During June 2025, Dimitrios Economou developed parametrization and substitution support for CN programs in the rems-project/cn repository. He refactored core program handling and supporting modules to introduce a parametrized structure, enabling safer type checking and improved reuse of CN program patterns. By implementing cn_prog_sub_let, he facilitated substitutions within CN programs, allowing type checking of ghost arguments with substituted loads. This work, grounded in ML and leveraging skills in compiler development and type systems, laid the foundation for scalable and maintainable CN workflows. The depth of the changes supports future extensibility and demonstrates a thoughtful approach to functional programming challenges.