Chat with 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

No signup required — try it as a guest. 30,000 free tokens every day once you sign up.

Provider
Google
Model slug
google/gemini-3.1-pro-preview-customtools
Typical cost
Around 7,800–19,500 tokens per typical message. 15M Pro tokens buy roughly 769–1…
Availability
On Faceb.ai · chat + API

About 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...

What it's good at

1

Very large context window — 1,048,756 tokens (paste entire codebases or long PDFs).

2

Hosted by Google — you can access it here alongside GPT-4o, Claude, Gemini and 100+ more on one plan.

3

Switch to any other model mid-conversation from the picker.

Pricing on Faceb.ai

Around 7,800–19,500 tokens per typical message. 15M Pro tokens buy roughly 769–1,923 messages.

Use Gemini 3.1 Pro Preview Custom Tools from the API

OpenAI-compatible. Same Faceb.ai tokens cover chat and API. Drop-in replacement for the OpenAI SDK.

curl https://api.faceb.ai/v1/chat/completions \
  -H "Authorization: Bearer sk-faceb-YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.1-pro-preview-customtools",
    "messages": [{"role": "user", "content": "Hello!"}],
    "stream": true
  }'
from openai import OpenAI

client = OpenAI(
    base_url="https://api.faceb.ai/v1",
    api_key="sk-faceb-YOUR_KEY",
)

stream = client.chat.completions.create(
    model="google/gemini-3.1-pro-preview-customtools",
    messages=[{"role": "user", "content": "Hello!"}],
    stream=True,
)
for chunk in stream:
    print(chunk.choices[0].delta.content or "", end="", flush=True)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.faceb.ai/v1",
  apiKey: "sk-faceb-YOUR_KEY",
});

const stream = await client.chat.completions.create({
  model: "google/gemini-3.1-pro-preview-customtools",
  messages: [{ role: "user", content: "Hello!" }],
  stream: true,
});
for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content || "");
}

Also works for image generation (image-output model slugs return image_url content parts) and web search (add "web_search": true to the payload). Same endpoint, same wallet.

Full API docs → · Get an API key →

Frequently asked — Gemini 3.1 Pro Preview Custom Tools

What is Gemini 3.1 Pro Preview Custom Tools?

Gemini 3.1 Pro Preview Custom Tools is a chat/completion model served by Google and accessed through Faceb.ai. Try it without signing up — guest users get a small pool of session tokens to experiment.

Is Gemini 3.1 Pro Preview Custom Tools free on Faceb.ai?

You get 30,000 tokens free every day — usually enough for a handful of messages a day on this model. Need more? Pro is $14.99/month for 15M tokens, or top-ups from $5.

What's Gemini 3.1 Pro Preview Custom Tools's context window?

1,048,756 tokens. Paste your source material in, no need to truncate.

Can I call Gemini 3.1 Pro Preview Custom Tools from the API?

Yes. Any API key from /account/api/ works with model slug `google/gemini-3.1-pro-preview-customtools`. The OpenAI SDK works with base_url=https://api.faceb.ai/v1.

How does Gemini 3.1 Pro Preview Custom Tools compare to GPT-4o or Claude?

Depends on the task. Faceb.ai lets you switch models per message — benchmark side-by-side by asking both the same prompt, which is more reliable than abstract comparisons.

How much does Gemini 3.1 Pro Preview Custom Tools cost per message here?

Around 7,800–19,500 tokens per typical message. 15M Pro tokens buy roughly 769–1,923 messages.

Does Faceb.ai train on my Gemini 3.1 Pro Preview Custom Tools prompts?

No. We contractually request that upstream providers not train on content routed through us. Your chat history lives only on your account.

Is Gemini 3.1 Pro Preview Custom Tools good for coding?

It depends on the model size and training mix. For serious code work the developer favourites are Claude 3.5 Sonnet and DeepSeek V3; for quick edits, most capable models work fine.

Can I use Gemini 3.1 Pro Preview Custom Tools on the API with the OpenAI SDK?

Yes — point your SDK at https://api.faceb.ai/v1 and use this model's slug as the model parameter. Everything else works as normal.

Does Gemini 3.1 Pro Preview Custom Tools support image inputs?

Check the model catalog — multimodal models are marked in the picker. If it accepts images, you can drop screenshots and diagrams straight into the chat.

Can I switch from Gemini 3.1 Pro Preview Custom Tools to another model mid-chat?

Yes — the picker is always at the top of the chat. Previous context carries over.

Will newer versions of Gemini 3.1 Pro Preview Custom Tools show up here automatically?

Yes. Our catalog auto-fetches from the upstream aggregator, so provider updates and new versions appear in the picker as soon as they're available.

Or try a different model

Your Faceb.ai tokens work for every model — switch per message, no extra subscriptions.

Ready to chat?

One subscription covers every frontier model — switch between them per message. No extra API keys, no extra bills.

Start chatting with Gemini 3.1 Pro Preview Custom Tools → Go Pro · $14.99/mo