Agent Skills: adk-agent-handling

Google ADK (Agent Development Kit) multi-agent system architecture for BigQuery data analytics. Covers BigQuery agent vs conversational agent patterns, ADK Single Parent Rule, domain routing with sub-agents, agent selection mechanisms, SQL error recovery with ReflectAndRetryToolPlugin, transfer_to_agent workflows, and frontend-backend agent coordination. Use when working with Google ADK agents, multi-agent systems, BigQuery SQL automation, domain expert routing, agent orchestration, or implementing error recovery strategies in AI agent applications.