A saved step

Think of it when you finish one small step that works, before you start the next.

In everyday life

A writer saves the novel under a new name after each chapter. If chapter 9 goes wrong, they open the chapter 8 file. A writer who saves once a day loses the whole day to one bad edit.

One case

A developer and an AI agent rework a music streaming app’s search page from 13:00 to 16:00 without a single commit. The search works at every check until 15:40, when one edit breaks it. Nobody can tell which of the 60 changed lines did it. The only saved version is from 13:00, so going back to it throws away 3 hours of work.

Three hours of working steps, and no save point
The case, cell by cell1 cell = 30 minutes
Newest version that works
13:0013:3014:0014:3015:0015:3015:30
Newest version saved in a commit
13:0013:0013:0013:0013:0013:0013:00
Work lost by going back
3 h
With a commit per step
30 min
The search broke at 15:40. A commit at 15:30 would have been a safe place to return to.

Every case

A commit is a point you can return to. Small commits, each one working, give you many such points and a short list of what changed between them. Large commits leave long gaps: when something breaks, you cannot tell which change did it, and going back costs everything since the last save. The message matters too. “fix” tells a future reader nothing; “Stop search from dropping accents” tells them why.

The word

Engineers call this

commitA saved snapshot of a project’s files, with a message that says what changed and why. Tools such as gitThe version control tool most teams use. It records every commit and branch of a project. keep the commits on each branch, so you can return to any of them.

Commit each small step that works, with a message that says why. Commit often enough that going back one commit costs little.

Where this idea leads

Skills that encode it

  • principle-sequence-verifiable-units pstackBreak work into small units that each end in a verifiable state, and stack commits in the order that proves the work.
  • technical-writing pstackSays commit messages are writing too, held to the same plain, clear sentences as docs.