AI Model Comparison
Side-by-side comparison of pricing, context window, benchmarks, capabilities, and license. Every figure comes from the developer's own pages, last checked on ; each model's page lists its sources. A figure we could not source shows as a dash.
Model A — Anthropic
Claude Fable 5.1 is Anthropic's model for demanding reasoning and long-horizon agentic work, released on September 1, 2026, and extends Claude Fable 5 at the same input and output prices. It takes text and image input, returns text, and uses adaptive thinking that is always on.
Model B — OpenAI
GPT-6 Astra is a reasoning model from OpenAI, released in the API on September 3, 2026, which OpenAI describes as its most capable API model for complex reasoning, coding, computer use, research and document creation. It takes text and image input, returns text, and has an April 30, 2026 knowledge cutoff.
| Property | Claude Fable 5.1 | GPT-6 Astra |
|---|---|---|
| Released | Sep 1, 2026 | Sep 3, 2026 |
| Developer | Anthropic | OpenAI |
| Type | reasoning | reasoning |
| License | proprietary | proprietary |
| Context window | — | 1,050,000 |
| Parameters | — | — |
| Developer status | — | — |
| Input $/M tokens | $10.00 | $10.00 |
| Output $/M tokens | $50.00 | $50.00 |
Bold green values indicate the winner on that dimension where comparison is meaningful (lower price wins; bigger context wins; more open license wins; newer date wins). Prices are the ones each developer lists today; a model it no longer prices has none.
Programmatic access available at /api/ai/compare?a=claude-fable-5-1&b=gpt-6-astra. CORS is open. Citation guidance: /about/editorial-process.