test: cover typed empty struct for omitted tool arguments

Verify zero-parameter tools using struct input types also succeed when
clients omit the arguments field entirely.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: advancedresearcharray

pkg/inventory/server_tool_test.go

@@ -126,3 +126,32 @@ func TestNewServerToolWithContextHandler_EmptyArguments_TreatedAsEmptyObject(t *
 		})
 	}
 }
+
+func TestNewServerToolWithContextHandler_EmptyArguments_TypedEmptyStruct(t *testing.T) {
+	type emptyArgs struct{}
+
+	tool := NewServerToolWithContextHandler(
+		mcp.Tool{Name: "typed_zero_arg_tool"},
+		testToolsetMetadata("test"),
+		func(_ context.Context, _ *mcp.CallToolRequest, args emptyArgs) (*mcp.CallToolResult, any, error) {
+			return &mcp.CallToolResult{
+				Content: []mcp.Content{
+					&mcp.TextContent{Text: "ok"},
+				},
+			}, args, nil
+		},
+	)
+
+	handler := tool.HandlerFunc(nil)
+
+	result, err := handler(context.Background(), &mcp.CallToolRequest{
+		Params: &mcp.CallToolParamsRaw{
+			Name:      "typed_zero_arg_tool",
+			Arguments: nil,
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	assert.False(t, result.IsError)
+}