`tool_context.actions.skip_summarization = True` makes the agent's response be flagged as coming from user

[germolinal]

Describe the Bug:

I can create a PR, but I am not sure if this is by design or not...

I am trying to return a tool result directly to the user (without summarization). The result is a User message, not an Assistant/model message. (CODE)

Steps to Reproduce:

Create an agent with the following tool using ADK Python 2.6.3:

from google.adk.tools import ToolContext

def check_password(password: str, tool_context: ToolContext):
      tool_context.actions.skip_summarization = True
      return "Your password is correct!"

Expected Behavior:

I would expect the message to be considered a Model/Assistant message (correct me if I am wrong, please)

Observed Behavior:

The message was labeled as coming from the user.

Environment Details:

• ADK Library Version (pip show google-adk): 2.6.3
• Desktop OS:** [e.g., macOS, Linux, Windows]: Windows
• Python Version (python -V): 3.14.3

Model Information:

• Are you using LiteLLM: No
• Which model is being used: e.g., gemini-3.5-flash

How often has this issue occurred?:

• Always (100%)