Google Antigravity Python SDK — v0.1.4 Release Notes

[karmel]

The v0.1.4 release of the Google Antigravity Python SDK introduces major architectural refactorings, public API standardizations, and key new capabilities. The release is 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.

🌟 Key Highlights

• Centralized Multi-Model Configuration: Replaces legacy, singular model configurations with a unified, repeated list of models in configuration classes, enabling future-proof integration of multi-model routing, fallback strategies, and automated selection helpers.
• 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.
• 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, while standardizing top-level package namespace exports.
• Base URL and HTTP Headers Support: Out-of-the-box support for setting custom base URLs and HTTP header.

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📋 Detailed Changes

Model Context Protocol (MCP)

• MCP Server Environment Variables: Added support for configuring and passing custom environment variables to launched stdio servers via the new env field in McpStdioServer (@NTaylorMullen)

Features & Enhancements

• Multi-Model Support: Replaced singular gemini_config options with a repeated models collection on AgentConfig and LocalAgentConfig to support robust backend model configuration (@NTaylorMullen)
• Built-in Web Search Tool: Exposed the built-in SEARCH_WEB tool in the SDK, wired internal serialization structures, and provided a web_tools.py runnable example showing end-to-end web search grounding (@abhipatel12 )
• Image Generation Aspect Ratio: Updated the SDK model config and wrapper to support specifying aspect_ratio within the image creation tool configuration (@abhipatel12)
• 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 (@NTaylorMullen)
• Hook Base Class Exports: Consolidated the base hooks implementation by exporting DecideHook, InspectHook, and TransformHook from the hooks package root (@NTaylorMullen)
• Top-Level Policy Package: Created a new top-level policy package to clean up hook and workspace path validation dependencies (@NTaylorMullen)
• Relocated Trigger Types: Moved the FileChange model and FileChangeKind enum from types.py to the specialized triggers package (@NTaylorMullen)

API Changes

• Removed Dynamic Hook and Trigger Registrations: Eliminated the runtime-mutable register_hook() and register_trigger() methods from Agent, enforcing starting session config safety (@NTaylorMullen)
• Interactive Loop Refactoring: Redesigned run_interactive_loop() to accept a pre-configured AgentConfig instead of requiring an already started agent (@NTaylorMullen)
• ToolContext Scope Realignment: Refactored ToolContext to wrap and derive from Conversation instead of Connection to match its true conversation lifecycle scope (@NTaylorMullen)
• Hook State API Renaming: Renamed HookContext methods get() -> get_state() and set() -> set_state() to prevent name collisions with standard Python object/dictionary lookups (@NTaylorMullen)
• Legacy Configuration Cleanup: Deprecated and removed unused, duplicate, or legacy symbols, arguments, and structures, such as GenerationConfig, ModelEntry, _LegacyModelConfig, GeminiConfig, and the server-side URL context fields (@NTaylorMullen, @abhipatel)
• Connection Interface Consolidation: Removed obsolete lifecycle methods delete() and signal_idle() from connection classes (@NTaylorMullen)
• Absolute Path Harnesses: Patched the local connection strategy to support absolute target paths in ANTIGRAVITY_HARNESS_PATH (@NTaylorMullen)
• Integration Test Expansion: Added concrete assertion criteria for key examples under the getting started modules, ensuring stability in continuous workflows (@karmel)
• Vertex AI Configuration Documentation: Authored ADC authentication steps and configuration guides for Vertex AI integrations in the public README and skill files (@karmel)

Bug Fixes

• Tool Runner Async Checks: Enhanced the _is_async utility to correctly detect asynchronous callables wrapped with ToolWithSchema, preventing async tools from being executed on synchronous threadpools (@NTaylorMullen)
• State Preservation in Copying: Overrode model_copy on AgentConfig to ensure stateful component references (hooks, triggers, tools) are fully preserved when deep-copying configuration states (@NTaylorMullen)
• HTTP 429 Error Propagation: Guaranteed that local execution errors from model exhaustion (HTTP status 429) cleanly propagate up as an AntigravityExecutionError (@NTaylorMullen)
• Multimodal Pipeline Resolution: Corrected the multimodal pipeline example to cleanly resolve MIME types across both .jpg and .jpeg extensions gracefully (@karmel)