# Claude Opus 5.5 can now rebuild real programs from scratch — 18.5% on ProgramBench, up from 0% in May > Source: > Published: 2026-10-28 10:00:26+00:00 According to Jack Clark's Import AI (Oct 26), Claude Opus 5.5 (xhigh) now resolves 18.5% of ProgramBench's 200 from-scratch rebuild tasks — rewriting programs like SQLite, FFmpeg and ripgrep from a compiled binary and its docs. That is up from 0% when every model failed at the benchmark's May launch