Popular cybernetic (or occasionally bioborg) implant, common among medium-tech biont clades, and those who like to do their own engineering and surgery. Nail-tools consist of telescoping, fractal micro-manipulators that extend from the ends of the user's regular digits.
On humanoid and similar bionts, they usually extend from underneath the individual's fingernails, and are tucked away underneath when not in use, hence the name. It takes considerable training to learn to handle the new sensory data and control the fine movements of the manipulators. However, in theory, a previously unaugmented baseline can do it, and many Su view it as a rite of passage of sorts. The manipulators have their own processing to interpret broad commands coming through the sophont's nervous system.