There are many types of electronic or automotive tools that can help diagnose a problem, such as a volt-ohmmeter or an OBD scanner. There are different tools to help fix a problem, such as a soldering iron or a torque wrench.
The field of psychology has diagnostic instruments as well, such as the Stanford-Binet Intelligence Test.
Is there a word for a psychological instrument that not only diagnoses, but can help a subject improve? I was thinking of
a ?proscriptive instrument
(EDIT: Proscriptive is close wrong. A proscriptive tool would be a forbidden one.)
Here is an example. The Myers-Briggs personality inventory is a diagnostic test that will categorize you as, say, an Extroverted, iNtuitive, Thinking, Perceiving (ENTP) person. You may also use the results of the inventory as a _ (fill in the blank) tool to help you understand your own strengths and weaknesses (example) and work better with others.