# Gemini Decisions API — fast, calibrated answers to closed-set questions

> A new Gemini API endpoint that scores your options and returns probabilities instead of writing text.

- Org: Google
- Date: 2026-11-11
- Category: model, tool
- Source: https://blog.google/innovation-and-ai/technology/developers-tools/gemini-decisions-api/
- Canonical page: https://ai-tldr.dev/releases/google-gemini-decisions-api/

## In short

Google's Gemini Decisions API runs the new gemini-decision-1 model to score yes/no, multiple-choice and rubric questions in one forward pass, with confidence scores, 150-250 ms latency and $0.10 per 1M input tokens.

## What it is

The Gemini Decisions API is a new Gemini API endpoint for bounded choices such as tool selection, policy checks, model routing and context grading. It is powered by a new model, Gemini Decision 1 (gemini-decision-1), and returns a probability and a confidence score for each answer instead of generated text.

## How it works

You send one input (text, images, audio, video or PDFs) with up to 1,000 independent questions. The model scores the candidate options in a single forward pass. Each question is a yes/no, a choice from 2 to 255 options, or an ordered rubric that returns a weighted score. Google reports 150-250 ms end-to-end latency, nearly flat from 1 to 100 questions.

## Why it matters

Agents often pay for a full generation just to pick a route or pass a safety check. A confidence score lets code send unclear cases to a fallback model or a human. Google says the model is nearly 5x cheaper than Gemini 3.5 Flash-Lite with the Interactions API on its shared benchmark suite, and Google Search already uses it as a safety layer for MCP tools.

## Who it's for

Agent builders and teams running high-volume routing or moderation

## Try it

client.decisions.create(...) with model gemini-decision-1 (genai client, api_version v1beta)

## Quick facts

- Maker: Google DeepMind
- Model: gemini-decision-1
- Input limit: Up to 256K tokens, up to 1,000 questions per request
- Price: $0.10 / 1M input tokens, $0 output
- Availability: Gemini API and Google AI Studio (free tier)
- Question types: Yes/No, multiple choice (2-255 options), ordered rubric

## FAQ

### How much does the Gemini Decisions API cost?

The Gemini Decisions API costs $0.10 per 1M input tokens and $0 for output tokens, according to Google. Input is billed once per request no matter how many questions it carries, and Google lists no separate thinking-token, audio transcription or OCR charges. Google AI Studio offers a no-cost tier for prototyping.

### How many questions can one Decisions API request hold?

One Gemini Decisions API request takes a single multimodal input of up to 256K tokens and up to 1,000 independent questions. Multiple-choice questions can have 2 to 255 options. Google says latency stays nearly flat from 1 to 100 questions per request.

### How does Gemini Decision 1 compare with Gemini 3.5 Flash-Lite?

Google says Gemini Decision 1 is nearly 5x cheaper than Gemini 3.5 Flash-Lite with the Interactions API across a shared suite covering agent routing, reasoning, ranking and multimodal understanding, and that it has the lowest calibration error. The specific scores are published only as images in Google's post.

### Where can I use the Gemini Decisions API today?

The Gemini Decisions API is available in the Gemini API and Google AI Studio, which also has a playground. Google lists OpenRouter, LangChain, Vercel AI SDK, LiteLLM, Pydantic AI, Pipecat and LiveKit as integrations, and says support for Gemini in Google Cloud is coming soon.

## Links

- [Announcement](https://blog.google/innovation-and-ai/technology/developers-tools/gemini-decisions-api/)
- [Decisions API Docs](https://aistudio.google.com/docs/decisions-api)
- [Playground](https://aistudio.google.com/apps/bundled/gemini-decisions-api-playground?fullscreenApplet=true)
- [OpenRouter Listing](https://openrouter.ai/google/gemini-decision-1)