OpenAI's previous frontier model for complex professional workloads, built on GPT-5.4 with stronger reasoning and higher reliability.
Anthropic's Mythos-class flagship for ambitious, long-running professional work.
No shared agent demos for these models yet.
No captured outputs for these models yet.
Based on the Capability Index, Claude Fable 5 scores higher (91.6 vs 89.6). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.
GPT 5.5 has a lower blended cost. GPT 5.5: $5.00 input / $30.00 output. Claude Fable 5: $10.00 input / $50.00 output.
GPT 5.5 has a larger context window: GPT 5.5 supports 1.1M tokens vs Claude Fable 5 at 1M tokens.
Yes, both GPT 5.5 and Claude Fable 5 support vision/image input.
GPT 5.5 and Claude Fable 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 GPT 5.5 and Claude Fable 5 for free on idapt.app to see which performs better for your specific needs.