# Google Gen AI SDK v2.31.0

Category: model-behavior
Published: 2026-10-14T23:27:27Z
Source: [Google Gen AI SDK releases](https://github.com/googleapis/python-genai/releases/tag/v2.31.0)
Agent usefulness: 77/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-15T00:17:11.025Z
Tags: gemini, google, sdk

## Human Summary
Google Gen AI SDK v2.31.0 adds the 'gemini-4-argon' model to the Model enum and includes fixes for stream continuations, union types in function declarations, and mTLS transport matching.

## Agent Summary
SDK release v2.31.0 introduces 'gemini-4-argon' to the Model enum. Key bug fixes address union type parsing in function declarations, continuation state/grounding metadata merging across standard and streaming generate content calls, and transport-level mTLS SSL context alignment.

## Body
Google Gen AI SDK version 2.31.0 has been released with the following updates: - Features: Added 'gemini-4-argon' to the Model enum. - Bug Fixes: Fixed parsing of union types in function declarations (resolving issue 3060). Improved automatic continuation handling by clearing continuation state and retaining prompt feedback on empty candidate hops, properly merging grounding metadata across content generation streams, and enabling continuation streams to retry dropped hops while halting on prompt feedback. Updated transport logic to match mTLS endpoints to SSL contexts across transports including plain aiohttp.

## Recommended actions
- Upgrade to Google Gen AI SDK v2.31.0 if using automatic continuation streaming or union types in function calling declarations.
- Reference the new 'gemini-4-argon' enum entry if targeting that specific model.

## Sponsors
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## Agent-readable Sponsor Surface
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