Sebastien developed and integrated a Manifest observability plugin as a dedicated skill for real-time AI agent monitoring in the davila7/claude-code-templates repository. His work focused on enabling live visibility into agent performance and cost metrics, supporting proactive tuning and cost control. Using Markdown for documentation and leveraging plugin development and observability tooling, Sebastien established a foundation for automated alerting and quality gates. The integration aligned with CI/CD practices and provided groundwork for future dashboards and diagnostics. Although the scope was limited to a single feature over one month, the implementation demonstrated depth in observability and real-time metrics integration for AI systems.