Model capability probe

Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview) | JSON mode

Whether Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview) supports JSON mode cannot be decided from the name alone. Check model ID google/gemini-3.1-flash-image-preview, provider Google, catalog params, modality, a lightweight runtime probe, and the error body together.

Model

google/gemini-3.1-flash-image-preview

Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview)

Provider

Google

32 models in catalog

Capability

JSON mode

json-mode

Catalog signal

catalog shows support

Context: 65,536

Capability probe summary

Model

google/gemini-3.1-flash-image-preview

Capability

json-mode

Catalog signal

catalog shows support

Read-only check. Detection data burns after 5 minutes.

How to judge this capability

Whether Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview) supports JSON mode cannot be decided from the name alone. Check model ID google/gemini-3.1-flash-image-preview, provider Google, catalog params, modality, a lightweight runtime probe, and the error body together.

Model: google/gemini-3.1-flash-image-preview
Provider: Google
Capability: JSON mode

How to prove it during checking

Read-only check. Detection data burns after 5 minutes.

Start with the catalog signal: catalog shows support, then verify with a real key in read-only mode.
The capability probe must bind model ID google/gemini-3.1-flash-image-preview; do not test another model from the same provider.
JSON mode · supports include_reasoning · supports max_tokens · supports reasoning · supports response_format

Next action

Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview) JSON mode should turn into an operator action: confirm sale tags, fill the capability matrix, change route, suggest a fallback model, or mark unsupported for now.

Read-only check. Detection data burns after 5 minutes.
Catalog signal: catalog shows support
Context: 65,536

Open key checker

Read-only check. Detection data burns after 5 minutes.

Open models

Google: Nano Banana 2 (Gemini 3.1 Flash Image Preview)

Open providers

Google