Skip to main content
idapt
HomeAI ModelsExploreResourcesPricing
Sign inUse for Free
  • Home
  • Pricing
  • AI Models
  • Skills
  • Image models
  • Voice models
  • Video models
  • Rankings
  • Multi-Model Chat
  • Agents
  • Computers
  • Drive
  • Automations
  • AI Gateway
  • All features →
  • Blog
  • About
  • Comparisons
  • Benchmarks
  • Model Match
  • Demos
  • Help center
  • FAQ
  • Privacy
  • Support
  • Developers
  • Quickstarts
  • API reference
  • API pricing
  • CLI
  • MCP
  • Migrate
  • Downloads
  • Desktop
© idapt[email protected]TermsPrivacy PolicyLegal noticeReport content
X (Twitter)Discord

Step 5 Preview vs Claude Fable 5.1

At a glance

StepFun's flagship agentic model, a 600B-parameter MoE with 27B active.

1M ctx$1.00/$2.70 per M

Anthropic's upgraded Mythos-class flagship, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work.

1M ctx$10.00/$50.00 per M
Demos
All demos

No shared demos for these models yet.

AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:OpenRouter
Cheaper93%
Reasoning & Knowledge
Expert-Level—Factual Recall—
Math
Competition Math—
Agentic
Novel Reasoning—
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
Sources:Epoch AI·OpenRouter· as of 2026-10-02
Reasoning & Knowledge
Expert-Level46.5%Factual Recall70.8%
Math
Competition Math100.0%
Agentic
Novel Reasoning90.0%
Specs
1M
Context
64K
Max output
Oct 2026
Released
1M
Context
128K
Max output
Sep 2026
Released
Capabilities
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Pricing
Live pricing, shown before you run
Input90%$1.00/M tokens
Output95%$2.70/M tokens
Cache read80%$0.05/M tokens
Live pricing, shown before you run
Input$10.00/M tokens
Output$50.00/M tokens
Cache read$0.25/M tokens
Cache write$12.50/M tokens
Web search$0.01/search
Chat with Step 5 PreviewGo to model
Chat with Claude Fable 5.1Go to model
Frequently Asked Questions: Step 5 Preview vs Claude Fable 5.1▼

Which is better, Step 5 Preview or Claude Fable 5.1?

▼

Both Step 5 Preview 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.

Which is cheaper, Step 5 Preview or Claude Fable 5.1?

▼

Step 5 Preview has a lower blended cost. Step 5 Preview: $1.00 input / $2.70 output. Claude Fable 5.1: $10.00 input / $50.00 output.

Which has a larger context window, Step 5 Preview or Claude Fable 5.1?

▼

Step 5 Preview has a larger context window: Step 5 Preview supports 1M tokens vs Claude Fable 5.1 at 1M tokens.

Do both Step 5 Preview and Claude Fable 5.1 support vision?

▼

Yes, both Step 5 Preview and Claude Fable 5.1 support vision/image input.

What are the key differences between Step 5 Preview and Claude Fable 5.1?

▼

Key differences: Step 5 Preview is significantly cheaper. Compare full specs on this page.

Which model should I choose for my use case?

▼

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 Step 5 Preview and Claude Fable 5.1 for free on idapt.app to see which performs better for your specific needs.

Open in App