Commit-editmsg -

If you have ever typed git commit without the -m flag, you have interacted with this file. You might have thought you were just using a text editor to write a message. In reality, you were editing a temporary file named COMMIT-EDITMSG .

Now, if a developer tries to commit with a bad message, Git aborts. This doesn't just work for command-line commits; it works for GUI tools and IDEs because everything eventually writes to COMMIT-EDITMSG . Your project uses Jira (PROJ-123). You want every commit to include the ticket number, but you hate typing it. 30 seconds before you commit, you fetched the PROJ-123 branch. COMMIT-EDITMSG

Understanding this file transforms you from a casual Git user into a Git power user. It is the gateway to crafting perfect commit history, automating quality checks, and integrating seamlessly with modern AI tooling. The COMMIT-EDITMSG file is a transient, temporary file created by Git in the .git/ directory (specifically, .git/COMMIT_EDITMSG ) whenever you initiate a commit that requires an editor. Its sole purpose is to hold the commit message for the commit currently in progress. If you have ever typed git commit without

git commit -m "Fix bug in login flow" The -m flag is convenient for short messages, but it completely bypasses the COMMIT-EDITMSG workflow. This means you also bypass the powerful features that come with it: templates, hook validation, and multi-line editing. To truly appreciate the file, let's walk through a manual commit. Imagine you have staged changes. You run git commit . Your editor opens, and you see something like this: Now, if a developer tries to commit with

Located in .git/hooks/commit-msg (or .git/hooks/commit-msg.sample to start), this script can read, validate, or even modify the COMMIT-EDITMSG file before the commit is finalized. You want every commit message to follow the Conventional Commits standard (e.g., feat: add login , fix: resolve null pointer ).

Using a prepare-commit-msg hook (a cousin that runs before the editor opens), you can read the branch name and append the ticket to COMMIT-EDITMSG :