Hi @jmendezicce,
The challenge here is that the pipe size is an instance parameter.
Due to a limitation, the current versions of Autodesk Revit cannot add instance parameters to keynotes.
Please, vote for the following registered wish for a product enhancement here:
Keynotes with Instance Parameter Text Field
I would suggest to tag the pipes by category and defining a label which in the tag family, which reads the parameters you wish for.
I hope this information helps.
In order to point other users to the above registered wish for a product enhancement and to encourage participation on the related Revit Ideas voting, I will mark this post as a solution - your feedback or further questions or concerns are of course welcome anyways.
Please, feel free to let me know if you need further help.
Best regards,