Support Grounding Metadata / Citation Propagation in in mcp_tool class

[davemorris-gcp]

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Contribution guide.

Is your feature request related to a specific problem?

I don't know how to propagate grounding_metadata / sources from an MCP tool response into the LlmResponse class.

Describe the Solution You'd Like

It seems like the propagate_grounding_metadata feature of agent_tool would be a good way to achieve this in mcp_tool:

adk-python/src/google/adk/tools/agent_tool.py

Line 129 in 7e8965d

propagate_grounding_metadata: bool = False,

Impact on your work

When I register an ADK agent in Gemini Enterprise, that uses mcp_tool, the sources from the MCP server are stripped out when the LlmResponse is built and sent back to the GE UI.

Willingness to contribute

No

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🟡 Recommended Information

Describe Alternatives You've Considered

Something like this: #1693 (comment)

Proposed API / Implementation

It seems like the propagate_grounding_metadata feature of agent_tool would be a good way to achieve this in mcp_tool:

adk-python/src/google/adk/tools/agent_tool.py

Line 129 in 7e8965d

propagate_grounding_metadata: bool = False,

Additional Context

N/A