Python: Add include_reference_source_data to agentic search requests

Pass knowledge_source_params with include_reference_source_data=True to
both KnowledgeBaseRetrievalRequest constructions in _agentic_search().
Without this parameter, ref.source_data is always None even when the
knowledge source has source_data_fields configured.

Fixes #5095

Author: mvanhorn

python/packages/azure-ai-search/agent_framework_azure_ai_search/_context_provider.py

@@ -64,6 +64,7 @@
         KnowledgeBaseRetrievalResponse,
         KnowledgeRetrievalIntent,
         KnowledgeRetrievalSemanticIntent,
+        KnowledgeSourceParams,
     )
     from azure.search.documents.knowledgebases.models import (
         KnowledgeRetrievalLowReasoningEffort as KBRetrievalLowReasoningEffort,
@@ -99,6 +100,7 @@
         KnowledgeBaseRetrievalResponse,
         KnowledgeRetrievalIntent,
         KnowledgeRetrievalSemanticIntent,
+        KnowledgeSourceParams,
     )
     from azure.search.documents.knowledgebases.models import (
         KnowledgeRetrievalLowReasoningEffort as KBRetrievalLowReasoningEffort,
@@ -830,6 +832,12 @@ async def _agentic_search(self, messages: list[Message]) -> list[Message]:
                 retrieval_reasoning_effort=reasoning_effort,
                 output_mode=output_mode,
                 include_activity=True,
+                knowledge_source_params=[
+                    KnowledgeSourceParams(
+                        knowledge_source_name=f"{self.index_name}-source",
+                        include_reference_source_data=True,
+                    ),
+                ],
             )
         else:
             kb_messages = self._prepare_messages_for_kb_search(messages)
@@ -838,6 +846,12 @@ async def _agentic_search(self, messages: list[Message]) -> list[Message]:
                 retrieval_reasoning_effort=reasoning_effort,
                 output_mode=output_mode,
                 include_activity=True,
+                knowledge_source_params=[
+                    KnowledgeSourceParams(
+                        knowledge_source_name=f"{self.index_name}-source",
+                        include_reference_source_data=True,
+                    ),
+                ],
             )
 
         if not self._retrieval_client:

python/packages/azure-ai-search/tests/test_aisearch_context_provider.py

@@ -1310,6 +1310,72 @@ async def test_none_response_returns_default_message(self) -> None:
         assert len(results) == 1
         assert results[0].text == "No results found from Knowledge Base."
 
+    async def test_minimal_reasoning_includes_knowledge_source_params(self) -> None:
+        provider = _make_provider()
+        provider._knowledge_base_initialized = True
+        provider.knowledge_base_name = "kb"
+        provider.retrieval_reasoning_effort = "minimal"
+
+        mock_content = Mock()
+        mock_content.text = "Answer"
+        mock_message = Mock()
+        mock_message.role = "assistant"
+        mock_message.content = [mock_content]
+        mock_result = Mock()
+        mock_result.response = [mock_message]
+        mock_result.references = None
+
+        mock_retrieval = AsyncMock()
+        mock_retrieval.retrieve = AsyncMock(return_value=mock_result)
+        provider._retrieval_client = mock_retrieval
+
+        with patch(
+            "agent_framework_azure_ai_search._context_provider.KnowledgeBaseMessageTextContent",
+            type(mock_content),
+        ):
+            await provider._agentic_search([Message(role="user", contents=["query"])])
+
+        call_kwargs = mock_retrieval.retrieve.call_args
+        request = call_kwargs.kwargs.get("retrieval_request") or call_kwargs.args[0]
+        assert request.knowledge_source_params is not None
+        assert len(request.knowledge_source_params) == 1
+        params = request.knowledge_source_params[0]
+        assert params.knowledge_source_name == "test-index-source"
+        assert params.include_reference_source_data is True
+
+    async def test_non_minimal_reasoning_includes_knowledge_source_params(self) -> None:
+        provider = _make_provider()
+        provider._knowledge_base_initialized = True
+        provider.knowledge_base_name = "kb"
+        provider.retrieval_reasoning_effort = "medium"
+
+        mock_content = Mock()
+        mock_content.text = "Answer"
+        mock_message = Mock()
+        mock_message.role = "assistant"
+        mock_message.content = [mock_content]
+        mock_result = Mock()
+        mock_result.response = [mock_message]
+        mock_result.references = None
+
+        mock_retrieval = AsyncMock()
+        mock_retrieval.retrieve = AsyncMock(return_value=mock_result)
+        provider._retrieval_client = mock_retrieval
+
+        with patch(
+            "agent_framework_azure_ai_search._context_provider.KnowledgeBaseMessageTextContent",
+            type(mock_content),
+        ):
+            await provider._agentic_search([Message(role="user", contents=["query"])])
+
+        call_kwargs = mock_retrieval.retrieve.call_args
+        request = call_kwargs.kwargs.get("retrieval_request") or call_kwargs.args[0]
+        assert request.knowledge_source_params is not None
+        assert len(request.knowledge_source_params) == 1
+        params = request.knowledge_source_params[0]
+        assert params.knowledge_source_name == "test-index-source"
+        assert params.include_reference_source_data is True
+
 
 # -- before_run: agentic mode --------------------------------------------------