Developed a diagnostics infrastructure for TOML manifests in the software-mansion/scarb repository, focusing on improving error reporting and laying the groundwork for future diagnostic enhancements. The work introduced new data structures such as ManifestDiagnosticAnchor, ManifestDiagnosticData, and ManifestSemanticError, which were integrated into the error handling pipeline to enable more consistent and actionable semantic error reporting. By implementing centralized error propagation through wrap_manifest_error, the changes enhanced both developer experience and downstream reliability. This Rust-based solution emphasized robust error handling and data structure design, establishing a foundation for proactive quality gates and more maintainable workflows in manifest file management.