Gemini 3.1 Pro Preview Custom Tools
GoogleReleased Feb 25, 2026
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...
- Context window
- 1.0M tokens
- Max output
- 66K tokens
- Input
- text, audio, image, video, file
- Output
- text
- Tokenizer
- Gemini
- Released
- Feb 25, 2026
- Reasoning
- always on
Pricing
Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.
| Per 1M tokens | Provider | + 3% fee | You pay |
|---|---|---|---|
| Input | $2.00 | $0.060 | $2.06 |
| Output | $12.00 | $0.360 | $12.36 |
| Cache read | $0.200 | $0.0060 | $0.206 |
| Cache write | $0.375 | $0.011 | $0.386 |
Supported parameters
- include_reasoning
- max_tokens
- reasoning
- response_format
- seed
- structured_outputs
- temperature
- tool_choice
- tools
- top_p
Call it
OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model google/gemini-3.1-pro-preview-customtools.
curl https://api.openkey.ai/v1/chat/completions \
-H "Authorization: Bearer $OPENKEY_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "google/gemini-3.1-pro-preview-customtools",
"messages": [{"role": "user", "content": "Hello"}]
}'import os
from openai import OpenAI
client = OpenAI(
base_url="https://api.openkey.ai/v1",
api_key=os.environ["OPENKEY_API_KEY"],
)
completion = client.chat.completions.create(
model="google/gemini-3.1-pro-preview-customtools",
messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.openkey.ai/v1",
apiKey: process.env.OPENKEY_API_KEY,
});
const completion = await client.chat.completions.create({
model: "google/gemini-3.1-pro-preview-customtools",
messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);Questions
- How much does Gemini 3.1 Pro Preview Custom Tools cost via API?
- Through OpenKey, Gemini 3.1 Pro Preview Custom Tools costs $2.06 per 1M input tokens and $12.36 per 1M output tokens. That is the provider price ($2.00 / $12.00) plus a flat 3% fee — nothing else.
- What is Gemini 3.1 Pro Preview Custom Tools's context window?
- Gemini 3.1 Pro Preview Custom Tools accepts up to 1.0M tokens of context and returns up to 66K tokens per request.
- Is Gemini 3.1 Pro Preview Custom Tools OpenAI-compatible?
- Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "google/gemini-3.1-pro-preview-customtools" using any OpenAI SDK — only the base URL and API key change.
- What inputs does Gemini 3.1 Pro Preview Custom Tools support?
- Gemini 3.1 Pro Preview Custom Tools accepts text, audio, image, video, file input and produces text output.
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