GPT-5.6 Luna Overview

GPT-5.6 Luna is the most cost-efficient model in OpenAI's GPT-5.6 family, aimed at cost-sensitive and high-volume workloads. It roughly maps to the nano tier from earlier GPT-5 families while keeping a 1,050,000 token context window, 128,000 max output tokens, image input support, structured outputs, function calling, and broad tool compatibility for classification, extraction, summarization, routing, and lightweight agent tasks.