The Forward Deployed Engineer, Voice AI Agent Engineering designs, builds, ships, and operates voice AI agents whose core behavior is model-driven rather than explicitly authored - conversational and agentic experiences that interpret caller intent over a live audio channel, reason over context, invoke tools, and act on the caller''s behalf. Ability to build measurable frameworks assessing call quality, agent behavior, tool-selection accuracy, and regression risk - golden call datasets, scenario suites, model-as-judge scoring with human QA calibration, continuous evaluation pipelines, and drift detection - plus adversarial, jailbreak, and grounding testing.