🔴 Required Information
Please ensure all items in this section are completed to allow for efficient
triaging. Requests without complete information may be rejected / deprioritized.
If an item is not applicable to you - please mark it as N/A
Describe the Bug:
In ADK version 2.0.0, the internal Builder Assistant fails to initialize properly because its default name starts with double underscores (e.g., builder_assistant). This violates the updated Pydantic validation rules introduced in 2.0.0, which strictly enforce that an agent's name attribute must be a valid identifier starting with a letter [a-zA-Z]. Because the framework rejects its own internal component's name, it causes a crash or failure when trying to use the builder features.
Steps to Reproduce:
- Install google-adk version 2.0.0.
- Run adk web in your project folder to launch the Visual Builder (or trigger the workflow that initializes the Builder Assistant).
- Open http://localhost:8000 in your browser.
- Observe the validation error (ValidationError / ValueError) thrown by the framework due to the double underscore naming constraint.
Expected Behavior:
The Builder Assistant should initialize successfully. Internal helper agents should either be exempt from strict user-facing identifier validation rules, or they should be renamed to comply with the "must start with a letter" rule (e.g., renaming builder_assistant to BuilderAssistant).
Observed Behavior:
The application throws a ValidationError or ValueError indicating that the agent name is invalid because it does not start with a letter, blocking the initialization of the Visual Builder.
Environment Details:
- ADK Library Version (pip show google-adk): 2.0.0
- Desktop OS: [e.g., macOS, Linux, Windows]
- Python Version (python -V): Python 3.11+
Model Information:
- Are you using LiteLLM: No
- Which model is being used: gemini-2.0-flash
🟡 Optional Information
Providing this information greatly speeds up the resolution process.
Regression:
Did this work in a previous version of ADK? If so, which one?
Yes, this did not trigger a validation crash in pre-2.0.0 alpha versions before the aggressive Pydantic identifier validation was introduced.
Logs:
Please attach relevant logs. Wrap them in code blocks (```) or attach a text file.
ValidationError: 1 validation error for Agent
name
string does not match regex "^[a-zA-Z][a-zA-Z0-9_-]$" (type=value_error.str.regex; pattern=^[a-zA-Z][a-zA-Z0-9_-]$)
Screenshots / Video:
NA
Additional Context:
Until a patch is released, users can temporarily bypass this issue by manually editing the source code in their local environment (site-packages/google/adk/visual_builder/builder_agent.py) to rename the assistant to a compliant identifier (e.g., BuilderAssistant).
Minimal Reproduction Code:
Please provide a code snippet or a link to a Gist/repo that isolates the issue.
import google.adk.agents.base_agent as base
The error occurs internally when executing:
adk web
How often has this issue occurred?:
Always (100%)
🔴 Required Information
Please ensure all items in this section are completed to allow for efficient
triaging. Requests without complete information may be rejected / deprioritized.
If an item is not applicable to you - please mark it as N/A
Describe the Bug:
In ADK version 2.0.0, the internal Builder Assistant fails to initialize properly because its default name starts with double underscores (e.g., builder_assistant). This violates the updated Pydantic validation rules introduced in 2.0.0, which strictly enforce that an agent's name attribute must be a valid identifier starting with a letter [a-zA-Z]. Because the framework rejects its own internal component's name, it causes a crash or failure when trying to use the builder features.
Steps to Reproduce:
Expected Behavior:
The Builder Assistant should initialize successfully. Internal helper agents should either be exempt from strict user-facing identifier validation rules, or they should be renamed to comply with the "must start with a letter" rule (e.g., renaming builder_assistant to BuilderAssistant).
Observed Behavior:
The application throws a ValidationError or ValueError indicating that the agent name is invalid because it does not start with a letter, blocking the initialization of the Visual Builder.
Environment Details:
Model Information:
🟡 Optional Information
Providing this information greatly speeds up the resolution process.
Regression:
Did this work in a previous version of ADK? If so, which one?
Yes, this did not trigger a validation crash in pre-2.0.0 alpha versions before the aggressive Pydantic identifier validation was introduced.
Logs:
Please attach relevant logs. Wrap them in code blocks (```) or attach a text file.
ValidationError: 1 validation error for Agent
name
string does not match regex "^[a-zA-Z][a-zA-Z0-9_-]$" (type=value_error.str.regex; pattern=^[a-zA-Z][a-zA-Z0-9_-]$)
Screenshots / Video:
NA
Additional Context:
Until a patch is released, users can temporarily bypass this issue by manually editing the source code in their local environment (site-packages/google/adk/visual_builder/builder_agent.py) to rename the assistant to a compliant identifier (e.g., BuilderAssistant).
Minimal Reproduction Code:
Please provide a code snippet or a link to a Gist/repo that isolates the issue.
import google.adk.agents.base_agent as base
The error occurs internally when executing:
adk web
How often has this issue occurred?:
Always (100%)