flaky
adj. (var sp. `flakey') Subject to frequent lossage.
This use is of course related to the common slang use of the word
to describe a person as eccentric, crazy, or just unreliable. A
system that is flaky is working, sort of --- enough that you are
tempted to try to use it --- but fails frequently enough that the
odds in favor of finishing what you start are low. Commonwealth
hackish prefers dodgy or wonky.