Python: [Bug]: Foundry Toolbox web search citations are missing from hosted agent responses #10325

Observed Behavior

When a Python hosted agent searches the web through a Foundry Toolbox, the search completes but the final answer has no citations. In testing, the Toolbox server returned 4 citations for a FoundryToolbox agent and 17 for a generic MCPStreamableHTTPTool connected to a Toolbox. Both final answers had 0 citations. The citations are already missing from the model's final response, before Teams or another host displays it.

Expected Behavior

Toolbox web search should give the same citation experience as the native web search tool. The model should receive the search result text, and the final answer should include the retrieved sources as citations that the host can display. Forwarding the citation metadata to the model as plain JSON text is not enough.

Steps to Reproduce

1. Create a Python hosted agent with Foundry hosting and a Foundry Toolbox that includes web search. Connect it with either FoundryToolbox or a generic MCPStreamableHTTPTool pointed at the Toolbox endpoint
2. Ask a question that triggers a web search
3. Check the raw Toolbox tool result. It contains search text plus url_citation annotations
4. Check the final response. It has no citations
5. For comparison, run the same question with the native web search tool (client.get_web_search_tool()). That response does include citations

Minimal Reproduction

• In the foundry-samples repository, samples 4 (Foundry Toolbox) and 6 (generic MCP connected to a Toolbox) reproduce the problem
• Samples 19 and 21 (main-agent search) use the native web search tool and return citations as expected

Error Messages and Stack Traces

Package Versions

agent-framework-core: 1.24

Python Version

Python 3.13

Operating System

Windows

Regression

Unknown

Additional Context

No response

Acknowledgements

• I searched existing issues and did not find a duplicate.
• I personally verified this behavior and the reproduction details are authentic.
• I will wait for explicit maintainer agreement before starting implementation of a non-trivial change.