Kristian Koci focused on backend development and testing for the CQCL/guppylang repository, addressing a nuanced bug in the expression checker related to parameter resolution. Using Python, he delivered a targeted fix that ensures imported parameters with aliases are correctly recognized, while out-of-scope usage is properly flagged as an error. This work required a careful approach to validation logic, improving the correctness and reliability of cross-module expressions without altering the API or impacting performance. By encapsulating the solution in a single, focused commit, Kristian enhanced the stability of parameter handling for users composing complex expressions in guppylang environments.