Member of Technical Staff - Agent Engineer

Phylo • South San Francisco, CA

10d • Hybrid

About The Position

Phylo is an applied research lab building agentic intelligence to accelerate discovery for every biomedical scientist. We believe AI agents will fundamentally transform how biomedical research is done. Our team brings together engineers, AI researchers, and scientists to build systems capable of carrying out complex scientific work. About the role We’re looking for an engineer with research or production experience in AI agents to build and evaluate systems that make our agents capable, reliable, and measurably better. The model is only one part of an agent; the harness shapes how it plans, uses tools, manages context, coordinates work, and recovers from failure. You will own these systems in production and build evaluations to measure whether changes improve performance. The work includes bringing the latest advances and original ideas into production. The ideal candidate combines strong engineering execution with a quantitative mindset and an interest in AI agents for scientific discovery.

Requirements

• Strong software engineering experience building production backend systems, infrastructure, or distributed systems.
• Research or production experience in machine learning, or another quantitative discipline.
• Familiarity with LLM APIs, tool calling, agent runtimes, or workflow orchestration.
• Strong quantitative judgment and the ability to determine whether an apparent improvement is real, reproducible, and meaningful.
• Ability to move between research questions, data analysis, system design, and production implementation.
• Experience or strong interest in AI for science, scientific agents, computational research, or automated scientific discovery.
• Experience working in AI-native teams that use coding agents or automation extensively.
• High ownership, clear communication, and strong engineering judgment.
• We care more about demonstrated ability than a particular credential.
• Relevant backgrounds may include ML or LLM engineering, academic research paired with substantial software development, scientific computing, or production systems engineering with demonstrated quantitative experience.

Nice To Haves

• Experience with LLM evaluations, human evaluation, model judges, replay testing, benchmark design, or experiment tracking.
• Experience applying classical machine learning methods alongside LLMs in production systems.
• Experience with task queues, event streams, Kubernetes, code sandboxes, or durable workflow systems.
• An advanced degree or equivalent experience in machine learning, computational biology, physics, applied mathematics, statistics, or a related field.

Responsibilities

• Advance the agent harness by bringing the latest research and open-source developments into production and experimenting with new approaches to multi-agent coordination, model routing, memory, planning, and tool use.
• Build rigorous evaluations that measure agent quality, reliability, latency, and cost on representative scientific tasks.
• Monitor agent quality in production, troubleshoot failures quickly in high-ambiguity situations, and translate findings into engineering improvements.
• Collaborate on reliable infrastructure for long-running sessions, safe sandboxed execution, background work, and subagents.
• Partner with scientists and engineers to evaluate and productionize new agent capabilities.

Benefits

• Competitive salary and equity share in building the future of biomedical discovery
• Full medical, dental, and vision coverage, including free therapy sessions and eyewear stipend
• 401(k) to help you build long-term financial security (US only)
• Unlimited PTO to recharge when you need it (US only)
• Lunch and snacks when you're in the office
• Regular team offsites and company events
• A culture of excellence and speed - we move fast, think big, and support each other every step of the way
• Your work will directly impact our mission to 100X biomedical discoveries through AI

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level