An enterprise is building a multi-agent system on Vertex AI Agent Builder. A primary orchestrator agent must delegate tasks to specialized sub-agents: one for HR policy lookups and one for IT ticket creation. The team wants the orchestrator to call sub-agents programmatically and pass context between them. Which Agent Builder capability enables this inter-agent delegation pattern?
- A. Use Vertex AI Pipelines to orchestrate agent calls as pipeline components, passing outputs between steps via artifact parameters
- B. Configure the orchestrator agent with multiple Data Stores, one per domain, and use routing rules to select the correct store per query
- C. Use the Agent Builder Agent-as-a-Tool feature, registering each sub-agent as a callable tool available to the orchestrator agent✓ Correct
- D. Deploy each sub-agent as a separate Cloud Run service and configure Pub/Sub to pass messages between them outside of Agent Builder
Explanation
Vertex AI Agent Builder supports an 'Agent as a Tool' pattern where a sub-agent is registered as a tool that can be invoked by an orchestrator (parent) agent. The orchestrator's reasoning loop can call the sub-agent tool with structured input and receive its output, enabling context passing and delegation across specialized agents — all within the Agent Builder framework. Using multiple Data Stores with routing rules handles knowledge retrieval, not agent-to-agent delegation with context passing. Deploying sub-agents as Cloud Run services with Pub/Sub is a custom engineering approach that bypasses Agent Builder's managed orchestration and is significantly more complex to maintain. Vertex AI Pipelines is designed for ML workflow orchestration (training, evaluation), not for wiring together live conversational agents at inference time.