Maciej Dragun enhanced the argument autofill experience in the scalameta/metals repository by refactoring the feature to display dynamic parameter labels, showing both parameter names and value placeholders within the IDE. Using Scala and applying IDE development best practices, he introduced automated tests to verify the new behavior, ensuring regression safety and maintainability. The change was delivered as a focused, low-risk update, traceable through a single commit, which supports easier rollbacks if needed. This work improved the clarity and accuracy of autofill actions, reducing user friction and enabling faster, more reliable code editing for developers working with Scala in Metals.