---
id: "google/gemini-3.1-pro-preview-customtools"
also: ["google/gemini-3.1-pro-preview-customtools-20260219"]
cheapest_list_usd_per_m: "2.0 in, 12.0 out, at google-ai-studio on openrouter"
cheapest_effective_usd_per_m: "1.0957 in, 12.0 out, at google-ai-studio on openrouter"
context: 1048576
max_output: 65536
input: ["text", "audio", "image", "video", "file"]
output: ["text"]
released: "2026-02-25"
reasoning: ["high", "medium", "low"]
api: ["/api/v1/chat/completions", "/api/v1/completions", "/api/v1/messages", "/api/v1/responses"]
params: ["include_reasoning", "max_tokens", "reasoning", "reasoning_effort", "response_format", "seed", "structured_outputs", "temperature", "tool_choice", "tools", "top_p"]
endpoints: 1
gateways: "openrouter (1)"
no_training: 1
trains: 0
retains_prompts: 1
---
# Google: 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...