GPT-5.6 Sol

Name: GPT-5.6 Sol
Author: OpenAI

Restricted

OpenAI's GPT-5.6 flagship, available in limited preview through the OpenAI API and Codex for approved organizations.

Publisher: OpenAI
Family: GPT
Context: 1.1M
Input
Output
Providers: openai
Released: 26 Jun 2026

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Notes

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Attribution

Benchmark scores: AA Vals AI EQ-Bench Lech Mazur

Attribution policy →

Context

1.1M

Weights

Closed

API only

Input

/1M tok

Output

$20

/1M tok

Blended

#472/ 494/1M · 3:1

Speed

#103/ 493tok/s

Cache read

$0.20

0.05x input

Cache write

$2.50

0.63x input

Price & speed via Artificial Analysis · ranked across tracked models · caching via OpenRouter

Reasoning effort	Index	Speed
max	47.0	0 t/s
xhigh	44.0	0 t/s
high	42.3	0 t/s
medium	39.2	0 t/s
low	33.5	0 t/s
Non-reasoning	28.3	0 t/s

Intelligence Index per reasoning-effort setting, via Artificial Analysis · pricing identical across tiers

Reported on 21 evals across 12 domains - best 94.1% on GPQA Diamond · #4 of 511

Reported eval scores

Terminal-Bench (Hard)65.9

IFBench72.7

GPQA Diamond94.1

SciCode47.1

Humanity's Last Exam (HLE)49.5

Vals Index58

SAGE52.6

EQ-Bench Creative Writing v31971.6

EQ-Bench Longform Creative Writing81.7

Creative Story-Writing Benchmark83

Vals Multimodal Index72.6

ProofBench83

Vibe Code Bench v1.180.5

τ²-bench (Tau²-bench)85.1

TaxEval v274.8

CorpFin v264.4

MortgageTax67.3

Finance Agent (v2)53.8

EQ-Bench 41250.3

MedScribe85.2