ValueError: {agent} not found in agent tree.

[adt5-uiuc]

Describe the solution you'd like
I'm trying to make my agents create other agents. I'm working around the workflow to that purpose, but sometimes they try to address other agents before they're created and I get a ValueError exception, because the agent is not in the tree yet.

Since this is code that is run deep within ADK, how I can catch those exceptions and handle them?

Additional context
OS: Mac OS 15.4.1
Python version(python -V): 1.13.2
ADK version(pip show google-adk): 1.6.1

[jpantsjoha]

I've submitted a PR that enhances the "Agent not found in the agent tree" error message:

PR #3219: #3219

The enhanced error messages now provide:

• List of available agents in the agent tree (for easy debugging)
• Possible causes (timing issues, typos, registration problems)
• Suggested fixes with actionable steps
• Fuzzy matching to catch typos

This addresses the issue of cryptic error messages when agents are referenced before creation or with typos, making it much easier to diagnose and fix agent tree issues.

While the error still occurs deep within ADK, the enhanced message provides enough context to quickly identify and resolve the problem.