During June 2025, S.G. focused on enhancing tactic syntax detection in the leanprover-community/mathlib4-nightly-testing repository. They addressed a parser reliability issue by updating the Lean parser to recognize the mrefine macro within Init.Tactics, which improved the accuracy of tactic usage counts in nightly tests. Using Lean and applying formal verification and theorem proving skills, S.G. implemented a targeted fix that increased the detected uses of mrefine, ensuring more comprehensive parser coverage. This work contributed to more reliable nightly testing and greater developer confidence in tactic parsing, reflecting a deep understanding of Lean’s macro system and parser internals.