feat(go/plugins/googlegenai): Add Gemini 3.1 Flash preview models#5179
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Registers gemini-3.1-flash-lite-preview and gemini-3.1-flash-image-preview on both the GoogleAI and VertexAI backends with Multimodal capability and ModelStageUnstable. Extends the imagen-gemini sample with a VertexAI config detector, two generate helpers, and four flows that exercise the new models on each backend.
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This pull request introduces support for Gemini 3.1 Flash Lite and Image preview models in the Google AI and Vertex AI plugins. It also updates the imagen-gemini sample to include new flows demonstrating these models, along with logic to conditionally initialize the Vertex AI plugin based on environment configuration. I have no feedback to provide.
…ngLevel ThinkingBudget is deprecated for Gemini 3.x per Google's docs; the preferred API is ThinkingLevel. ThinkingLevelMinimal preserves the "fastest, cheapest" intent that ThinkingBudget=0 was expressing.
…Global-only preview models
Ehesp
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Apr 28, 2026
apascal07
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May 5, 2026
apascal07
approved these changes
May 5, 2026
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Adds the two Gemini 3.1 preview models on both backends:
gemini-3.1-flash-lite-previewgemini-3.1-flash-image-previewRegistered as Multimodal /
ModelStageUnstableon GoogleAI and VertexAI. Also extends theimagen-geminisample with two generate helpers (text-only and image+caption) and four flows exercising both models on each backend, gated by ahasVertexAIConfig()check so GoogleAI-only environments still run.Closes the four
gemini-3.1-flash-*-previewrows on the Go parity tracker.Test plan
go test ./plugins/googlegenai/...go build ./samples/imagen-gemini/...GEMINI_API_KEY(and optionallyGOOGLE_CLOUD_PROJECT/GOOGLE_CLOUD_LOCATION) and invoke the four new flows from the dev UI.Evidence of manual testing:
gemini31LiteGoogleAIFlow