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 or user-defined functions are available. This specialized preview endpoint significantly increases function calling reliability and ensures the model selects the most appropriate tool in coding agents and complex, multi-tool workflows.

It retains the core strengths of Gemini 3.1 Pro, including multimodal reasoning across text, image, video, audio, and code, a 1M-token context window, and strong software engineering performance.

google/gemini-3.1-pro-preview-customtools

Organization: Google
Family: gemini-pro
Providers: 10
Context: 1,048,576
Output limit: 65,536
Knowledge: 2025-01
Release: 2026-02-19
Updated: 2026-02-19
Weights: Closed
Input: text, image, video, audio, pdf
Output: text
Capabilities: Tools, Reasoning, Structured, Temperature

Providers

Compare every cataloged offer for this model, including its provider, route, token limits, price, and capabilities.

10 offers · USD per million tokens

Provider	Model ID	Context	Output	Input / output · 1M	Reasoning	Tools	Structured	Details
Databricks	databricks-gemini-3-1-pro	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Eden AI	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Kilo Gateway	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Merge Gateway	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
NanoGPT	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Neon	gemini-3-1-pro	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Google AI Studiovia OpenRouter	google/gemini-3.1-pro-preview-customtools unknown	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
OrcaRouter	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Tempr Gateway	google/gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View
Vertex	gemini-3.1-pro-preview-customtools	1,048,576	65,536	$2.00 / $12.00	Yes	Yes	Yes	View

Prices and limits apply to each offer. A dash means the value is not provided. OpenRouter offers show the hosting provider and routing channel separately.

Pricing

Compare token rates and cache charges across available routes and hosting configurations.

USD per million tokens

Input from$2.00Per 1M input tokens

Output from$12.00Per 1M output tokens

Available offers10Across 10 providers

Lowest listed input and output prices across the offers above; they may belong to different providers. These are base rates, before conditional pricing, discounts or additional fees.

Endpoint price comparisonLatest observed snapshot · 1 lowest-priced configuration

InputOutput

Google AI Studiogoogle-ai-studio

$2.00$12.00

google/gemini-3.1-pro-preview-customtoolsObserved Oct 4, 2026, 11:31 AM UTC

Input: $2.00
Output: $12.00
Cache read: $0.20
Cache write: $0.375

Additional fees and pricing conditions

audio: $0.000002 / audio token
image: $0.000002 / image
web search: $0.014 / search
input audio cache: $0.0000002 / audio token
internal reasoning: $0.000012 / reasoning token

overrides · USD per token for token prices; time windows use UTC.

[
  {
    "audio": "0.000004",
    "prompt": "0.000004",
    "completion": "0.000018",
    "input_cache_read": "0.0000004",
    "input_audio_cache": "0.0000004",
    "min_prompt_tokens": 200000
  }
]

Hosting prices through OpenRouter All endpoints and cache rates

Endpoint	Input / 1M	Output / 1M	Cache read / 1M	Cache write / 1M
Google AI Studiogoogle-ai-studio	$2.00	$12.00	$0.20	$0.375

Each row is a hosting configuration. Open an offer in Providers for its full pricing conditions and additional fees. Endpoint observations may differ from the routing catalog's base price.

Performance

Review reported latency and output-throughput percentiles from the latest observed rolling window.

Latest 30-minute observation

Time to first token · milliseconds

Latency distributionRolling 30-minute snapshot · 1 endpoint

P50P75P90P99

Google AI Studiogoogle-ai-studio

2,501.5–30,018.87 ms

All latency percentiles 1 endpoints

Endpoint	P50	P75	P90	P99
Google AI Studiogoogle-ai-studio	2,501.5 ms	3,343.75 ms	4,352.8 ms	30,018.87 ms

Output throughput · tokens per second

Throughput distributionRolling 30-minute snapshot · 1 endpoint

P50P75P90P99

Google AI Studiogoogle-ai-studio

66.5–140.6 t/s

All throughput percentiles 1 endpoints

Endpoint	P50	P75	P90	P99
Google AI Studiogoogle-ai-studio	66.5 t/s	98.5 t/s	112.5 t/s	140.6 t/s

Percentiles describe the observed request distribution. These are snapshots of a rolling window, not a historical time series.

Uptime

Compare successful request rates across the latest 5-minute, 30-minute, and 24-hour observations.

Successful requests by window

Availability by endpointCurrent overlapping windows · 1 endpoint

Endpoint5 minutes30 minutes24 hours

Google AI Studiogoogle-ai-studioObserved Oct 4, 2026, 11:31 AM UTC

—

99.98%

Reported by OpenRouter at the time of collection; rate-limited requests are excluded. A dash means no measurement was reported. This is not a live availability check.

Technical details & API

Explore specifications, supported parameters, reasoning controls, and API identifiers for each OpenRouter route.

Current route specifications

google/gemini-3.1-pro-preview-customtoolsObserved Oct 4, 2026, 11:31 AM UTC

Context: 1,048,576
Maximum output: 65,536
Tokenizer: Gemini
Input: text, audio, image, video, file
Output: text
Moderation: No
Added to OpenRouter: 2026-02-25

Base URLhttps://openrouter.ai/api/v1

Model IDgoogle/gemini-3.1-pro-preview-customtools

Version IDgoogle/gemini-3.1-pro-preview-customtools-20260219

Reasoning

Required: Yes
Enabled by default: Not reported
Default effort: medium
Supported efforts: high, medium, low

Supported parameters

include_reasoning
max_tokens
reasoning
reasoning_effort
response_format
seed
structured_outputs
temperature
tool_choice
tools
top_p

Frequently asked questions

Answers based on the model metadata and serving offers currently in the catalog.

How much does Gemini 3.1 Pro Preview Custom Tools cost?

Listed rates start at $2.00 per million input tokens and $12.00 per million output tokens. Prices vary by provider and configuration; see Pricing for details.

Which providers offer Gemini 3.1 Pro Preview Custom Tools?

There are 10 cataloged offers across 10 providers. Compare model IDs, prices and limits in Providers.

What is the context window?

The cataloged model context is 1,048,576 tokens. Each serving endpoint may apply a different limit.

Does it support tools and structured output?

Tool calling: Yes. Structured output: Yes. Support can vary by endpoint.

Catalog history · 2 recorded revisions

Metadata observations since this model was first cataloged. These are not model release versions.

Sep 14, 2026 · b3802a715020
Sep 12, 2026 · e2fa347e6bb4