Closest alternatives
On price, GPT-5.6 Sol is 2.5x cheaper per input token and ties GPT-6: Astra on the independent Intelligence Index at 61. On capability at the same price, Claude Fable 5.1 currently leads both independent Artificial Analysis composites. Claude Opus 5 is half the price but has no directly comparable published benchmark against Astra.
| Model | Input $/1M | Output $/1M | Context | AA Intelligence Index |
|---|---|---|---|---|
| GPT-5.6 Sol | $4.00 | $20.00 | not published at this size | 61 |
| Claude Fable 5.1 | $10.00 | $50.00 | 1,000,000 | 66 |
| Claude Opus 5 | $5.00 | $25.00 | 1,000,000 | not published |
When not to switch
If your workload needs GPT-6: Astra's 1,050,000-token context ceiling, its specific strengths (FrontierMath, ExploitBench, BenchCAD), or its improved hallucination rate at maximum reasoning effort relative to GPT-5.6 Sol, the alternatives above do not match those specific numbers.
Ready to test the workflow?
Create account & add creditsWhen to switch
If your workload is cost-sensitive and does not depend on Astra's specific frontier strengths, GPT-5.6 Sol delivers a tied Intelligence Index score at 2.5x less per token. If independent coding and intelligence composites are the deciding factor and price parity is acceptable, Claude Fable 5.1 currently scores higher on both.
Frequently asked questions
What are the alternatives to GPT-6: Astra?
GPT-5.6 Sol costs 2.5x less per input token and ties GPT-6: Astra's Intelligence Index score of 61. Claude Fable 5.1 costs the same and currently scores higher on both independent Artificial Analysis composites. Claude Opus 5 costs half as much but has no directly comparable published benchmark against Astra.
Put GPT-6: Astra to work
Fund a controlled evaluation, start with a prepared prompt, and measure quality and cost on your own workload.