Eno contributed cross-repository performance and JSON formatting improvements to ruby/ruby and ruby/json, focusing on numeric-heavy workloads. He ported an optimized integer formatting algorithm from C++ to C, writing directly to buffers to reduce memory allocations and achieve a 32% speedup in benchmarks. Eno also enhanced JSON serialization by ensuring integer-like floats consistently end with .0, improving downstream interoperability and predictability. His work included updating documentation and clarifying licensing for the fpconv integration. Using C, Ruby, and JSON serialization expertise, Eno delivered well-tested, maintainable features that improved throughput, memory efficiency, and standards compliance across both repositories.