LLM Reference

Claude Opus 4.5 vs StepFun Step-2

Claude Opus 4.5 (2025) and StepFun Step-2 (2025) are frontier reasoning models from Anthropic and StepFun. Claude Opus 4.5 ships a 200k-token context window, while StepFun Step-2 ships a 128k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads. It focuses on practical selection signals rather than broad model-family marketing.

Claude Opus 4.5 is safer overall; choose StepFun Step-2 when provider fit matters.

Decision scorecard

Local evidence first
SignalClaude Opus 4.5StepFun Step-2
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsgeneral production evaluation
Decision fitCoding, RAG, and AgentsLong context
Context window200k128k
Cheapest output$25/1M tokens-
Provider routes6 tracked0 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose Claude Opus 4.5 when...
  • Claude Opus 4.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Opus 4.5 has broader tracked provider coverage for fallback and route flexibility.
  • Claude Opus 4.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
  • Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
Choose StepFun Step-2 when...
  • Local decision data tags StepFun Step-2 for Long context.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Claude Opus 4.5

$10,250

Cheapest tracked route/tier: Microsoft Foundry

StepFun Step-2

Unavailable

No complete token price in local provider data

Cost delta unavailable until both models have sourced input and output token prices.

Switch friction

Claude Opus 4.5 -> StepFun Step-2
  • No overlapping tracked provider route is sourced for Claude Opus 4.5 and StepFun Step-2; plan for SDK, billing, or endpoint changes.
  • Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
StepFun Step-2 -> Claude Opus 4.5
  • No overlapping tracked provider route is sourced for StepFun Step-2 and Claude Opus 4.5; plan for SDK, billing, or endpoint changes.
  • Claude Opus 4.5 adds Vision, Multimodal, and Reasoning in local capability data.

Specs

Specification
Released2025-11-012025-10-15
Context window200k128k
Parameters1T (MoE)*
ArchitectureDecoder Only-
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-12-

Pricing and availability

Pricing attributeClaude Opus 4.5StepFun Step-2
Input price$5/1M tokens-
Output price$25/1M tokens-
Providers-

Capabilities

CapabilityClaude Opus 4.5StepFun Step-2
VisionYesNo
MultimodalYesNo
ReasoningYesNo
JSON / Tool useYesNo
Structured outputsYesNo
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

Continue comparing

Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.