A release manager agent acts as the merge gate. It checks that all required approvals are present, CI is green, and no blocking labels are set before merging a PR and tagging a release. In Fleet's reactive chain, the release manager fires after a reviewer (tech-lead, qa-lead/engineer, or pr-reviewer) publishes the pr_approved fabric event.
The role-specific prompt encodes your merge policy: what counts as a valid approval when your CI is configured with spending limits, how to handle hotfixes, and what post-merge steps (changelog update, version bump, deploy trigger) are expected. A generic agent will merge when GitHub's API says it can; a release manager agent enforces the policy layer on top of that.