Cattāri Brahmavihārā

I woke up feeling ill and unwell and suspect it has to do with my having formulated an intention yesterday that came close to breaking a precept. As a result, I wanted to get some clarity on how a precept is actually broken. I found the following and thought it might be of interest:

Briefly, how many ways are there of breaking the eight Uposatha precepts?There are two ways: by body and by speech.

In all of the eight, if one breaks a precept, then it is done bodily. If one orders another to do so, then the precept is broken through speech. This (speech) must be accompanied by intention before the precept is broken, but this is true for the first and second precepts only; for the third to the eighth precept, even if one asks another to do so, one does not break the precept.

Breaking a precept through one’s own effort is known as sahatthikapayoga. The ordering of another to behave in a way that breaks a precept is called anattikapayoga.

Thus one who is careful and does not stray from the precepts is known as a virtuous person. The wise say that sila, or keeping precepts, is an instrument by which body and speech can be purified. It is a way to vanquish the coarse defilements which appear through body and speech.

https://www.accesstoinsight.org/lib/authors/nanavara/uposatha.html

In terms of specific breaches of precepts I was able to find the following:

https://www.bhantedhammika.net/good-question-good-answer/4-the-five-precepts

http://sdhammika.blogspot.com/2008/08/third-precept.html