[Release] google/adk-python v1.25.0: v1.25.0

Google ADK Python v1.25.0 release introduces significant enhancements including a simple prompt optimizer demo, new CLI flags for auto session creation, event-delta memory management, and post-invocation token compaction. The release adds support for external access tokens in Google credentials, new tools like MCP resource loading and SkillToolset, plus health/version endpoints to the web server. Multiple bug fixes address async iteration, event loop issues, metadata preservation in streaming responses, and PostgreSQL timestamp handling.

Key Points

• •Add `--auto_create_session` flag to `adk api_server` CLI for automatic session initialization
• •Implement post-invocation token-threshold compaction with event retention to optimize memory usage
• •Add `add_events_to_memory` facade for event-delta operations to streamline event handling
• •Introduce simple prompt optimizer demo for the optimization interface to improve prompt quality
• •Add `/health` and `/version` endpoints to ADK web server for monitoring and version tracking
• •Support externally passed access tokens in Google credentials config for flexible authentication
• •Add SkillToolset and MCP resource loading tools to expand agent capabilities
• •Fix async iteration for VertexAiSessionService pagination and event loop closed bugs in McpSessionManager
• •Preserve thought_signature and grounding/citation metadata in streaming responses for API integration
• •Generate conformance test reports via `adk conformance test` command for quality assurance

Concepts