A QA engineer agent reviews pull requests for test coverage gaps, writes missing tests, and runs acceptance checks against the test environment before a release is approved. It is a distinct role from a PR reviewer or tech lead: where the reviewer checks logic and style, the QA agent focuses on correctness, edge cases, and regression risk.
A role-specific prompt encodes your team's quality bar: which test types are mandatory, what coverage thresholds trigger a block, and how to categorize bugs by severity. A generic agent will write tests but may not enforce the policies that actually protect your release pipeline.