During December 2025, this developer enhanced data integrity in the ClipboardHealth/core-utils repository by implementing a new ESLint rule targeting Mongoose upsert operations. The rule enforces the use of runValidators: true whenever upsert: true is specified, ensuring that data validation occurs during update operations and reducing the risk of invalid data being written. By integrating this rule at the linting stage, the developer automated the enforcement of best practices across the codebase. The work was accomplished using TypeScript, JavaScript, and ESLint, focusing on maintainability and code quality while addressing a common source of data consistency issues in Mongoose workflows.