GPT-5.6 Luna
Cost-efficient GPT-5.6 model for fast, high-volume workloads
ECI STANDING#19 of 266
SCORE156.31154.06–158.86 CI
FRONTIER LAGLaunched 5.1 months behindScores about what GPT-5.3 Codex did in February 2026.
SCORES LIKE THESE MODELSGemini 3.8 FlashGoogle DeepMind · Sep 2026156.54Grok 4.6xAI · Aug 2026156.35Claude Opus 4.7Anthropic · Apr 2026156.34Claude Sonnet 5Anthropic · Jun 2026156.22
Full Epoch Capabilities Index ranking ↗From the lab
Launch announcement · Jul 9, 2026GPT-5.6: Frontier intelligence that scales with your ambitionRELEASE DATEJul 9, 2026
WEIGHTSClosed weights
CONTEXT WINDOW1.05M
MAX OUTPUT128K
REASONINGYes
TOOL CALLINGYes
INPUTStext, image, pdf
OUTPUTStext
Specifications from Models.dev. Availability and limits may differ by provider. Benchmark scores come from Epoch AI under CC BY 4.0.