Gemini 3.1 Pro Preview

• 🧠 Google's most advanced reasoning model, built on Gemini 3 Pro.
• 📏 1M-token context spanning text, images, audio, video, code.
• 👁️ Multimodal input: text, image, speech, and video.
• 🔧 Dedicated custom-tools endpoint prioritizes bash and custom functions.
• 📚 Handles PDFs and entire code repositories in context.
• 🏢 Available through Google Cloud's Gemini Enterprise Agent Platform.
• ⚡ Faster than average and fairly concise, per Artificial Analysis.
• 📅 Preview release February 2026, ahead of general availability.

Google

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Gemini 3.1 Pro Preview is the latest iteration of Google's flagship "Pro" frontier line, positioned by Google DeepMind as its most advanced reasoning model for complex, multi-step problems. It comprehends massively multimodal inputs — text, audio, images, video, PDFs, and entire code repositories — within a 1M-token context window, outputting up to roughly 66K tokens. Google states the model is based on its predecessor, Gemini 3 Pro, which launched in November 2025.

According to Google Cloud's documentation, 3.1 Pro exposes a dedicated custom-tools endpoint that prioritizes bash and custom functions such as file viewing and code search, aimed at agentic workflows. It is offered in preview via the Gemini Enterprise Agent Platform, allowing teams to validate the updates before general availability.

Within the broader family, 3.1 Pro is the reasoning-heavy counterpart to the faster Gemini 3.5 Flash and earlier Gemini 3 Flash Preview, which trade some depth for speed. Independent evaluator Artificial Analysis notes the model accepts text, image, speech, and video input, is faster than average and fairly concise, though somewhat expensive relative to similarly priced peers.