Worked on the AzureAD/microsoft-identity-web repository to enhance the On-Behalf-Of (OBO) token acquisition context, focusing on accurate user context and maintainability. Leveraged ASP.NET Core and C# to derive ClaimsPrincipal from incoming tokens, ensuring correctness during token acquisition. Introduced a new data transfer object to encapsulate user assertion token information, which improved observability and extensibility of the OBO event flow. Refined the OnBeforeTokenAcquisitionForOnBehalfOf path to clarify code structure and establish a single source of truth for user context. The work emphasized backend development best practices, resulting in a more robust and maintainable authentication flow for the repository.