Worked on enhancing the reliability and coverage of the AflppRedQueen mutator within the AFLplusplus/LibAFL repository, focusing on robust mutation handling and improved test validation. Addressed u64 I2S mutation handling by implementing a big-endian replacement path and extended AflppCmpLogFnOperands to support variable-length operands, ensuring runtime log entries align with instrumented data. Developed a new test harness to validate RedQueen-based fuzzing across multiple comparison values, increasing the realism of testing scenarios. The work leveraged Rust programming, compiler design, and fuzz testing skills, resulting in improved compatibility and coverage for cmplog instrumentation in line with AFL++ behavior.