Configuration values should be defined in a single location and passed through proper data structures rather than duplicated across modules or stored in global state. This prevents inconsistencies, reduces error-prone code duplication, and improves maintainability. Avoid defining default values in multiple places: ```ocaml (* Bad: Duplicating default value *) let semgrepignore_filename = Option.value conf.semgrepignore_filename ~default:".semgrepignore" in (* Good: Use centralized default from Semgrepignore.ml *) Semgrepignore.create ?semgrepignore_filename:conf.semgrepignore_filename ``` Replace global configuration state with proper data structures: ```ocaml (* Bad: Global mutable state *) let custom_ignore_pattern : string option ref = ref None (* Good: Pass configuration through data types *) type config = { custom_ignore_pattern: string option; ... } let process_with_config config = ... ``` Ensure configuration consistency across different implementations (e.g., Python and OCaml components) by maintaining a single source of truth for feature flags and their requirements.