Microsoft Research debuts PDD Kit for formally verifying agent-written code

Microsoft Research engineers Alex Lavaee and Matthai Philipose describe PDD Kit, a toolkit for what they call Proof-Driven Development. It walks a team through turning plain-language intent into a formal specification written in Verus, a proof language for Rust, then generates proofs that a coding agent's code meets that specification for every input. Where proofs cannot reach, such as a third-party cryptography library or a user interface, it substitutes tests and labels them as evidence rather than proof. PDD Kit runs inside GitHub Next's Chopin planning environment.