Coding with Claude Opus 5.5

DHH had Opus 5.5 one-shot a translation of the ttfx engine into assembler that runs up to 17 times faster.

Opus 5.5 built a simulated computer with an OS on top and games running on it, runnable in the browser.

Daniel gave three models the same task on his Mac app and found Opus 5.5 produced the best Apple HIG and Liquid Glass build.

Opus 5.5 completed a 24-hour chess-engine benchmark that produced a UCI-compatible engine.

Same prompt given to two models to build a physics Rube Goldberg machine; the poster reports Opus 5.5 took 62 minutes and $14.28 versus a far cheaper run on Astra.

Six months of building a terminal with built-in multiplexing and multi-machine workspaces using Claude Code, from a longtime terminal fan.

A format where a single .krate file is the whole application and runs unchanged on all three desktop OSes, demonstrated with a code editor packaged as one file.

Annoyed by a $49 renewal, the builder had Claude Code on Opus 5.5 write a database client in two days using about 10% of a weekly limit.