Ranking Engineer Agent (REA): The Autonomous AI Agent Accelerating Meta’s Ads Ranking Innovation

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Introduced the Ranking Engineer Agent (REA), an autonomous AI agent designed to drive the end-to-end ML lifecycle for ads ranking models. REA addresses long-horizon, asynchronous workflow autonomy via a hibernate-and-wake mechanism, high-quality/diverse hypothesis generation using a dual-source engine (historical insights database and ML research agent), and resilient execution within real-world constraints through a three-phase planning framework (Validation, Combination, Exploitation). REA's architecture comprises REA Planner and REA Executor, supported by a Skill, Knowledge and Tool System. In its first production rollout, REA achieved 2x model accuracy and 5x engineering output.