Vaguely disappointing. Maybe it's the fault of the short length; there's just not enough time to develop characters and background to my satisfaction. I remember now why I avoid short stories.
A lowly spacer has charge of the ship's cat, which has been genetically modified for intelligence and secretly has developed telepathic communication. The ship has stopped at a distant planet where they are trying to establish trade with an alien race. Very predictably, the cat saves the day and wins it's ship the contract by killing a species of vermin plaguing the aliens.