Worked on enhancing runtime configurability for YJIT in both the ruby/ruby and sorbet/sorbet repositories, focusing on performance optimization and resource management. Developed features allowing dynamic adjustment of memory size and call threshold through the YJIT.enable API, supporting Ruby 3.5 and later. Implemented input validation and comprehensive tests in Ruby and C to ensure safe, predictable configuration changes at runtime. Extended type signatures and API surfaces to harmonize JIT configuration across projects, enabling consistent experimentation with minimal risk. The work emphasized robust testing, runtime configuration, and cross-repository alignment, leveraging skills in C programming, Ruby, and performance optimization.