Adk Framework

Skill: ADK Framework

This skill covers expert architectural patterns, routing strategies, and troubleshooting guidelines for the Google Agent Development Kit (ADK).

1. Multi-Agent Structure

• Discovery Rule: Only the root_agent defined in agent.py or root_agent.yaml is automatically surfaced in the platform web UI. Sub-agents are invisible to the top-level application but are called natively via routing.
• Routing Rules: Always provide the list of sub-agents directly to the parent agent via the sub_agents attribute. Do not construct wrapper functions to trigger a sub-agent manually.

2. Architectural Patterns

• Relay/Router Pattern:
  • Design the orchestrator agent to act exclusively as a request classifier.
  • Direct it to output strict XML-like signals (e.g., <route>ROUTING_TO_RAG</route>).
  • Catch this signal in the main execution loop, running only the appropriate target agent to prevent nested agent call stacks and context pollution.
• Capabilities Discovery Pattern:
  • When a user queries broad knowledge (e.g., "what do you know?"), trigger searches for broad index terms like "Overview" or provide a predefined hardcoded list of capabilities.

3. Routing Strategies

• File Presence Pattern: Route to file-processing agents only if the user attaches a file or references "this attachment". Route to RAG/Knowledge agents for general queries and report generation.
• Strict Evaluation Order: Categorize intents explicitly (e.g., [1] DIRECT, [2] RAG, [3] CHAT) and designate one specific category as the default fallback. Avoid negative constraint prompts.

4. Prompt Engineering Best Practices

• No Preamble Rule: When an agent triggers a tool, harden the prompt to prohibit introductory filler (e.g., forbid saying "I can help with that"). Insist that the agent's first and only action must be to call the tool.