During April 2025, Tuna enhanced secure YAML parsing in the ruby/psych and ruby/ruby repositories by developing and integrating the safe_load_stream feature. This addition enables safe, per-document processing of multiple YAML documents from a single stream, addressing security concerns and improving error reporting with filename context. Tuna applied secure coding practices and extensive testing in Ruby, focusing on robust exception handling and comprehensive coverage of edge cases. The work involved refactoring multi-document handling for maintainability and reliability, ultimately reducing YAML ingestion risks and increasing developer confidence in the libraries’ security and stability through well-tested, maintainable code and improved parsing workflows.