Two Nasty Gotchas When Building Multi-Agent Systems with Google ADK

Google's Agent Development Kit (ADK) makes it straightforward to compose LlmAgent instances into multi-agent hierarchies. But two bugs bit me hard in production that aren't documented anywhere. Here's what happened and how to fix them. The Setup A root router LlmAgent with two sub-agents. Both sub-agents are module-level singletons — instantiated at import time, referenced from the root agent's constructor. # Agents/my_app/root_agent.py from Agents.my_app.sub_agent_a.agent import sub_agent_a fro