Worked on the storybookjs/storybook repository to enhance type safety within the ArgType.summary property, focusing on stabilizing core type definitions rather than introducing new features. Addressed a critical bug by updating the TypeScript type definitions to explicitly allow undefined values for ArgType.summary, thereby preventing potential runtime errors and improving the overall developer experience for Storybook consumers. The approach emphasized robust interface design and careful review to ensure minimal impact on the existing codebase. Leveraged TypeScript and interface design principles to standardize usage across the repository, resulting in more reliable and maintainable type definitions for future development efforts.