Here's something in Thanissaro Bhikkhu's "The Buddhist Monastic Code" that addresses "intention." Emphasis mine.
Offenses. In analyzing offenses for the purpose of determining penalties, the Vibhaṅga divides an action into five factors: the effort, the perception under which it is made, the intention motivating it, the object at which it is aimed, and the result. In some of the rules, all five factors play a role in determining what is and is not a full offense. In others, only two, three, or four play a role. For example, under the pārājika rule forbidding murder, all five factors have to be present for a full offense: The object has to be a human being, the bhikkhu has to perceive him/her as a living being, he has to have murderous intent, he has to make an effort for the person to die, and the person has to die.
If any of these factors is missing, the penalty changes. For instance, object: If the bhikkhu kills a dog, the penalty is a pācittiya. Perception: If he cremates a friend, thinking that the friend is dead, then even if the friend is actually alive but severely comatose, the bhikkhu incurs no penalty. Intention: If he accidentally drops a rock on a person standing below him, he incurs no penalty even if the person dies. Effort: If he sees a person fall into the river but makes no effort to save the person, he incurs no penalty even if the person drowns. Result: If he tries to kill a person, but only succeeds in injuring him, he incurs a thullaccaya.
In some rules, though, the factors of intention, perception, and result do not make any difference in determining offenses. For example, if a bhikkhu is sleeping alone in a room and a woman comes in and lies down in the room with him, he incurs the pācittiya for lying down in the same lodging as a woman even though his intention was to lie down alone and he was unaware of her presence. A bhikkhu who drinks a glass of wine, thinking it to be grape juice, incurs the pācittiya for taking an intoxicant all the same. A bhikkhu who tries to frighten another bhikkhu incurs a pācittiya regardless of whether the other bhikkhu is actually frightened.
Of these factors, intention is the most variable. Under some rules, it deals simply with the issue of whether the bhikkhu's action was fully deliberate. In others, it deals with the impulse, the mental state, e.g., anger or lust, impelling his action. In others, it deals with the immediate aim of this action; in others, with the underlying motive that the immediate aim is intended to serve. In still others, it deals with combinations of any of these four.
Another variation is that in rules where a bhikkhu may be put into a passive role in committing an act that would fulfill the factor of effort, the factor of intention is changed to consent: mental acquiescence to the act combined with a physical or verbal expression of that acquiescence. Under some rules, such as the rule against sexual intercourse, simply letting the act happen counts as physical acquiescence even if one lies perfectly still, and the question of whether one incurs a penalty depends entirely on the state of one's mind. Under other rules, though — such as the rule against lustful contact with a woman, which includes cases where the woman is the agent making the contact — simply lying still is not enough to count as a physical sign of acquiescence, and even if one consents mentally, say, to a woman's fondling, one would incur a penalty only if one says something or responds with a physical movement to her action.
Because of the many variations possible in the factor of intention, it might be argued that it should be consistently divided into such sub-factors as presence or absence of deliberation, impulse, immediate aim, and motive. However, the Vibhaṅga itself is not consistent in distinguishing among these three. Under Pr 3 and Sg 1, for instance, it clearly distinguishes among them, in that impulse and motive play no part in determining the offense in question, whereas deliberation and immediate aim do. Under Sg 8 and 9, however, the impulse — anger — is conflated under motive: the desire to see another bhikkhu expelled from the Saṅgha. In fact, under most rules the Vibhaṅga does not make a clear distinction among these sub-factors, so it seems artificial to force a consistent distinction throughout. Thus the approach followed here is to place these considerations under one heading — intention — and to alert the reader to the distinctions among them only when important...
...Although it may seem harsh to impose penalties for unintentional actions, we must again reflect on the state of mind that leads to such actions. In some acts, of course, the intention makes all the difference between guilt and innocence. Taking an article with intent to return it, for example, is something else entirely from taking it with intent to steal. There are, however, other acts with damaging consequences that, when performed unintentionally, reveal carelessness and lack of circumspection in areas where a person may reasonably be held responsible. Many of the rules dealing with the proper care of Community property and one's basic requisites fall in this category. Except for one very unlikely situation, though, none of the major rules carry a penalty if broken unintentionally, while the minor rules that do carry such penalties may be regarded as useful lessons in mindfulness.