OpenAI: GPT-6 Luna
openai/gpt-6-luna- Modalities
- text+image+file->text
- In / out price
- $0.1 / $0.5
- Context
- 1.1M
- Released
- Sep 22, 2026
- Knowledge cutoff
- —
per 1M
GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol. It is suited for high-volume and latency-sensitive workloads such as chat, classification, and lightweight agentic...
Supported parameters
include_reasoningInclude reasoning
Include a reasoning summary in the response.
max_completion_tokensMax completion tokens
Same idea as max_tokens. Some newer models use this field instead.
max_tokensMax tokens
Upper bound on generated tokens. Output stops at the limit.
reasoningReasoning
Enable or configure reasoning. The fields differ by model.
reasoning_effortReasoning effort
How much compute to spend reasoning. Often low, medium, or high.
response_formatResponse format
For example json_object or json_schema, to constrain the shape.
seedSeed
A fixed seed helps reproduce sampling. It does not guarantee byte-identical output.
structured_outputsStructured outputs
Generate a parseable structure that follows a JSON Schema.
tool_choiceTool choice
Whether to call a tool: auto, none, or a named function.
toolsTools
Function definitions the model may call via tool_calls.
verbosityVerbosity
Ask the model for a shorter or longer answer.