Commit

If Git is the time machine, a commit is the button you press to actually save the moment.

A save point on its own is just a snapshot. A commit is that snapshot with a sticky note attached telling you what you changed and why. The note is the whole magic. Without it you've got a hundred unlabeled save points and no idea which one to jump back to.

So every commit is two things stapled together:

1. The snapshot. The exact state of every file at that instant, frozen.

2. The message. A short line you write describing what just happened.

The messages read like a journal of the work:

• "Added checkout button."
• "Fixed the typo on the homepage."
• "Broke everything, send help."

Scroll that list months later and you can read the entire story of how the thing got built, one entry at a time. Nobody's memory survives that long. The commit history does.

Write the note for future you, because future you is an idiot who forgot everything. I say that with love, I am that idiot constantly. A commit that just says "stuff" or "fixes" tells you nothing when you're staring at it in a panic at midnight. Compare:

• "stuff" → great, now you're opening twenty files to figure out what changed.
• "Fixed the bug where coupons applied twice" → you know exactly where to look the day it happens again.

One of those is a gift. The other is a shrug you mailed to yourself.

Here's why this matters the second AI enters the picture. When an agent builds something for you, it doesn't do it in one giant leap. It commits as it goes, little save point after little save point, each with its own note. So when it takes a wrong turn at 9am and you don't notice until 11, you haven't lost the morning. You roll back to the last good commit and pick up from there, like the bad two hours never happened.

And you barely lift a finger. Tools like Codex and Claude Code write the commits themselves while they work, message and all. You get a clean trail for free.

That trail has a sneaky second use. A detailed commit history is also the easiest weekly report you'll ever run. You don't sit down and try to remember what you did. You scroll Friday back to Monday and there it is, every change, every fix, timestamped, already written down.

A good commit isn't bookkeeping. It's a note you hand the version of you who has to come back here later and figure out what on earth past-you was thinking.