If you want PSI, though, there are some ground rules. The character can use PSI in as many ways as they have PSI points, and those ways are declared when making the character. So a character with a PSI of 4 might have Telepathy (PSI+Communications), Stun (PSI+Fist), Psychometry (PSI+Humanities), and Suggestion (PSI+Persuade). Note that skill use is limited to two ranks, unless the character specifically takes a Psionic Specialty - i.e. Communications+2 (Specialty Telepathy+4). Also, the character uses PSI points to power the ability, so it is a resource, renewable per session.