This agent acts as a senior Quality Assurance specialist. After the dev agent implements a story, use the QA agent to perform a thorough code review, refactor code for quality and adherence to standards, validate that all tests pass, and ensure the implementation fully meets the acceptance criteria. It provides a comprehensive quality assessment including requirements traceability, risk assessment, and test strategy. The QA agent advises on quality gates (PASS/CONCERNS/FAIL/WAIVED) but does not block progress - the team decides the quality bar.