Angel Ding enhanced error handling in the ethereum-optimism/infra repository by delivering a new feature for Proxyd that expands and standardizes error mapping across backend implementations. Focusing on backend development and error handling using Go, Angel introduced a generic framework that categorizes transaction-related errors more precisely, reducing ambiguity during incident response and improving overall reliability. The approach involved adding new error strings and creating a single-source structure to support future backend integrations. While the work was limited to one feature over a month, it demonstrated thoughtful depth in addressing error observability and laid a foundation for easier onboarding of additional backends.