WhichAI / Models / GPT-5.6 Sol

GPT-5.6 Sol

· verified September 8, 2026

public paid api in Generator reasoning agents coding

Provider

Statuspublic

AA Intelligence Index58.9 (September 8, 2026 snapshot)

Released2026-07-09

Context window1M

Modalitiesn/a

API price $/1M (in / out)$5 / $30

Speedup to 750 tok/s (Cerebras)

AccessReleased July 9, 2026 (rolling out) · API $5/$30 per 1M tokens · up to 750 tok/s on Cerebras

In one line

OpenAI's July flagship: max reasoning effort, programmatic tool calling and an 'ultra mode' that spins up subagents. Since GPT-6 Astra arrived at double the output price, Sol is the better-value half of OpenAI's line for agentic work.

Coding91

Reasoning93

Writing82

Agents & tools93

Category scores (0-100) are WhichAI blended ratings: public category leaderboards plus editorial judgment. Guidance, not official measurements.

Alternatives worth a look

Gemini 3.8 Flash (Google) · AA 58.7Released September 2, 2026 · API $0.75/$3.75 per 1M tokens ($0.075 cached) · free-tier availability not confirmed
GLM-5.3 (Z.ai) · AA 59.5Released August 14, 2026 · staged access · open weights NOT released at launch (unlike every previous GLM) · API price not published
Kimi K3 (Moonshot AI) · AA 59.7API $3/$15 per 1M tokens ($0.30 cached) · free kimi.com chat · open weights on Hugging Face (July 27, Modified MIT)

Head-to-head: GPT-5.6 Sol vs Claude Opus 5 · GPT-5.6 Sol vs Claude Fable 5 · GPT-5.6 Sol vs Kimi K3

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Artificial Analysis Intelligence Index, 2026 rebased scale (top models ~ 55-66). Snapshot: September 4, 2026 (BenchLM mirror), retrieved September 8, 2026. Specs and prices come from the OpenRouter public model list on the same date. Models nobody has measured carry no index score at all and never enter a ranking: where an estimate exists it is shown separately and labelled unmeasured. Context, price, modality and release dates come from the public OpenRouter model list (retrieved September 8, 2026) and vendor pages. Missing values are not published or not yet verified - shown as -. Sources are linked inside the app (Model guide and About > Methodology).