GPT-5.6 Terra sits in the middle of OpenAI's GPT-5.6 family, framed by third-party commentary as the balanced option for serious professional work: more capable than the low-cost Luna tier, more affordable than the flagship Sol tier. Its API identifier is gpt-5.6-terra, and it was released to general availability on July 9, 2026 after a limited preview that began June 26. A GPT-5.6 Terra Pro variant is offered on at least one routing platform using the same underlying model with a pro reasoning mode aimed at higher-quality responses on complex tasks, giving users a tuning knob between standard and deeper reasoning behavior.

Terra is built to handle demanding everyday workflows rather than only lightweight queries, and its surroundings reflect that intent. It supports multimodal input alongside text output, plus reasoning, tool calling, structured output, and attachments, making it well suited to agents, document pipelines, and retrieval-heavy applications. With roughly a one-million-token that quick-info value budget and tiered pricing that lowers per-token costs inside a base that quick-info value window before stepping up for very long prompts, it is aimed at teams who need long-document reasoning and tool-using assistants without paying flagship rates for every call.