Gemini 3.1 Pro Preview Custom Tools vs Step 3.5 Flash
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Gemini 3.1 Pro Preview Custom Tools and Step 3.5 Flash.
Gemini 3.1 Pro Preview Custom Tools
Gemini 3.1 Pro Preview Custom Tools is a variant of Gemini 3.1 Pro that improves tool selection behavior by preventing overuse of a general bash tool when more efficient third-party...
Step 3.5 Flash
Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....
Technical Specifications
| Specification | Gemini 3.1 Pro Preview Custom Tools | Step 3.5 Flash |
|---|---|---|
| Provider | StepFun | |
| Context Window | 1,048,756 tokens | 262,144 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2026-02-25 | 2026-01-29 |
API Pricing Comparison
Input Price per Million Tokens
Gemini 3.1 Pro Preview Custom Tools
$2.00
Step 3.5 Flash
$0.10
Output Price per Million Tokens
Gemini 3.1 Pro Preview Custom Tools
$12.00
Step 3.5 Flash
$0.30
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Gemini 3.1 Pro Preview Custom Tools Quirks & Gotchas
No developer gotchas reported.
Step 3.5 Flash Quirks & Gotchas
No developer gotchas reported.