test: add output schema test

Author: dbschmigelski

tests/strands/tools/mcp/test_mcp_agent_tool.py

@@ -48,6 +48,7 @@ def test_tool_spec_with_description(mcp_agent_tool, mock_mcp_tool):
     assert tool_spec["name"] == "test_tool"
     assert tool_spec["description"] == "A test tool"
     assert tool_spec["inputSchema"]["json"] == {"type": "object", "properties": {}}
+    assert "outputSchema" not in tool_spec
 
 
 def test_tool_spec_without_description(mock_mcp_tool, mock_mcp_client):
@@ -69,6 +70,15 @@ def test_tool_spec_with_output_schema(mock_mcp_tool, mock_mcp_client):
     assert tool_spec["outputSchema"]["json"] == {"type": "object", "properties": {"result": {"type": "string"}}}
 
 
+def test_tool_spec_without_output_schema(mock_mcp_tool, mock_mcp_client):
+    mock_mcp_tool.outputSchema = None
+
+    agent_tool = MCPAgentTool(mock_mcp_tool, mock_mcp_client)
+    tool_spec = agent_tool.tool_spec
+
+    assert "outputSchema" not in tool_spec
+
+
 @pytest.mark.asyncio
 async def test_stream(mcp_agent_tool, mock_mcp_client, alist):
     tool_use = {"toolUseId": "test-123", "name": "test_tool", "input": {"param": "value"}}

tests_integ/mcp/__init__.py

@@ -0,0 +1 @@
+"""MCP integration tests package."""

tests_integ/echo_server.py renamed to tests_integ/mcp/echo_server.py

@@ -15,9 +15,15 @@
     $ python echo_server.py
 """
 
-from typing import Any, Dict
-
 from mcp.server import FastMCP
+from pydantic import BaseModel
+
+
+class EchoResponse(BaseModel):
+    """Response model for echo with structured content."""
+
+    echoed: str
+    message_length: int
 
 
 def start_echo_server():
@@ -37,8 +43,8 @@ def echo(to_echo: str) -> str:
 
     # FastMCP automatically constructs structured output schema from method signature
     @mcp.tool(description="Echos response back with structured content", structured_output=True)
-    def echo_with_structured_content(to_echo: str) -> Dict[str, Any]:
-        return {"echoed": to_echo}
+    def echo_with_structured_content(to_echo: str) -> EchoResponse:
+        return EchoResponse(echoed=to_echo, message_length=len(to_echo))
 
     mcp.run(transport="stdio")
 

tests_integ/test_mcp_client.py renamed to tests_integ/mcp/test_mcp_client.py

@@ -75,7 +75,7 @@ def test_mcp_client():
 
     sse_mcp_client = MCPClient(lambda: sse_client("http://127.0.0.1:8000/sse"))
     stdio_mcp_client = MCPClient(
-        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/echo_server.py"]))
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
     )
 
     with sse_mcp_client, stdio_mcp_client:
@@ -161,7 +161,7 @@ def test_mcp_client():
 
 def test_can_reuse_mcp_client():
     stdio_mcp_client = MCPClient(
-        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/echo_server.py"]))
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
     )
     with stdio_mcp_client:
         stdio_mcp_client.list_tools_sync()
@@ -184,7 +184,7 @@ async def test_mcp_client_async_structured_content():
     that appears in structuredContent field.
     """
     stdio_mcp_client = MCPClient(
-        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/echo_server.py"]))
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
     )
 
     with stdio_mcp_client:
@@ -212,7 +212,7 @@ async def test_mcp_client_async_structured_content():
 def test_mcp_client_without_structured_content():
     """Test that MCP client works correctly when tools don't return structured content."""
     stdio_mcp_client = MCPClient(
-        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/echo_server.py"]))
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
     )
 
     with stdio_mcp_client:

tests_integ/test_mcp_client_structured_content_with_hooks.py renamed to tests_integ/mcp/test_mcp_client_structured_content_with_hooks.py

@@ -37,7 +37,7 @@ def test_mcp_client_hooks_structured_content():
 
     # Set up MCP client for echo server
     stdio_mcp_client = MCPClient(
-        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/echo_server.py"]))
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
     )
 
     with stdio_mcp_client:

tests_integ/mcp/test_mcp_output_schema.py

@@ -0,0 +1,44 @@
+"""Integration test for MCP tools with output schema."""
+
+from mcp import StdioServerParameters, stdio_client
+
+from strands.tools.mcp.mcp_client import MCPClient
+
+from .echo_server import EchoResponse
+
+
+def test_mcp_tool_output_schema():
+    """Test that MCP tools with output schema include it in tool spec."""
+    stdio_mcp_client = MCPClient(
+        lambda: stdio_client(StdioServerParameters(command="python", args=["tests_integ/mcp/echo_server.py"]))
+    )
+
+    with stdio_mcp_client:
+        tools = stdio_mcp_client.list_tools_sync()
+
+        # Find tools with and without output schema
+        echo_tool = next(tool for tool in tools if tool.tool_name == "echo")
+        structured_tool = next(tool for tool in tools if tool.tool_name == "echo_with_structured_content")
+
+        # Verify echo tool has no output schema
+        echo_spec = echo_tool.tool_spec
+        assert "outputSchema" not in echo_spec
+
+        # Verify structured tool has output schema
+        structured_spec = structured_tool.tool_spec
+        assert "outputSchema" in structured_spec
+
+        # Validate output schema matches expected structure
+        expected_schema = {
+            "description": "Response model for echo with structured content.",
+            "properties": {
+                "echoed": {"title": "Echoed", "type": "string"},
+                "message_length": {"title": "Message Length", "type": "integer"},
+            },
+            "required": ["echoed", "message_length"],
+            "title": "EchoResponse",
+            "type": "object",
+        }
+
+        assert structured_spec["outputSchema"]["json"] == expected_schema
+        assert structured_spec["outputSchema"]["json"] == EchoResponse.model_json_schema()