Charles Cote developed two cross-repository features focused on enhancing observability and privacy within the DataDog tracing stack. In dd-trace-py, he implemented HTTP referrer hostname tagging on APM spans, extracting and tagging the hostname from incoming HTTP requests to improve frontend origin tracing while safeguarding user privacy. For browser-sdk, he enabled propagation of user and account IDs through trace baggage headers, allowing richer end-to-end traceability when propagateTraceBaggage is enabled. His work demonstrated strong backend and full stack development skills, leveraging Python and TypeScript to strengthen distributed tracing standards and enable more actionable analytics without exposing sensitive information.