GPT-5.6 Luna is the fast, cost-efficient model in OpenAI's GPT-5.6 series. It is suited for high-volume chat, classification, lightweight agentic workflows, and latency-sensitive reasoning tasks.
Added Jul 9, 2026
Context Window
1.1M
Max Output
128.0K
Input Price (Auto)
$0.20/1M
Output Price (Auto)
$1.20/1M
Cache Read (Auto)
$0.020/1M
Capabilities
Benchmarks
Benchmarks
Performance metrics and benchmarks
Sourced from Artificial Analysis.
Intelligence Index
52.3
Coding Index
71.4
Agentic Index
46.9
Reasoning
GPQA Diamond
Graduate-level scientific reasoning
91.1%
Better than 94% of models compared
HLE
Humanity's Last Exam
39.5%
Better than 93% of models compared
AA-LCR
Long context reasoning evaluation
78.3%
Better than 96% of models compared
GDPval-AA
Economically valuable tasks
53.5%
CritPt
Research-level physics reasoning
20.6%
Coding
SciCode
Python programming for scientific computing
52.5%
Better than 94% of models compared
Knowledge
AA-Omniscience Accuracy
Proportion of correctly answered questions
42.7%
AA-Omniscience Hallucination Rate
Rate of incorrect answers among non-correct responses
92.6%
Last updated Aug 18, 2026
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Compare GPT 5.6 Luna with similar models from the same provider or model family.
GPT 5.6 Luna Pro
openai/gpt-5.6-luna-proGPT-5.6 Luna with Pro reasoning mode. Pro mode performs more model work for difficult tasks; reasoning effort remains independently configurable and defaults to medium.
GPT 5.6 Sol
openai/gpt-5.6-solGPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series. It is suited for complex reasoning, coding, agentic workflows, command-line work, and multi-step professional tasks.
GPT 5.6 Sol Pro
openai/gpt-5.6-sol-proGPT-5.6 Sol with Pro reasoning mode. Pro mode performs more model work for difficult tasks; reasoning effort remains independently configurable and defaults to medium.
GPT 5.6 Terra
openai/gpt-5.6-terraGPT-5.6 Terra is the balanced model in OpenAI's GPT-5.6 series, positioned between flagship Sol and cost-efficient Luna. It is suited for everyday coding, reasoning, agentic work, and general professional tasks.
GPT 5.6 Terra Pro
openai/gpt-5.6-terra-proGPT-5.6 Terra with Pro reasoning mode. Pro mode performs more model work for difficult tasks; reasoning effort remains independently configurable and defaults to medium.
GPT Chat Latest
openai/gpt-chat-latestCompatibility chat alias that routes to GPT 5.6 Sol, the flagship GPT-5.6 tier for complex reasoning, coding, and agentic workflows.