During April 2025, Exen focused on enhancing the stability and reliability of OAI-Compat tool call handling within the langgenius/dify repository. They addressed a bug in the backend by implementing logic to merge new tool calls with existing ones during response processing, reducing erroneous tool-call creation. Exen introduced a robust unique ID generator for tool calls, improving traceability across workflows. The work involved refactoring Python code for clarity and maintainability, with an emphasis on API development and unit testing. This targeted engineering effort improved error rates and maintainability, demonstrating depth in backend problem-solving and attention to workflow reliability in production systems.