Fastest and cheapest model in the GPT-4.1 series for low-latency applications.
Anthropic's upgraded Mythos-class flagship, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work.
No shared demos for these models yet.
No captured outputs for these models yet.
Both GPT 4.1 Nano and Claude Fable 5.1 are capable AI models. The best choice depends on your specific use case: consider pricing, context window, speed, and which capabilities (vision, reasoning, audio) you need.
GPT 4.1 Nano has a lower blended cost. GPT 4.1 Nano: $0.10 input / $0.40 output. Claude Fable 5.1: $10.00 input / $50.00 output.
GPT 4.1 Nano has a larger context window: GPT 4.1 Nano supports 1M tokens vs Claude Fable 5.1 at 1M tokens.
Yes, both GPT 4.1 Nano and Claude Fable 5.1 support vision/image input.
Key differences: GPT 4.1 Nano is significantly cheaper; only Claude Fable 5.1 offers extended reasoning mode. Compare full specs on this page.
If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both GPT 4.1 Nano and Claude Fable 5.1 for free on idapt.app to see which performs better for your specific needs.