6 Git history: The product's memory
This chapter covers
- The git log: the product history no changelog records
- Using AI to roll thousands of commits up into clear eras
- Having AI profile the top contributors behind each era
- Surfacing the features a team built, then quietly deleted, with AI
Chapter 5 described a product as it stands today; this chapter shows you how it got there. A codebase's git log records the work that made the current product possible: pivots that worked, bets that didn't, and features that have since been deleted—details that rarely survive in the README.
The story in the git log is often the one marketing never tells. On November 7, 2018, a developer on the Ghost team committed 28 lines of code titled "Created members auth middleware" (we'll omit decorative prefixes from commit messages throughout this chapter). That single commit kicked off Ghost's pivot from a WordPress alternative to a Substack competitor. The members/ directory it created grew over the next three years to dominate the repository, reshaping the product around paid newsletters. The pivot was never announced, and the README didn't change for years. The only way to see it coming was to read the commits.