fix: Handle App objects in eval and graph endpoints

[ejfn]

Description

Fixes #3059

This PR fixes two endpoints in adk web that fail when using App objects instead of bare agents.

Changes

• Eval execution endpoint (line ~969): Extract root_agent from App objects before passing to LocalEvalService
• Graph visualization endpoint (line ~1308): Extract root_agent from App objects before graph operations

Both endpoints now properly handle both BaseAgent and App objects by checking the type and extracting .root_agent when needed.

Testing Plan

Manual E2E Testing with ADK Web

Tested with an App object that includes context caching:

from google.adk.apps import App
from google.adk.agents import LlmAgent

root_agent = LlmAgent(name="MyAgent", model="gemini-1.5-pro-002")
app = App(
    name="my_agent",
    root_agent=root_agent,
    context_cache_config=ContextCacheConfig(...)
)

Before fix:

• Graph visualization failed (tried to call agent methods on App object)
• Eval execution failed (LocalEvalService received App instead of agent)

After fix:

• Graph visualization works correctly
• Eval execution works correctly
• Both endpoints properly extract root_agent from App objects

Checklist

• Code follows project style (autoformat.sh passed)
• Changes are focused and minimal
• Issue adk web: Multiple endpoints fail with App objects #3059 created and referenced
• Manual E2E testing completed

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[gemini-code-assist]

Summary of Changes

Hello @ejfn, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical compatibility issue within the adk web tool, specifically concerning its eval and graph endpoints. Previously, these functionalities would fail when interacting with App objects, expecting BaseAgent instances instead. The changes introduce robust type checking and extraction logic, ensuring that the underlying root_agent is correctly identified and utilized, thereby enabling seamless operation with both BaseAgent and App objects across the affected endpoints.

Highlights

• App Object Compatibility: The pull request resolves an issue where adk web endpoints failed when App objects were used instead of bare agents, ensuring proper handling for both.
• Eval Execution Endpoint Fix: The run_eval endpoint now correctly extracts the root_agent from App objects before passing them to the LocalEvalService.
• Graph Visualization Endpoint Fix: The get_event_graph endpoint has been updated to extract the root_agent from App objects, allowing graph operations to proceed without errors.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request correctly addresses an issue where App objects were not handled correctly in the run_eval and get_event_graph endpoints. The fix involves checking if the loaded object is an App and extracting its root_agent property. While the logic is correct, it introduces code duplication. My feedback suggests refactoring this repeated logic into a private helper method to improve maintainability.

[ejfn]

It seems most of issues originally fixed by this PR has been already fixed by other contributors, the only thing left is the eval api. I will keep this open until that's fixed.

[hangfei]

merged. thanks for your contribution!