Gemini 3.1 Pro Preview Custom Tools is a specialised variant of Google's Gemini 3.1 Pro Preview, sharing the same pricing and multimodal input support (text, image, file, audio, video) with a 1M token context window. However, it carries no independent benchmark data of its own, so its performance cannot be assessed separately from the base model.

For businesses, the Custom Tools variant may offer workflow-specific integrations, but without measured benchmarks, there is no reliable basis for preferring it over the standard Gemini 3.1 Pro Preview, which has full benchmark coverage. Teams should default to the benchmarked base model unless the custom tooling provides a specific, documented capability advantage.

Until independent benchmark data is available, this variant should be treated as experimental. Adopt the standard Gemini 3.1 Pro Preview for production use.

Assessed June 6, 2026

Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?