chore: import upstream snapshot with attribution

examples/stories/tools/server.py

@@ -0,0 +1,37 @@
+"""Tools primitive: register, list, call, structured output, annotations."""
+
+from typing import Literal
+
+from mcp_types import ToolAnnotations
+from pydantic import BaseModel
+
+from mcp.server.mcpserver import MCPServer
+from stories._hosting import run_server_from_args
+
+
+class CalcResult(BaseModel):
+    op: str
+    result: float
+
+
+def build_server() -> MCPServer:
+    mcp = MCPServer("tools-example")
+
+    @mcp.tool(
+        title="Calculator",
+        description="Apply an arithmetic operation to two numbers.",
+        annotations=ToolAnnotations(read_only_hint=True, idempotent_hint=True),
+    )
+    def calc(op: Literal["add", "sub", "mul"], a: float, b: float) -> CalcResult:
+        result = a + b if op == "add" else a - b if op == "sub" else a * b
+        return CalcResult(op=op, result=result)
+
+    @mcp.tool(description="Echo the input back as plain text.", structured_output=False)
+    def echo(text: str) -> str:
+        return text
+
+    return mcp
+
+
+if __name__ == "__main__":
+    run_server_from_args(build_server)