# GPT-5.6 Sol **GPT-5.6 Sol** is the flagship tier of OpenAI's GPT-5.6 family. It leads the family on every benchmark and is built for the tasks where correctness matters more than cost: frontier coding, long-horizon agentic work, scientific research, and cybersecurity. --- ## The GPT-5.6 family GPT-5.6 ships as three tiers. The number is the generation; the name is the capability tier, so each tier can advance on its own schedule. - **Sol** (this model) — the flagship, for the hardest work. - **Terra** — balanced, for everyday production. GPT-5.5-level quality at roughly half the cost. - **Luna** — fast and affordable, for high-volume, latency-sensitive work. --- ## Reasoning effort Control how long the model reasons before answering with the `reasoning_effort` parameter: | Level | Description | |-------|-------------| | `none` (default) | Fast, low-latency responses | | `low` | Light reasoning with minimal overhead | | `medium` | Balanced reasoning an
