Gemini 3.1 Pro Preview Custom Tools: Pricing, Context Window & Benchmarks
by Google
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 or user-defined functions are available. This specialized preview endpoint significantly increases function calling reliability and ensures the model selects the most appropriate tool in coding agents and complex, multi-tool workflows. It retains the core strengths of Gemini 3.1 Pro, including multimodal reasoning across text, image, video, audio, and code, a 1M-token context window, and strong software engineering performance.
What you can do with Gemini 3.1 Pro Preview Custom Tools
Everyday Q&A and clear explanations
Writing help (emails, posts, summaries)
Idea generation and brainstorming
Learning support with step-by-step guidance
Benchmarks not available
This model isn't listed on Artificial Analysis yet. Showing OpenRouter specs below.
| Metric | Value |
|---|---|
| Provider | |
| Context Window | 1,048,576 tokens |
| Input Price | $2.00/1M tokens |
| Output Price | $12.00/1M tokens |
| Release Date | Feb 25, 2026 |
| Modalities | text, audio, image, video, file |
| Capabilities | Vision, Audio Input |
Compare Gemini 3.1 Pro Preview Custom Tools to other models
See how it stacks up on price, quality, and overall performance.
Frequently asked questions
What is Gemini 3.1 Pro Preview Custom Tools good for?
Use Gemini 3.1 Pro Preview Custom Tools for everyday tasks like writing, summarizing, brainstorming, and getting clear explanations.
How much does Gemini 3.1 Pro Preview Custom Tools cost?
Pricing is based on usage. Current rates are $2.00/1M tokens for input and $12.00/1M tokens for output.
Can I try Gemini 3.1 Pro Preview Custom Tools for free?
Yes. You can start a chat instantly and test the model before deciding on a plan.
Does Gemini 3.1 Pro Preview Custom Tools support images or audio?
Gemini 3.1 Pro Preview Custom Tools can understand images.
Similar models
Pricing, context, and capability data are sourced from OpenRouter.
Compare Models
Select a model to compare with Gemini 3.1 Pro Preview Custom Tools