Why Trunk-Based Development Suits Small AI Teams
AI features change in small, frequent steps: a prompt adjustment, a new tool, a different retrieval setting. When each of those lives on its own branch for two weeks, the changes meet for the first time on merge day, and nobody can tell which one broke the answers.
Trunk-based development means everyone merges small changes into the main branch at least once a day, with unfinished work hidden behind flags.
The case for it
Changes get tested together early. A prompt change and a retrieval change affect each other. Merging both into main daily means your evaluations see the real combination, not two versions that each looked fine alone.
Problems are easier to trace. When quality drops, a day of small commits is easy to search. A merge of three weeks of work is not.
Fewer painful conflicts. Prompt files and configuration are edited by many people. Short branches keep conflicts small.
Faster feedback. Small changes can reach internal users the same day, behind a flag.
What it requires
- A fast pipeline. If CI takes an hour, people batch their changes. Keep the main checks under 15 minutes and run heavy evaluations on a schedule.
- Feature flags. Incomplete features merge but stay switched off.
- Evaluation gates. Merges to main have to be safe, so an automated quality check runs on every change.
- Quick reviews. Small pull requests reviewed within hours, not days.
- Good monitoring. Frequent small releases need dashboards that show quickly whether a change hurt quality, latency or cost.
The strongest objection
"Our experiments take weeks, so they can't live on main." Experiments can still use branches, notebooks or separate repositories. The rule applies to changes headed for production. Once an experiment becomes a feature, its production code should arrive in small merges.
Getting started
- Agree a maximum branch age, such as two days.
- Add a flag service if you don't have one.
- Make the evaluation job run on every pull request.
- Track branch lifetimes for a month and discuss the numbers as a team.
Most small teams notice fewer painful merges within a few weeks.