Nano Banana Google Search grounding: not a Sume parameter

Grounding with Google Search is a feature of Google's own Gemini image API. Sume's image request has no grounding field, so you cannot switch it on through google/nano-banana-2: a parameter the model does not list returns 400 unsupported_parameter.

Google's feature list is from its image generation page; Sume's rules are from Image generation and editing and the image catalog code, read 2026-09-30.

What does Google document?

The page says the model can use Google Search as a tool to verify facts and generate imagery from real-time data, with examples such as weather maps, stock charts and recent events. It says Gemini 3.1 Flash Image adds Google Image Search grounding alongside web search, and that the Gemini 3.1 Flash Lite Image model does not support Search grounding.

What does Sume list for Nano Banana?

How can I check what a model accepts?

Use the model discovery route, which returns supported_parameters per model; that is the definitive list. If a field is not there, do not send it.

What can I do if my image needs current facts?

Fetch the facts in your own code or agent, put them in the prompt, and then generate. Sume will render what the prompt says; it does not look anything up. For other Nano Banana request rules see the quality parameter.