How to get prediction labels with Tensorflow Serving Predict API?

Question

I have a keras classification model saved remotely, and I use RESTful API to call the model on my site and make predictions. The JSON request is done as follows

URL:

POST https://my.site/models/v1:predict

JSON:

{"instances": [["...something useful to predict a label..."]]}

and what I obtain is of the form (one value for each label)

{
  "predictions": [
    [
      0.001
      0.832
      ...
      0.104
    ]
  ]
}

Is there a way to obtain also the label corresponding to each prediction probability? That is, to get something in the form

{
  "predictions": [
    [
      "label_1": 0.001
      "label_2": 0.832
      ...
      "label_n": 0.104
    ]
  ]
}

or

{
  "predictions": [
    [
      0.001
      0.832
      ...
      0.104
    ]
    [
      "label_1"
      "label_2"
      ...
      "label_n"
    ]
  ]
}

I read documentation about specifying signatures when exporting a model, which seems to be related to my question, but it is not very clear about what has to be done. Basically it consists of adding the argument signatures when saving the model:

@tf.function()
def my_predict(my_prediction_inputs):
    ...

my_signatures = my_predict.get_concrete_function(...)

tf.keras.models.save_model(model, path, signatures=my_signatures, ...)