feat: Add output schema definitions for server responses in simple tools and low-level server tests

Author: PratyushNag

examples/servers/simple-streamablehttp-stateless/mcp_simple_streamablehttp_stateless/server.py

@@ -99,6 +99,14 @@ async def list_tools() -> list[types.Tool]:
                         },
                     },
                 },
+                outputSchema={
+                    "type": "array",
+                    "items": {
+                        "type": "object",
+                        "description": "TextContent with notification information",
+                    },
+                    "description": "List of text content with notification results",
+                },
             )
         ]
 

examples/servers/simple-tool/mcp_simple_tool/server.py

@@ -54,6 +54,17 @@ async def list_tools() -> list[types.Tool]:
                         }
                     },
                 },
+                outputSchema={
+                    "type": "array",
+                    "items": {
+                        "anyOf": [
+                            {"type": "object", "description": "TextContent"},
+                            {"type": "object", "description": "ImageContent"},
+                            {"type": "object", "description": "EmbeddedResource"},
+                        ]
+                    },
+                    "description": "List of content from the fetched website",
+                },
             )
         ]
 

tests/server/test_lowlevel_tool_annotations.py

@@ -38,6 +38,7 @@ async def list_tools():
                     },
                     "required": ["message"],
                 },
+                outputSchema={"type": "string", "description": "The echoed message"},
                 annotations=ToolAnnotations(
                     title="Echo Tool",
                     readOnlyHint=True,
@@ -54,9 +55,11 @@ async def list_tools():
 
     # Message handler for client
     async def message_handler(
-        message: RequestResponder[ServerRequest, ClientResult]
-        | ServerNotification
-        | Exception,
+        message: (
+            RequestResponder[ServerRequest, ClientResult]
+            | ServerNotification
+            | Exception
+        ),
     ) -> None:
         if isinstance(message, Exception):
             raise message