During December 2025, this developer delivered configurable variadic parameter validation for function invocations in the substrait-io/substrait-java repository. The work centered on introducing the parameterConsistency option within YAML extensions, enabling teams to enforce either consistent or varying argument types for variadic parameters. By validating these inputs at invocation time, the implementation reduced potential runtime errors and improved contract enforcement for function calls. The feature was developed using Java, with a focus on software validation and unit testing to ensure code quality. This contribution laid the groundwork for broader validation capabilities and demonstrated attention to maintainability and future extensibility within the codebase.