Python: Correction of MCP image type conversion in _mcp.py

python/packages/core/agent_framework/_mcp.py

@@ -152,7 +152,7 @@ def _mcp_type_to_ai_content(
             case types.ImageContent() | types.AudioContent():
                 return_types.append(
                     DataContent(
-                        uri=mcp_type.data,
+                        data=mcp_type.data,
                         media_type=mcp_type.mimeType,
                         raw_representation=mcp_type,
                     )

python/packages/core/agent_framework/_types.py

@@ -925,6 +925,10 @@ class DataContent(BaseContent):
             image_data = b"raw image bytes"
             data_content = DataContent(data=image_data, media_type="image/png")
 
+            # Create from base64-encoded string
+            base64_string = "iVBORw0KGgoAAAANS..."
+            data_content = DataContent(data=base64_string, media_type="image/png")
+
             # Create from data URI
             data_uri = "data:image/png;base64,iVBORw0KGgoAAAANS..."
             data_content = DataContent(uri=data_uri)
@@ -986,11 +990,38 @@ def __init__(
             **kwargs: Any additional keyword arguments.
         """
 
+    @overload
+    def __init__(
+        self,
+        *,
+        data: str,
+        media_type: str,
+        annotations: Sequence[Annotations | MutableMapping[str, Any]] | None = None,
+        additional_properties: dict[str, Any] | None = None,
+        raw_representation: Any | None = None,
+        **kwargs: Any,
+    ) -> None:
+        """Initializes a DataContent instance with base64-encoded string data.
+
+        Important:
+            This is for binary data that is represented as a data URI, not for online resources.
+            Use ``UriContent`` for online resources.
+
+        Keyword Args:
+            data: The base64-encoded string data represented by this instance.
+                The data is used directly to construct a data URI.
+            media_type: The media type of the data.
+            annotations: Optional annotations associated with the content.
+            additional_properties: Optional additional properties associated with the content.
+            raw_representation: Optional raw representation of the content.
+            **kwargs: Any additional keyword arguments.
+        """
+
     def __init__(
         self,
         *,
         uri: str | None = None,
-        data: bytes | None = None,
+        data: bytes | str | None = None,
         media_type: str | None = None,
         annotations: Sequence[Annotations | MutableMapping[str, Any]] | None = None,
         additional_properties: dict[str, Any] | None = None,
@@ -1006,8 +1037,9 @@ def __init__(
         Keyword Args:
             uri: The URI of the data represented by this instance.
                 Should be in the form: "data:{media_type};base64,{base64_data}".
-            data: The binary data represented by this instance.
-                The data is transformed into a base64-encoded data URI.
+            data: The binary data or base64-encoded string represented by this instance.
+                If bytes, the data is transformed into a base64-encoded data URI.
+                If str, it is assumed to be already base64-encoded and used directly.
             media_type: The media type of the data.
             annotations: Optional annotations associated with the content.
             additional_properties: Optional additional properties associated with the content.
@@ -1017,7 +1049,9 @@ def __init__(
         if uri is None:
             if data is None or media_type is None:
                 raise ValueError("Either 'data' and 'media_type' or 'uri' must be provided.")
-            uri = f"data:{media_type};base64,{base64.b64encode(data).decode('utf-8')}"
+
+            base64_data: str = base64.b64encode(data).decode("utf-8") if isinstance(data, bytes) else data
+            uri = f"data:{media_type};base64,{base64_data}"
 
         # Validate URI format and extract media type if not provided
         validated_uri = self._validate_uri(uri)

python/packages/core/tests/core/test_mcp.py

@@ -75,17 +75,21 @@ def test_mcp_call_tool_result_to_ai_contents():
     mcp_result = types.CallToolResult(
         content=[
             types.TextContent(type="text", text="Result text"),
-            types.ImageContent(type="image", data="data:image/png;base64,xyz", mimeType="image/png"),
+            types.ImageContent(type="image", data="xyz", mimeType="image/png"),
+            types.ImageContent(type="image", data=b"abc", mimeType="image/webp"),
         ]
     )
     ai_contents = _mcp_call_tool_result_to_ai_contents(mcp_result)
 
-    assert len(ai_contents) == 2
+    assert len(ai_contents) == 3
     assert isinstance(ai_contents[0], TextContent)
     assert ai_contents[0].text == "Result text"
     assert isinstance(ai_contents[1], DataContent)
     assert ai_contents[1].uri == "data:image/png;base64,xyz"
     assert ai_contents[1].media_type == "image/png"
+    assert isinstance(ai_contents[2], DataContent)
+    assert ai_contents[2].uri == "data:image/webp;base64,abc"
+    assert ai_contents[2].media_type == "image/webp"
 
 
 def test_mcp_call_tool_result_with_meta_error():
@@ -183,7 +187,7 @@ def test_mcp_call_tool_result_regression_successful_workflow():
     mcp_result = types.CallToolResult(
         content=[
             types.TextContent(type="text", text="Success message"),
-            types.ImageContent(type="image", data="data:image/jpeg;base64,abc123", mimeType="image/jpeg"),
+            types.ImageContent(type="image", data="abc123", mimeType="image/jpeg"),
         ]
     )
 
@@ -218,7 +222,8 @@ def test_mcp_content_types_to_ai_content_text():
 
 def test_mcp_content_types_to_ai_content_image():
     """Test conversion of MCP image content to AI content."""
-    mcp_content = types.ImageContent(type="image", data="data:image/jpeg;base64,abc", mimeType="image/jpeg")
+    mcp_content = types.ImageContent(type="image", data="abc", mimeType="image/jpeg")
+    mcp_content = types.ImageContent(type="image", data=b"abc", mimeType="image/jpeg")
     ai_content = _mcp_type_to_ai_content(mcp_content)[0]
 
     assert isinstance(ai_content, DataContent)
@@ -229,7 +234,7 @@ def test_mcp_content_types_to_ai_content_image():
 
 def test_mcp_content_types_to_ai_content_audio():
     """Test conversion of MCP audio content to AI content."""
-    mcp_content = types.AudioContent(type="audio", data="data:audio/wav;base64,def", mimeType="audio/wav")
+    mcp_content = types.AudioContent(type="audio", data="def", mimeType="audio/wav")
     ai_content = _mcp_type_to_ai_content(mcp_content)[0]
 
     assert isinstance(ai_content, DataContent)