking pipeline, focusing on refining polarity handling for the --polarity and --without-K options. Addressed a bug in the fitsIn function by ensuring polarity checks are bypassed when --without-K is enabled, which prevents incorrect type judgments in edge cases. Added regression tests to verify the combined behavior of these options, improving test coverage and supporting safer future refactoring. The work involved compiler development and type checking using Haskell and functional programming techniques, contributing to more robust type-checking logic for downstream projects that rely on Agda’s correctness.