Tsong-kha-pa. The Great Treatise On The Stages Of The Path To Enlightenment Vol 1 (p. 222) defines the karma of lying as follow:
The 'eight bases' of lying are that seen, that heard, that
distinguished, and that cognized, as well as the four opposites of
these [that not seen, etc.]. Lying is when someone else-the recipient
of the lie-comprehends comprehends the meaning of the lie.
The 'discrimination' includes misrepresenting a perception, such as
what you have seen, as something you have not seen, or misrepresenting
what you have not seen as something you have seen.
The 'afflictions' are the three mental poisons.
The 'motivation' is your desire to misrepresent your perception.
The 'performance' is indicating something through speaking, through
choosing not to speak, or through gesture.
It is said that even causing others to engage in the three types of
speech-lying, divisive speech, or offensive speech-is the same as
doing it yourself.
The culmination of a lie is someone else's comprehension.
If you tell a lie without being motivated by any of the three poisons: the karmic path is not complete. Also the aspect of 'discrimination/perception' implies that if you say something false thinking it is true, the karmic path is not complete. For instance, if someone ask you "What time is it?", and you answer "it is seven" thinking it is indeed seven while in fact it is six, the karmic path [of lying] is not complete.
As for breaking a promise or a commitment, although the text does not state it, I infer that it is a karmic path of lying. This is so because my teacher said "if you have the intention to give something away, and so stop holding onto it as yours, but later come back on your intention or simply never give it away, its a karmic path of stealing".