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

📰 Dev.to · Hiroshi Toyama

Learn to avoid two common pitfalls when building multi-agent systems with Google ADK, ensuring smoother production deployments.

intermediate Published 28 Apr 2026

Action Steps

Identify potential singleton issues in module-level sub-agents
Implement proper synchronization mechanisms for concurrent access
Review Google ADK documentation for updates on multi-agent systems
Test multi-agent hierarchies thoroughly before production deployment
Apply fixes for known issues with LlmAgent instances

Who Needs to Know This

Developers and engineers working with Google ADK and multi-agent systems can benefit from this knowledge to prevent production errors.

Key Insight

💡 Properly handling singleton sub-agents and synchronization is crucial for stable multi-agent systems with Google ADK.

Key Takeaways

Learn to avoid two common pitfalls when building multi-agent systems with Google ADK, ensuring smoother production deployments.

Full Article

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

URL Source: https://dev.to/toyama0919/two-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05

Published Time: 2026-04-28T09:30:43Z

Markdown Content:
# Two Nasty Gotchas When Building Multi-Agent Systems with Google ADK - DEV Community
[Skip to content](https://dev.to/toyama0919/two-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05#main-content)

[![Image 1: DEV Community](https://media2.dev.to/dynamic/image/quality=100/https://dev-to-uploads.s3.amazonaws.com/uploads/logos/resized_logo_UQww2soKuUsjaOGNB38o.png)](https://dev.to/)

[Powered by Algolia](https://www.algolia.com/developers/?utm_source=devto&utm_medium=referral)

[Log in](https://dev.to/enter?signup_subforem=1)[Create account](https://dev.to/enter?signup_subforem=1&state=new-user)

## DEV Community

![Image 2](https://assets.dev.to/assets/heart-plus-active-9ea3b22f2bc311281db911d416166c5f430636e76b15cd5df6b3b841d830eefa.svg)0 Add reaction

![Image 3](https://assets.dev.to/assets/sparkle-heart-5f9bee3767e18deb1bb725290cb151c25234768a0e9a2bd39370c382d02920cf.svg)0 Like ![Image 4](https://assets.dev.to/assets/multi-unicorn-b44d6f8c23cdd00964192bedc38af3e82463978aa611b4365bd33a0f1f4f3e97.svg)0 Unicorn ![Image 5](https://assets.dev.to/assets/exploding-head-daceb38d627e6ae9b730f36a1e390fca556a4289d5a41abb2c35068ad3e2c4b5.svg)0 Exploding Head ![Image 6](https://assets.dev.to/assets/raised-hands-74b2099fd66a39f2d7eed9305ee0f4553df0eb7b4f11b01b6b1b499973048fe5.svg)0 Raised Hands ![Image 7](https://assets.dev.to/assets/fire-f60e7a582391810302117f987b22a8ef04a2fe0df7e3258a5f49332df1cec71e.svg)0 Fire

0 Jump to Comments 0 Save Boost

Copy link

Copied to Clipboard

[Share to X](https://twitter.com/intent/tweet?text=%22Two%20Nasty%20Gotchas%20When%20Building%20Multi-Agent%20Systems%20with%20Google%20ADK%22%20by%20%40toyama0919%20%23DEVCommunity%20https%3A%2F%2Fdev.to%2Ftoyama0919%2Ftwo-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05)[Share to LinkedIn](https://www.linkedin.com/shareArticle?mini=true&url=https%3A%2F%2Fdev.to%2Ftoyama0919%2Ftwo-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05&title=Two%20Nasty%20Gotchas%20When%20Building%20Multi-Agent%20Systems%20with%20Google%20ADK&summary=Google%27s%20Agent%20Development%20Kit%20%28ADK%29%20makes%20it%20straightforward%20to%20compose%20LlmAgent%20instances%20into...&source=DEV%20Community)[Share to Facebook](https://www.facebook.com/sharer.php?u=https%3A%2F%2Fdev.to%2Ftoyama0919%2Ftwo-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05)[Share to Mastodon](https://s2f.kytta.dev/?text=https%3A%2F%2Fdev.to%2Ftoyama0919%2Ftwo-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05)

[Share Post via...](https://dev.to/toyama0919/two-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05#)[Report Abuse](https://dev.to/report-abuse)

[![Image 8: Hiroshi Toyama](https://media2.dev.to/dynamic/image/width=50,height=50,fit=cover,gravity=auto,format=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F41804%2F7c54b968-6837-4276-9b8a-ac8f060c6f18.png)](https://dev.to/toyama0919)

[Hiroshi Toyama](https://dev.to/toyama0919)
Posted on Apr 28

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

[#googleadk](https://dev.to/t/googleadk)[#llm](https://dev.to/t/llm)[#python](https://dev.to/t/python)[#multiagent](https://dev.to/t/multiagent)

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.

## [](https://dev.to/toyama0919/two-nasty-gotchas-when-building-multi-agent-systems-with-google-adk-3d05#the-setup) The Setup

A root router `LlmAgent` with two sub-agents. Both sub-agents are module-level singletons — instanti

Read full article → ← Back to Reads

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

Key Takeaways

Full Article

Related Videos