GPT-5.6 Luna | Epoch AI

ECI#19

156

OpenAI

Jul. 9, 2026

Closed weights

GPT-5.6 Luna is a closed-weights model from OpenAI, released July 9, 2026. It has an ECI score of 156 and ranks 19th of 249 tracked models. At the time of its release, it ranked 11th of 230 tracked models.

GPT-5.6 Luna vs select alternatives

Domain	Benchmark	GPT-5.6 Luna OpenAI Jul. 9, 2026 Closed weights	GPT-5.2 Pro OpenAI Dec. 11, 2025 Closed weights	GPT-5.3 Codex OpenAI Feb. 5, 2026 Closed weights	Grok 4.6 xAI Aug. 12, 2026 Closed weights
	ECI scoreBest score 166	156	155	157	156
	Ranking	#19	#23	#15	#17
Conceptual reasoning	ARC-AGI-2Best score 95%	60%	54%	n/a	67%
	ARC-AGI-1Best score 99%	88%	91%	n/a	88%
Games	Chess PuzzlesBest score 72%	40%	n/a	n/a	40%
	Mystery Game PuzzlesBest score 84%	21%	n/a	n/a	34%
Mathematics	FrontierMath Tiers 1-3 (v2)Best score 94%	82%	74%	n/a	66%
	FrontierMath Tier 4 (v2)Best score 98%	61%	46%	n/a	32%
	OTIS Mock AIME 2024-2025Best score 100%	98%	n/a	n/a	99%
Science	GPQA DiamondBest score 96%	92%	n/a	n/a	94%
World knowledge	SimpleQA VerifiedBest score 76%	41%	n/a	n/a	49%

Model metadata

General
Organization	OpenAI
Release date	Jul. 9, 2026
Model accessibility	Closed weights
Country	United States of America
Knowledge cutoff	Unknown
Provider notes	GPT-5.6

Pricing
Input price	$0.20 / 1M tokens
Output price	$1.20 / 1M tokens

Training
Parameters	Unknown
Training compute	Unknown
Training hardware	Unknown
Training time	Unknown
Training dataset size	Unknown