Coding agents write a lot of code now, and most of it is checked only by tests that the same agent wrote. Formal verification gives a better answer, but tools like Lean & TLA+ take years to learn. Apex puts one interface in front of them. You write what a function should do in plain English, or let Apex read your docstrings and tests. Apex picks the right engine between TLA+ , Lean & Fuzzing to verify your code. Compatible with your favorite coding agent. No formal verification experience needed.