[UserWarning] Pydantic warning when using SequentialAgent due to attribute shadowing

[pierregrothe]

I've noticed a PydanticUserWarning is triggered when using the SequentialAgent class. It seems to be caused by attribute shadowing between the child SequentialAgent and its parent BaseAgent.

Environment:

Python Version: 3.13.6

Pydantic Version: 2.11.7

google-adk Version: 1.10.0

Problem Description:
When importing or instantiating the SequentialAgent, the following warning is displayed:

.../pydantic/_internal/_fields.py:198: UserWarning: Field name "config_type" in "SequentialAgent" shadows an attribute in parent "BaseAgent"
warnings.warn(

Expected Behavior:
The code should execute without raising any UserWarning from Pydantic, assuming the shadowing is intended and handled.

Actual Behavior:
The UserWarning is consistently logged to the console, creating unnecessary noise and potential confusion about which config_type attribute is being used.

[adk-bot]

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: This is a known issue. You can suppress the PydanticUserWarning by adding a filter for UserWarning from pydantic.

---

Hello @pierregrothe,

Thank you for reporting this.

The PydanticUserWarning you're seeing is due to the config_type attribute being intentionally overridden in the SequentialAgent class [1]. While this is a known side effect of the current design, we understand that the warning can be noisy.

As a workaround, you can suppress this specific warning by adding the following code to your application's entry point:

import warnings

warnings.filterwarnings("ignore", category=UserWarning, module="pydantic")

This will prevent the warning from being displayed without affecting the functionality of the SequentialAgent. This is the approach used in some of our example applications [2, 3].

We will continue to monitor this and consider a more permanent solution in a future release.

---

[1] https://github.com/google/adk-python/blob/main/src/google/adk/agents/sequential_agent.py
[2] https://github.com/google/adk-docs/blob/main/examples/python/snippets/streaming/adk-streaming-ws/app/main.py
[3] https://github.com/google/adk-docs/blob/main/examples/python/snippets/streaming/adk-streaming/app/main.py