chore: import upstream snapshot with attribution

examples/snippets/servers/direct_call_tool_result.py

@@ -0,0 +1,42 @@
+"""Example showing direct CallToolResult return for advanced control."""
+
+from typing import Annotated
+
+from mcp_types import CallToolResult, TextContent
+from pydantic import BaseModel
+
+from mcp.server.mcpserver import MCPServer
+
+mcp = MCPServer("CallToolResult Example")
+
+
+class ValidationModel(BaseModel):
+    """Model for validating structured output."""
+
+    status: str
+    data: dict[str, int]
+
+
+@mcp.tool()
+def advanced_tool() -> CallToolResult:
+    """Return CallToolResult directly for full control including _meta field."""
+    return CallToolResult(
+        content=[TextContent(type="text", text="Response visible to the model")],
+        _meta={"hidden": "data for client applications only"},
+    )
+
+
+@mcp.tool()
+def validated_tool() -> Annotated[CallToolResult, ValidationModel]:
+    """Return CallToolResult with structured output validation."""
+    return CallToolResult(
+        content=[TextContent(type="text", text="Validated response")],
+        structured_content={"status": "success", "data": {"result": 42}},
+        _meta={"internal": "metadata"},
+    )
+
+
+@mcp.tool()
+def empty_result_tool() -> CallToolResult:
+    """For empty results, return CallToolResult with empty content."""
+    return CallToolResult(content=[])