Claude Sonnet 4.5 vs Gemini 3.1 Pro Preview Custom Tools
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 Claude Sonnet 4.5 and Gemini 3.1 Pro Preview Custom Tools.
Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with...
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...
Technical Specifications
| Specification | Claude Sonnet 4.5 | Gemini 3.1 Pro Preview Custom Tools |
|---|---|---|
| Provider | Anthropic | |
| Context Window | 1,000,000 tokens | 1,048,756 tokens |
| Agent Suitability | 91/100 | N/A |
| Time to First Token (TTFT) | 380 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | beta |
| API Available | Yes | Yes |
| Released Date | 2025-09-29 | 2026-02-25 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
Gemini 3.1 Pro Preview Custom Tools
$2.00
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
Gemini 3.1 Pro Preview Custom Tools
$12.00
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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.
Claude Sonnet 4.5 Quirks & Gotchas
- ▸Excellent for long-form writing and nuanced document analysis
- ▸Slightly slower than Sonnet 4.6 — upgrade for production agentic use
Gemini 3.1 Pro Preview Custom Tools Quirks & Gotchas
No developer gotchas reported.