Gemini 3.1 Pro Preview Custom Tools
by GoogleReleased Feb 25, 2026
google/gemini-3.1-pro-preview-customtools- Reads images
- Reads files and PDFs
- Hears audio
- Calls 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...
- Input / 1M tokens
- $2.40
- Output / 1M tokens
- $14.40
- Context
- 1.05M
- Longest answer
- 66K
What it costs
What each call is charged to the token's AI credit.
| Billed for | You pay |
|---|---|
| Input tokens | $2.40 / 1M |
| Output tokens | $14.40 / 1M |
| Cached input, read | $0.24 / 1M |
| Cached input, written | $0.45 / 1M |
| Each input image | $0.000002 |
| Each web search | $0.02 |
| Prompts over 200,000 tokens | $4.80 in, $21.60 out |
A typical call
A short chat turn: 2,000 tokens in, 500 out.
- per call
- $0.01
- calls per $20
- 1,666
What it can do
From its listing. The router passes every field through.
- Reads imagesYes
- Reads files and PDFsYes
- Hears audioYes
- Calls toolsYes
- Answers in a JSON schemaYes
- Reasons before it answersYes
- Searches the webYes
- Caches long promptsYes
- Draws imagesNo
Call it
Any router key works, in the format your SDK already speaks.
import OpenAI from "openai";const ai = new OpenAI({ baseURL: "https://relayfor.si/api/v1", apiKey: process.env.RELAYFOR_ROUTER_KEY,});const reply = await ai.chat.completions.create({ model: "google/gemini-3.1-pro-preview-customtools", messages: [{ role: "user", content: "Welcome the 1,000th holder in one line." }],});Specifications
What its maker and providers list for it.
- Reads
- Text, Audio, Images, Video, and Files
- Writes
- Text
- Context
- 1,048,576 tokens
- Longest answer
- 65,536 tokens
- Reasoning effort
- low to high
- Released
- Feb 25, 2026
- Moderation
- None
Request fields
The fields its providers accept, passed through as you send them.
- include_reasoning
- max_tokens
- reasoning
- reasoning_effort
- response_format
- seed
- structured_outputs
- temperature
- tool_choice
- tools
- top_p
Questions
How much does Gemini 3.1 Pro Preview Custom Tools cost?
$2.40 per million input tokens and $14.40 per million output tokens, paid from the token's AI credit. A call of 2,000 tokens in and 500 out costs about $0.01.
How do I call Gemini 3.1 Pro Preview Custom Tools?
Make a router key for one of your tokens on the dashboard, point any OpenAI or Anthropic SDK at https://relayfor.si/api/v1 and send the model id google/gemini-3.1-pro-preview-customtools. The token's AI credit pays for each call.
How long a prompt can Gemini 3.1 Pro Preview Custom Tools take?
Up to 1,048,576 tokens of context, and up to 65,536 tokens in one answer.
Are my prompts stored?
No. The RFS Router passes each call through and keeps only its token counts and cost, for the token's usage page.
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