Anthropic's upgraded Mythos-class flagship, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work.
OpenAI's previous frontier model for complex professional workloads, built on GPT-5.4 with stronger reasoning and higher reliability.
No shared demos for these models yet.
No captured outputs for these models yet.
Both Claude Fable 5.1 and GPT 5.5 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 5.5 has a lower blended cost. Claude Fable 5.1: $10.00 input / $50.00 output. GPT 5.5: $5.00 input / $30.00 output.
GPT 5.5 has a larger context window: Claude Fable 5.1 supports 1M tokens vs GPT 5.5 at 1.1M tokens.
Yes, both Claude Fable 5.1 and GPT 5.5 support vision/image input.
Claude Fable 5.1 and GPT 5.5 have similar overall capabilities. The main differences lie in pricing, context window size, and provider-specific strengths. Use this comparison page to review all metrics side by side.
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 Claude Fable 5.1 and GPT 5.5 for free on idapt.app to see which performs better for your specific needs.