Google Antigravity SDK 0.1.4

Changelog: Async tool execution buffers, memory state persistence, and error handling improvements

This release introduces major architectural refactorings, public API standardizations, and key new capabilities centered on centralizing model configurations to natively support multi-model backends, exposing a new built-in Google Web Search capability, enabling environment variable passing for Model Context Protocol (MCP) servers, and simplifying the agent initialization flow by removing dynamic runtime registrations.

Improvements(10)

• Built-in web search tool: Exposes the SEARCH_WEB tool directly within the SDK, enabling agents to leverage Google Search for grounded real-time information retrieval, complete with new developer examples (web_tools.py).
• MCP server environment variables: Added support for configuring and passing custom environment variables to launched stdio servers using the new env field in McpStdioServer.
• Base URL and HTTP headers support: Out-of-the-box support for setting custom base URLs and HTTP headers.
• Image generation aspect ratio: Updated the SDK model config and wrapper to support specifying aspect_ratio within the image creation tool configuration.
• Centralized multi-model configuration: Replaces legacy singular gemini_config options with a unified, repeated models collection on AgentConfig and LocalAgentConfig to support multi-model routing, fallback strategies, and automated selection helpers.
• Agent session lifecycle and API standardization: Improves runtime safety by removing dynamic post-initialization hook and trigger registration in favor of session creation-time declarations.
• Top-level package exports: Exposed core SDK constructs (including Content, Image, Document, Audio, Video, from_file, BuiltinTools, and SystemInstructions) directly under the google.antigravity root module for easier access.
• Hook base class exports: Consolidated the base hooks implementation by exporting DecideHook, InspectHook, and TransformHook from the hooks package root.
• Top-level policy package: Created a new top-level policy package to clean up hook and workspace path validation dependencies.
• Relocated trigger types: Moved the FileChange model and FileChangeKind enum from types.py to the specialized triggers package.

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