multimodal models Jobs

Sierra is seeking a Research Engineer to join its Applied Research team, focused on advancing the quality, speed, and cost-efficiency of AI agents. This role involves pushing the boundaries of post-training, voice AI, and long-horizon task execution to build agents that can reason, adapt, and reliably perform complex tasks. You will determine the optimal approach for model development, balancing quality, speed, and cost to deliver customer value, and translate ambiguous product and customer problems into well-defined machine learning challenges. The position requires developing, fine-tuning, evaluating, and deploying models, advancing post-training techniques, and building rigorous evaluations to link model performance with real-world agent quality. You will work with large-scale, proprietary text and audio datasets and collaborate across teams to bring ideas from experimentation to production.