Worked on enhancing the Platformatic OpenAPI client by addressing dispatcher composition inefficiencies when throwOnError is enabled. Refactored the client to ensure the dispatcher is composed only once per session, reducing per-request overhead and improving both throughput and stability. The solution involved registering the throwOnError interceptor a single time, which streamlined error handling without altering existing features. Added regression tests to lock in the new behavior and verify reliability. All changes were implemented in JavaScript using Node.js, with a focus on API client development and robust testing practices. The work improved efficiency and reliability within the platformatic/platformatic repository.