This synthesis records claims and practices from the cited sources; reported outcomes and product capabilities have not been independently verified.
Vibe coding has matured into production-scale software where frontier models handle complex tasks autonomously through supervised orchestration. Ultracode mode in Opus 4.8 removes manual intervention by enabling Claude to invoke workflows independently; supervisory workflows delegate subgoals, route routine execution to cheaper models, and enforce quality gates. Two-model adversarial loops—one drafting, one reviewing—prove effective; GPT-5.5 consistently finds issues in both planning and code review. At ~$400/month for Opus 4.7 + GPT-5.5, end-to-end feature work costs equivalent to fractional dev teams. Design specs via DESIGN.md achieve 95%+ principal completion rates. Strong prompts engineer state traps explicitly, paste raw errors, and specify mode; written rules in instructions files have highest leverage. For large features, split into planning, specification, then parallel execution. GPT-5.6 Sol-class models exhibit a distinct failure mode: not incorrect code, but overbuilt code where a config change produces full frameworks and bug fixes produce unnecessary adapter layers. Overengineered AI code often passes tests cleanly, hiding problems until modification attempts. Avoiding committed media in PRs keeps repo size clean while preserving reviewer visibility. Humans read every diff before commit.