0.1.16 August 31, 2026 Default Gemini 3.8 Flash model upgrade, lightweight agent configuration, and Vertex AI Express mode The 0.1.16 release updates the default model for new agents to gemini-3.8-flash for enhanced reasoning capabilities, introduces a .lightweight() method on agent configs for small and local models, adds Vertex AI Express mode with API keys, and expands tool runner support for callable classes and dataclass functors. Improvements (8) Default Model Update to Gemini 3.8 Flash : The default model for new agents and configurations has been updated to gemini-3.8-flash , delivering higher reasoning quality and stronger task performance. Developers can override this default by specifying model in their configuration: Optimized Lightweight Agent Configuration : New .lightweight() method on agent configurations (including LocalAgentConfig and LiteRTAgentConfig ) applies preset optimizations for smaller, local-running models by configuring minimal tool sets, minimal prompting, and disabling background subagents: Vertex AI Express Mode (API Key Support) : Developers can now connect to Vertex AI using Express mode by providing an API key directly on