Google Antigravity SDK 0.1.5

Changelog: Streaming tool calls, custom subagent delegates, and thread safety enhancements

This release introduces native OpenTelemetry tracing support, declarative subagent configurations, improved type safety, and critical robustness and compatibility updates.

Improvements(5)

• OpenTelemetry tracing support: Integrates OpenTelemetry tracing into the SDK to translate session, turn, step, and tool lifecycle events into standard GenAI-compliant semantic spans for advanced monitoring and performance debugging, with custom task-safe active span propagation for tool execution.
• Declarative subagent configurations: Added SubagentConfig and SubagentCapabilities in types.py to support constructing static subagents with declarative instructions and tools directly.
• Type safety in AgentConfig: Type-annotated policies, hooks, and triggers parameters on AgentConfig and its subclasses to improve type safety and overall developer experience.
• Lifecycle hook routing: Shifted core orchestration of OnSessionStartHook, turn-level hooks (PRE_TURN and POST_TURN), and OnSessionEndHook to the connection layer, implementing the Python-side HookRouter for event routing.
• Public API cleanup: Hid internal validation methods on media and error classes by prefixing them with an underscore (_validate_mime_type and _from_pydantic on validation errors).

Fixes(2)

• Historical step absorption: Ensured historical step absorption is properly drained during initialization to prevent persistence non-linearity issues in Conversation.
• Python 3.14 compatibility: Resolved potential name shadowing in the Conversation class by renaming the top-level connection module import.

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