diff --git a/neuralnetworks/aidl/android/hardware/neuralnetworks/OperationType.aidl b/neuralnetworks/aidl/android/hardware/neuralnetworks/OperationType.aidl
index 88c61c34b7..04c15b9eb1 100644
--- a/neuralnetworks/aidl/android/hardware/neuralnetworks/OperationType.aidl
+++ b/neuralnetworks/aidl/android/hardware/neuralnetworks/OperationType.aidl
@@ -5223,6 +5223,18 @@ enum OperationType {
     /**
      * Pads a tensor with mirrored values.
      *
+     * This operator specifies one of two padding modes: REFLECT or SYMMETRIC.
+     * In the case of REFLECT mode, the mirroring excludes the border element
+     * on the padding side.
+     * In the case of SYMMETRIC mode, the mirroring includes the border element
+     * on the padding side.
+     *
+     * For example, if the input is the 1-D tensor `[1, 2, 3]` and the padding
+     * is `[0, 2]` (i.e., pad no elements before the first (and only) dimension,
+     * and two elements after the first (and only) dimension), then:
+     *     - REFLECT mode produces the output `[1, 2, 3, 2, 1]`
+     *     - SYMMETRIC mode produces the output `[1, 2, 3, 3, 2]`
+     *
      * Supported tensor {@link OperandType}:
      * * {@link OperandType::TENSOR_FLOAT16}
      * * {@link OperandType::TENSOR_FLOAT32}
@@ -5241,6 +5253,11 @@ enum OperationType {
      *      front of dimension i.
      *      padding[i, 1] specifies the number of elements to be padded after the
      *      end of dimension i.
+     *      Each padding value must be nonnegative.
+     *      In the case of REFLECT mode, each padding value must be less than the
+     *      corresponding dimension.
+     *      In the case of SYMMETRIC mode, each padding value must be less than or
+     *      equal to the corresponding dimension.
      * * 2: An {@link OperandType::INT32} scalar, specifying the mode.
      *      Options are 0:REFLECT and 1:SYMMETRIC.
      *