Add story-style examples suite (27 stories + harness + CI) (#2957)

examples/stories/roots/server.py

@@ -0,0 +1,19 @@
+"""Roots primitive: a tool asks the client which filesystem roots it may use."""
+
+from mcp.server.mcpserver import Context, MCPServer
+from stories._hosting import run_server_from_args
+
+
+def build_server() -> MCPServer:
+    mcp = MCPServer("roots-example")
+
+    @mcp.tool(description="Return the filesystem roots the client has exposed.")
+    async def show_roots(ctx: Context) -> str:
+        result = await ctx.session.list_roots()  # pyright: ignore[reportDeprecated]
+        return "\n".join(f"{root.uri} ({root.name or 'unnamed'})" for root in result.roots)
+
+    return mcp
+
+
+if __name__ == "__main__":
+    run_server_from_args(build_server)