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.