A steward is an agent with one mission. It watches every PR and builds a focused backlog you can see and steer. It doesn't compete with the roadmap. It just owns its domain.
Cross-cutting work fails because it's everyone's job and nobody's priority. A steward owns one domain end-to-end — it doesn't file tickets or leave comments, it writes the code and opens the PR.
One mission means every PR gets a high-signal assessment in that domain. A narrow contribution zone means small, focused PRs that merge fast — not sprawling changesets that sit in review.
Install the GitHub App. That's it. You and your team keep working exactly as you do today. Reviews appear on your PRs, follow-up PRs appear in your repo.