Claude Opus 5.5 vs GPT-6 Astra vs GPT-6 Sol: the effort knob matters more than the model

Cross-platform development frameworks like .NET MAUI, React Native, Flutter, and Ionic each involve specific compromises regarding productivity, UI consistency, and native integration. Simultaneously, the AI landscape saw the release of Claude Opus 5.5 and GPT-6 Sol on September 22, 2026, following the launch of GPT-6 Astra. While official comparisons from Anthropic and OpenAI lacked direct parity, Artificial Analysis evaluated all three models across ten tests to determine performance based on reasoning-effort levels and cost.