| Capitalize the commit message because ... Sometimes commit message deserves to be moderately long, like a paragraph or more. If one did not reference a code review or issue tracker link, for example, the need would likely be common. Even with an issue tracker there's value in capturing a few sentences of detail and sometimes more in the commit. By capitalizing the commit message, it is natural to extend it from a single sentence phrase to a paragraph with an introductory sentence. I think of commit messages as analogous to JavaDoc where the first sentence or first line is taken as the subject, or like a document with a heading. It would be silly for short commit messages not to use capitalization while long do. A capitalized message works as a short description of the intro to a paragraph. Generally. once you're writing more than a single standalone sentence, capitalize. In a permanent medium where it can be either one, also capitalize. A capitalized sentence or sentence fragment works in many contexts, like within a document or email. It would be annoying to convert going back and forth. Lastly, commit messages can sometimes act as names or proper nouns, and capitalization reinforces that role. Capitalization looks better as project or item headers in an issue tracker, and so to the extent that commits follow items, it's nice to consistently capitalize. Capitalize commit messages because when Git tools generate commit messages, they generate capitalized ones. (Be consistent.) I grok not capitalizing IM or IRC or other chat conversations, though I do if I start writing messages longer than a sentence. For everything but IM, capitalization constitutes the norm and good professional style. This rationale might not be entirely satisfying, because why does English have capitalization to begin with? That's a linguistic question I don't know the answer to. However, I do know that the norms that lead to sentence capitalization also apply to commit messages and code documentation Not capitalizing them feels like refusing to capitalize any other writing: a potential distraction from the content. |