What is Gemini 3.1 Pro Preview Custom Tools API?
Gemini 3.1 Pro Preview Custom Tools is available through AIMLAPI.
Technical Specifications
- Supported inputs: Image, Text
- Output: Text
- Context window: 1,048,756 tokens / Max output: 65,536 tokens
- Endpoint: /chat/completions
Performance Benchmarks
[embed]
Gemini 3.1 Pro Preview Custom Tools API Pricing
- Input: $2.6 / 1M tokens
- Output: $15.6 / 1M tokens
Where to Use Gemini 3.1 Pro Preview Custom Tools
Coding and code review
Generate, debug, and review code across languages, reading whole files or repos in a single prompt.
Agentic and multi-step workflows
Reliable tool-calling and instruction-following suit agent loops that plan, call tools, and iterate.
Complex reasoning
Extended reasoning improves reliability on multi-step math, logic, and technical analysis.
Long-document analysis
Summarize and extract from contracts, papers, and reports without aggressive chunking.
Code Sample
[embed]
Measured on the AI/ML API gateway across live traffic. Figures are medians unless stated. Last updated 2026-10-12.
Gemini 3.1 Pro Preview Custom Tools is suited to agentic workflows that use custom tools and bash, especially when the model should prioritize registered custom tools like file or code-search tools.
It is documented as a good fit for AI coding assistants that rely on structured tools such as file viewing and editing, rather than defaulting to bash.
It is also suited to DevOps agents that need to call CI/CD systems through tools, as well as MCP workflows that orchestrate multi-step tool-based processes.
Another documented use case is agent applications that require permission-controlled tools and structured logging for auditing or compliance.
import requests r = requests.post( "https://api.aimlapi.com/v1/chat/completions", headers={"Authorization": "Bearer " + AIMLAPI_KEY}, json={ "model": "google/gemini-3.1-pro-preview-customtools", "messages": [ { "role": "user", "content": "Hello!" } ] }, ) print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", { method: "POST", headers: { Authorization: `Bearer ${process.env.AIMLAPI_KEY}`, "Content-Type": "application/json", }, body: JSON.stringify({ "model": "google/gemini-3.1-pro-preview-customtools", "messages": [ { "role": "user", "content": "Hello!" } ] }), }); console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \ -H "Authorization: Bearer $AIMLAPI_KEY" \ -H "Content-Type: application/json" \ -d '{"model":"google/gemini-3.1-pro-preview-customtools","messages":[{"role":"user","content":"Hello!"}]}'
OpenAI-compatible — swap the base URL and it works with your existing SDK.
| Type | Price |
|---|---|
| Input | |
| Output | |
| Cached input |
| Model | Input | Output | Context | Best for |
|---|---|---|---|---|
Gemini 3.1 Pro Preview Custom Tools This page | Reasoning + agents | |||
| Reasoning + agents | ||||
| Balanced coding + agents | ||||
| Long-context, multimodal & agentic workflows | ||||
| Reasoning + agents |
Gemini 3.1 Pro Preview Custom Tools has a 1,048,756 tokens context window and can return up to 65,536 tokens.
Gemini 3.1 Pro Preview Custom Tools takes image, text as input and returns text.
Use google/gemini-3.1-pro-preview-customtools as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.
Gemini 3.1 Pro Preview Custom Tools is priced at input $2.7508 / 1M tokens, output $16.5048 / 1M tokens, cached input $0.27508 / 1M tokens.
Yes, Gemini 3.1 Pro Preview Custom Tools can stream responses as they are generated.
Yes, Gemini 3.1 Pro Preview Custom Tools accepts image input alongside text.
Gemini 3.1 Pro Preview Custom Tools was built by Google.
It supports function calling, reasoning, structured outputs, web search, and parallel tool calls, making it suited for tasks that combine multi-step reasoning with tool use.
