Gemini 3.1 Pro Preview Custom Tools
Summary
Gemini 3.1 Pro Preview Custom Tools is a proprietary language model from Google DeepMind, released on 19 Feb 2026. It accepts text, images, video, audio and PDFs and generates text, with a 1M-token context window and up to 66K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $2 per million input tokens and $12 per million output tokens (Gemini API), across 4 providers we track.
Advanced Gemini model for complex reasoning, coding, and multimodal analysis
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | Google DeepMind |
|---|---|
| Release date | 19 Feb 2026 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 1M (1,048,576 tokens) [models.dev] |
| Max output | 66K tokens [models.dev] |
| Knowledge cutoff | Jan 2025 [models.dev] |
| Input | Text, images, video, audio and PDFs [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
| Structured output | Yes [models.dev] |
Gemini 3.1 Pro Preview Custom Tools API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| Gemini API gemini-3.1-pro-preview-customtools | $2 | $12 | $0.20 | 1M | models.dev, 4 Oct 2026 |
| Google Vertex AI gemini-3.1-pro-preview-customtools | $2 | $12 | $0.20 | 1M | models.dev, 4 Oct 2026 |
| Databricks databricks-gemini-3-1-pro | $2 | $12 | $0.20 | 1M | models.dev, 4 Oct 2026 |
| OpenRouter google/gemini-3.1-pro-preview-customtools | $2 | $12 | $0.20 | 1M | OpenRouter, 4 Oct 2026 |
Frequently asked questions
What is the context window of Gemini 3.1 Pro Preview Custom Tools?
Gemini 3.1 Pro Preview Custom Tools has a context window of 1,048,576 tokens (1M) and can generate up to 65,536 tokens in a single response, according to models.dev.
How much does the Gemini 3.1 Pro Preview Custom Tools API cost?
Through Gemini API, Gemini 3.1 Pro Preview Custom Tools costs $2 per million input tokens and $12 per million output tokens. Prices last verified 4 Oct 2026.
Is Gemini 3.1 Pro Preview Custom Tools open source?
No. Gemini 3.1 Pro Preview Custom Tools is a proprietary model; Google DeepMind has not released its weights. It is available through APIs including Gemini API, Google Vertex AI, Databricks, OpenRouter.
When was Gemini 3.1 Pro Preview Custom Tools released?
Google DeepMind released Gemini 3.1 Pro Preview Custom Tools on 19 Feb 2026, according to models.dev.
Which providers offer Gemini 3.1 Pro Preview Custom Tools?
We track Gemini 3.1 Pro Preview Custom Tools on 4 providers: Gemini API, Google Vertex AI, Databricks, OpenRouter.
Change history
No changes detected since we started tracking this model. We re-check every source daily.
Sources
- https://github.com/sst/models.dev/blob/dev/providers/google/models/gemini-3.1-pro-preview-customtools.toml
- https://github.com/sst/models.dev/blob/dev/providers/google-vertex/models/gemini-3.1-pro-preview-customtools.toml
- https://github.com/sst/models.dev/blob/dev/providers/databricks/models/databricks-gemini-3-1-pro.toml
- https://openrouter.ai/google/gemini-3.1-pro-preview-customtools