GPT-5.6 Luna is the smallest and lowest-cost model in OpenAI’s GPT-5.6 family. Use it for high-volume, latency-sensitive, or cost-sensitive agent work where Sol or Terra would be more than you need.

Strengths

  • Lowest GPT-5.6 pricing; good for prototyping, subagents, and high-volume loops.
  • Fast responses relative to larger GPT-5.6 variants.
  • Same family tool-calling and agent support as Sol and Terra.

Limitations

  • Not a frontier model. For harder problems where peak intelligence matters, GPT-5.6 Sol or GPT-5.6 Terra is the better pick.
  • Smaller capacity for long, open-ended reasoning chains.

Tools

GPT-5.6 Luna has access to all agent tools when used with Cursor including:

Learn more about how tools work and tool calling fundamentals.

Pricing

Cursor plans include two usage pools. GPT-5.6 Luna draws from the third-party Other Models pool, which charges at the rates below. All prices are per million tokens.

A Fast mode tier (gpt-5.6-luna-fast) is available for priority processing at 2x the standard rates.