feat(mcp_client): Implement ExternalMCPManager and StdioMCPServer with tests

tests/test_external_mcp.py

@@ -0,0 +1,55 @@
+import asyncio
+import json
+import sys
+import pytest
+from src import mcp_client
+from src import models
+
+@pytest.mark.asyncio
+async def test_external_mcp_real_process():
+    manager = mcp_client.ExternalMCPManager()
+    
+    # Use our mock script
+    mock_script = "scripts/mock_mcp_server.py"
+    config = models.MCPServerConfig(
+        name="real-mock", 
+        command="python", 
+        args=[mock_script]
+    )
+    
+    await manager.add_server(config)
+    
+    try:
+        tools = manager.get_all_tools()
+        assert "echo" in tools
+        assert tools["echo"]["server"] == "real-mock"
+        
+        result = await manager.async_dispatch("echo", {"hello": "world"})
+        assert "ECHO: {'hello': 'world'}" in result
+    finally:
+        await manager.stop_all()
+
+@pytest.mark.asyncio
+async def test_get_tool_schemas_includes_external():
+    manager = mcp_client.get_external_mcp_manager()
+    # Reset manager
+    await manager.stop_all()
+    
+    mock_script = "scripts/mock_mcp_server.py"
+    config = models.MCPServerConfig(
+        name="test-server", 
+        command="python", 
+        args=[mock_script]
+    )
+    
+    await manager.add_server(config)
+    
+    try:
+        schemas = mcp_client.get_tool_schemas()
+        echo_schema = next((s for s in schemas if s["name"] == "echo"), None)
+        
+        assert echo_schema is not None
+        assert echo_schema["description"] == "Echo input"
+        assert echo_schema["parameters"] == {"type": "object"}
+    finally:
+        await manager.stop_all()