For slightly more complex full-stack programming tasks, gpt-5.6-sol ultra and Claude Fabel 5 are finally in a usable state, with the latter being a bit stronger overall. Remember to always enable ultra mode for 5.6 sol—the results are noticeably different. For Fabel 5, high mode is usually enough unless you run into issues that can't be solved after a few tries. The safety guardrails on Fabel 5 aren't as strict as when it first launched. If you do run into issues, switching to opus 5 ultra code works fine too.