Member of Technical Staff, AI Researcher (New Stealth Startup)

The role

This person will design and build evaluation frameworks, reinforcement learning environments, and feedback systems for frontier AI. The role involves investigating how data and evaluations influence model behavior while building the necessary infrastructure and tools.

What you will do

• Design and build evaluation frameworks, benchmarks, and methodologies for frontier large language models, AI agents, multimodal models, and reinforcement learning environments
• Develop reward models, programmatic verifiers, graders, and other feedback systems
• Design and run controlled supervised fine-tuning and reinforcement learning experiments
• Research and define what makes evaluations representative of real-world work and operational environments
• Build systems for producing high-quality human data
• Translate research questions into lightweight, rigorous experiments
• Prototype quickly, evaluate results, diagnose failure modes, and convert findings into improved benchmarks, datasets, or technical systems
• Move promising methods from experimentation into scalable, production-quality implementations
• Work across research, engineering, product, and operations to advance a shared technical roadmap
• Contribute to the broader technical community through benchmarks, open-source tools, research, and technical writing

Required qualifications

• 5+ years of relevant experience in machine learning, artificial intelligence, computer science, data science, software engineering, or a related technical field
• Demonstrated ability to operate at the intersection of AI research and software engineering
• Strong Python skills and experience building reliable, scalable software
• Hands-on experience with AI agents, model evaluations, reinforcement learning, post-training, or related systems
• Strong understanding of frontier AI methods, including benchmarks, evaluation techniques, agent harnesses, post-training approaches, and training-data design
• Experience building or working with reward models, automated verifiers, graders, or other model-feedback systems
• Experience designing evaluations or experiments that measure model capability, generalization, alignment, or agent performance
• Ability to build research prototypes and develop them into maintainable, production-quality systems
• Strong analytical, problem-solving, written communication, and technical documentation skills
• U.S. citizenship is required

Nice to have

• An advanced degree in machine learning, artificial intelligence, computer science, data science, or a related field

Benefits

• Career track opportunity with potential for rapid advancement
• 100% employer paid, comprehensive health care including medical, dental, and vision for you and your family
• Paid maternity and paternity for 14 weeks at employees' normal pay
• Unlimited PTO, with management approval
• Opportunities for professional development and continued learning
• Optional 401K, FSA, and equity incentives available
• Mental health benefits are available through Tara Mind
• Cost effective GLP-1 solutions available through Crux

Before you apply

• U.S. citizenship is required

About the company

Red Cell Partners is an incubation firm building and investing in rapidly scalable technology-led companies in healthcare, cyber, and national security. They are launching a new stealth startup to redefine how mission-critical organizations adopt AI.