GPT-5.6 Luna’s 1M Context Window: Whole-Document Work on the Cheap Tier
The GPT-5.6 Luna API context window is a one-million-token input, with up to 128K tokens of output. What makes it notable is not the number, which the family shares, but that a one-million-token window sits on the cheap tier at $0.20 per million input tokens. The GPT-5.6 family pricing breakdown shows that all three rungs…