Sylvain contributed to the formancehq/fctl repository by delivering two targeted CLI usability features over a two-month period. He enhanced shell autocompletion by refactoring completion logic into dedicated Go functions, improving maintainability and reducing input errors for organization and stack ID commands. In the payments/pools module, Sylvain aligned CLI aliases with actual operations, replacing misleading options to reduce user error and streamline automation. His work focused on Go-based CLI development, emphasizing code clarity and long-term maintainability. These changes addressed real developer pain points, laying the groundwork for broader CLI consistency and improving the overall user experience for the fctl tool.