July 2025: Delivered reliability and correctness improvements across two critical repositories, with notable impact on runtime stability and build tooling accuracy. In levizh/rt-thread, fixed pthread_cond_timedwait timeout wakeups, addressing incorrect semaphore decrement and interrupt handling to improve reliability of timed waits in the pthreads library. In rust-lang/cargo, corrected --no-proc-macro handling in cargo tree and expanded tests to cover edge kinds and interactions with exclusion flags and dependency ordering, ensuring flags are respected regardless of position. These changes reduce debugging time, improve build graph accuracy, and enhance developer productivity. Technologies demonstrated include pthreads synchronization, Rust/Cargo internals, parsing logic, and test-driven development.