AI coding agents produce working code. Reviewing that code is the bottleneck.

Agents generate large, monolithic diffs - 40 files across schemas, business logic, and UI in a single pull request. The code might work. But a reviewer cannot assess intent or catch regressions in a wall of changes. Teams either slow down to review everything or rubber-stamp the PR. Neither scales.

Stacked pull requests solve this structurally. Break a feature into a chain of small, dependent PRs where each layer builds on the one below. Reviewers see only the diff for their layer. Google's Gerrit and Meta's Phabricator proved this pattern over a decade ago. Startups like Graphite built profitable businesses bringing it to GitHub. This is a solved problem.

What changed: GitHub shipped it natively on April 13, 2026. That matters because GitHub is where AI-assisted engineering lives. Copilot, Claude Code, Cursor, Windsurf, Gemini CLI - the dominant coding agents all target GitHub as their primary integration surface. A first-party stacked PR implementation on the platform where agents already operate removes a layer of tooling friction that kept stacked workflows niche.

The release also includes something the third-party tools do not: a SKILL.md file that teaches AI agents how to plan, decompose, and execute stacked workflows autonomously. It encodes specific patterns - plan dependency chains before writing code, place foundational changes in lower branches, run every command non-interactively with flags that prevent hanging on interactive prompts, stage files deliberately rather than bulk-committing. This mirrors what developers on r/ExperiencedDevs have been building manually with FEATURE_PLAN.md files - but formalized and portable across 20-plus agent platforms through the npx skills framework.

Caveats apply. The feature is in private preview. The CLI is at v0.0.1. Stack manipulation is limited. Graphite still leads on merge queues, stack reordering, and maturity. Hacker News response has been cautiously positive, with Phabricator veterans noting GitHub is a decade late.

Being late might be the point. GitHub did not need to invent stacked PRs. It needed to make them available where agents already work. Whether that changes daily practice depends on how the tooling matures, but the positioning is hard to ignore.