diff --git a/python/utils/OpaqueArguments.h b/python/utils/OpaqueArguments.h
index 46afd2fedc8..7f88473df58 100644
--- a/python/utils/OpaqueArguments.h
+++ b/python/utils/OpaqueArguments.h
@@ -99,6 +99,14 @@ inline py::args simplifiedValidateInputArguments(py::args &args) {
       if (shape.size() != 1)
         throw std::runtime_error("Cannot pass ndarray with shape != (N,).");
 
+      // Vector size validation
+      size_t size = shape[0].cast<size_t>();
+      if (size == 0 || (size & (size - 1)) != 0) {
+        throw std::invalid_argument(fmt::format(
+            "Invalid vector size: {}. Vector size must be a power of 2.",
+            size));
+      }
+
       arg = args[i].attr("tolist")();
     } else if (py::isinstance<py::str>(arg)) {
       arg = py::cast<std::string>(arg);
diff --git a/runtime/cudaq/algorithms/observe.h b/runtime/cudaq/algorithms/observe.h
index 407a528013a..dfaa7c93414 100644
--- a/runtime/cudaq/algorithms/observe.h
+++ b/runtime/cudaq/algorithms/observe.h
@@ -59,9 +59,9 @@ concept ObserveCallValid =
 /// @param shots number of shots to run for the given kernel, or -1 if not
 /// applicable.
 /// @param noise noise model to use for the sample operation
-/// @param num_trajectories is the optional number of trajectories to be used when
-/// computing the expectation values in the presence of noise. This parameter is
-/// only applied to simulation backends that support noisy
+/// @param num_trajectories is the optional number of trajectories to be used
+/// when computing the expectation values in the presence of noise. This
+/// parameter is only applied to simulation backends that support noisy
 /// simulation of trajectories.
 struct observe_options {
   int shots = -1;