fix: fix serialize case by case since EmbededResource has uri which is not JSON serialized

Author: perfogic

python/packages/autogen-ext/src/autogen_ext/tools/mcp/_base.py

@@ -7,8 +7,9 @@
 from autogen_core.tools import BaseTool
 from autogen_core.utils import schema_to_pydantic_model
 from mcp import ClientSession, Tool
-from mcp.types import EmbeddedResource, ImageContent, TextContent
+from mcp.types import AnyUrl, EmbeddedResource, ImageContent, TextContent
 from pydantic import BaseModel
+import json
 
 from ._config import McpServerParams
 from ._session import create_mcp_server_session
@@ -116,16 +117,23 @@ async def from_server_params(cls, server_params: TServerParams, tool_name: str)
 
         return cls(server_params=server_params, tool=matching_tool)
 
-    def return_value_as_string(self, value: Any) -> str:
-        if isinstance(value, list):
-            valid_types = (TextContent, ImageContent, EmbeddedResource)
-            return list(
-                map(
-                    lambda t: (t.model_dump_json() if isinstance(t, valid_types) else str(t)),
-                    value,
-                )
-            )
-        return str(value)
+    def return_value_as_string(self, value: list) -> str:
+        """Return a string representation of the result."""
+
+        def serialize_item(item):
+            if isinstance(item, (TextContent, ImageContent)):
+                return item.model_dump()
+            elif isinstance(item, EmbeddedResource):
+                type = item.type
+                resource = {}
+                for key, val in item.resource.model_dump().items():
+                    if isinstance(val, AnyUrl):
+                        resource[key] = str(val)
+                annotations = item.annotations.model_dump() if item.annotations else None
+                return {"type": type, "resource": resource, "annotations": annotations}
+            else:
+                return str(item)
+        return json.dumps([serialize_item(item) for item in value])
 
     def _format_errors(self, error: Exception) -> str:
         """Recursively format errors into a string."""

python/packages/autogen-ext/tests/tools/test_mcp_tools.py

@@ -16,7 +16,14 @@
     mcp_server_tools,
 )
 from mcp import ClientSession, Tool
-from mcp.types import EmbeddedResource, ImageContent, TextContent, TextResourceContents
+from mcp.types import (
+    AnyUrl,
+    Annotations,
+    EmbeddedResource,
+    ImageContent,
+    TextContent,
+    TextResourceContents,
+)
 
 
 @pytest.fixture
@@ -202,29 +209,29 @@ async def test_adapter_from_server_params_with_return_value_as_string(
 
     adapter = await StdioMcpToolAdapter.from_server_params(sample_server_params, "test_tool")
 
-    assert (
-        adapter.return_value_as_string(
+    assert adapter.return_value_as_string(
             [
-                TextContent(text="this is a sample text", type="text"),
+                TextContent(
+                    text="this is a sample text",
+                    type="text",
+                    annotations=Annotations(audience=["user", "assistant"], priority=0.7),
+                ),
                 ImageContent(
                     data="this is a sample base64 encoded image",
                     mimeType="image/png",
                     type="image",
+                    annotations=None,
                 ),
                 EmbeddedResource(
                     type="resource",
                     resource=TextResourceContents(
                         text="this is a sample text",
-                        uri="http://example.com/test",
+                        uri=AnyUrl(url="http://example.com/test"),
                     ),
+                    annotations=Annotations(audience=["user"], priority=0.3),
                 ),
             ]
-        )
-    ) == [
-        '{"type":"text","text":"this is a sample text","annotations":null}',
-        '{"type":"image","data":"this is a sample base64 encoded image","mimeType":"image/png","annotations":null}',
-        '{"type":"resource","resource":{"uri":"http://example.com/test","mimeType":null,"text":"this is a sample text"},"annotations":null}',
-    ]
+    ) == '[{"type": "text", "text": "this is a sample text", "annotations": {"audience": ["user", "assistant"], "priority": 0.7}}, {"type": "image", "data": "this is a sample base64 encoded image", "mimeType": "image/png", "annotations": null}, {"type": "resource", "resource": {"uri": "http://example.com/test"}, "annotations": {"audience": ["user"], "priority": 0.3}}]'
 
 
 @pytest.mark.asyncio