Repairs

Here is my example of an argument that needs to be repaired in some way:
No horse barks. So Cash does not bark.
Here is my analysis of the argument I stated above:
The only premise that needs to be added to the argument in order to make it a strong or valid argument is, “Cash is a horse.” If this sentence is added the argument becomes a good argument, since the proposed added sentence is a true premise.
Another premise “Cash nays” would not be added to the argument. Even though it is a true statement, and one that can be determined as obvious to the person making the argument, by adding it the argument does not become stronger or valid. It would violate the first rule of The Guide to Repairing Arguments.
What I noted from this particular example, is that it is important to be careful what premises you add to an argument to repair it; just because it is true does not make it a premise that improves the argument.