Claude Fable 5 vs GPT 5.6 Sol vs Grok 4.20 beta 0309 Reasoning

Claude Fable 5 vs GPT 5.6 Sol vs Grok 4.20 beta 0309 Reasoning: Grok 4.20 beta 0309 Reasoning is the cheapest by 87%. Claude Fable 5 (Azure AI Foundry, 1,000,000 ctx); GPT 5.6 Sol (Azure OpenAI, 1,050,000 ctx); Grok 4.20 beta 0309 Reasoning (xAI, 2,000,000 ctx). Route any of them via Agent Command Center for shadow A/B without code changes.

Claude Fable 5 GPT 5.6 Sol Grok 4.20 beta 0309 Reasoning
xAI
Input price$10.00/M$5.00/M$2.00/M
Output price$50.00/M$30.00/M$6.00/M
Context window1,000,0001,050,0002,000,000
Max output128,000128,0002,000,000
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verifiedAug 6, 2026Aug 6, 2026Aug 6, 2026
Cheaper option
~87% cheaper than the priciest in this trio
Larger context
2,000,000 tokens
More capabilities
5 of 6 capability flags advertised

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