Hands-On with Microsoft's PDD Kit: What Formal Verification Proves and Misses

A hands-on series tested Microsoft Research's PDD Kit on a 5,000-line Rust app, showing it can formally verify login correctness for all inputs—but specs never guarantee an answer, so hangs or extreme slowness slip through. The author urges asking what is proven and what is left unverified when tools claim formal verification.

2026-11-10 ~ 2026-11-10 · 4 related posts

• PDD Kit in action: Verus proves a 5,000-line Rust login correct for every input — krishnan · 2026-11-10
• What formal specs leave out: PDD Kit's login spec never promises an answer — krishnan · 2026-11-10
• PDD Kit plants one bug per spec clause — a clause that catches none constrains nothing — krishnan · 2026-11-10
• When a tool claims "formally verified," ask: what was proved, what's still allowed? — krishnan · 2026-11-10