# 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 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.

## Model Information

- **Organization**: [google](/llm.txt)
- **Slug**: gemini-3-1-pro-preview-customtools
- **Available at Providers**: 7
- **Release Date**: February 25, 2026

## Providers

| Provider | Name | $ Input (per 1M) | $ Output (per 1M) | Free | Link |
|----------|------|-----------------|------------------|------|------|
| [Google Vertex AI](/llm/googlevertex.txt) | Gemini 3.1 Pro Preview Custom Tools | 2.00 | 12.00 |  |  |
| [Google Gemini](/llm/gemini.txt) | Gemini 3.1 Pro Preview Custom Tools | 2.00 | 12.00 |  |  |
| [AIHubMix](/llm/aihubmix.txt) | gemini-3.1-pro-preview-customtools | 2.00 | 12.00 |  | [View](https://aihubmix.com/model/gemini-3.1-pro-preview-customtools) |
| [ApiYI](/llm/apiyi.txt) | gemini-3.1-pro-preview-customtools |  |  |  |  |
| [Kilo Code](/llm/kilocode.txt) | Google: Gemini 3.1 Pro Preview Custom Tools | 2.00 | 12.00 |  | [View](https://kilo.ai/models/google/gemini-3.1-pro-preview-customtools) |
| [OpenRouter](/llm/openrouter.txt) | Gemini 3.1 Pro Preview Custom Tools | 2.00 | 12.00 |  | [View](https://openrouter.ai/google/gemini-3.1-pro-preview-customtools-20260219) |
| [Writingmate](/llm/writingmate.txt) | Google: Gemini 3.1 Pro Preview Custom Tools |  |  |  | [View](https://writingmate.ai/models/google/gemini-3.1-pro-preview-customtools) |

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