Anthropic's new flagship for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
StepFun's flagship agentic model, a 600B-parameter MoE with 27B active.
No shared demos for these models yet.
No captured outputs for these models yet.
Both Claude Opus 5.5 and Step 5 Preview 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.
Step 5 Preview has a lower blended cost. Claude Opus 5.5: $4.00 input / $20.00 output. Step 5 Preview: $1.00 input / $2.70 output.
Claude Opus 5.5 has a larger context window: Claude Opus 5.5 supports 1M tokens vs Step 5 Preview at 1M tokens.
Yes, both Claude Opus 5.5 and Step 5 Preview support vision/image input.
Key differences: Step 5 Preview is significantly cheaper. 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 Claude Opus 5.5 and Step 5 Preview for free on idapt.app to see which performs better for your specific needs.