GitHub put stacked pull requests into public preview on 30 July.
A stack is a chain of dependent PRs, each reviewed on top of the one before it, so a large change arrives as a sequence of small readable steps instead of one enormous diff.
Why this arrives now
Stacking is an old idea — it has existed outside GitHub for years. What changed is the size of the average change.
When an agent implements a feature, it does not naturally stop at a reviewable boundary. It writes the migration, the model, the handler and the tests in one pass. That is one pull request nobody reads properly, and "nobody reads it properly" is where bugs enter.
What a stack buys you
- Each step can be approved and merged while later steps are still being written
- A reviewer holds one concern in mind at a time instead of four
- A rejected step is a small revert, not a lost week
Public preview, so treat it accordingly
Public preview means available to everyone and still subject to change. Try it on a real but non-critical piece of work first.
Pair it with Copilot code review, which reached GA with agent skills and MCP the day before, on 29 July. A small reviewable step is exactly the shape an automated reviewer handles best.