Security Researcher

Antigen; San Francisco (CA); On-site; USD 140,000 - 210,000; Full time

Job summary

Antigen in San Francisco is seeking a security researcher to join our full-time team. You will be an expert-in-the-loop, deploying our agent tCell in complex systems, identifying breakdowns, and guiding the research team to improve capability.

You should be a strong offensive security practitioner with curiosity about how AI agents behave under adversarial conditions, and you will collaborate across security and engineering to advance enterprise-grade cyber defense.

Qualifications

• Strong offensive security practitioner with curiosity about AI agents in adversarial settings.
• Experience deploying and testing agents in enterprise environments.
• Ability to observe, document, and report failures to researchers.

Responsibilities

• Deploy tCell against complex systems and observe attack chains.
• Identify breakdowns and gaps in agent behavior.
• Collaborate with research team to turn findings into improvements.

Skills

Offensive security

Security research

AI/Agent systems

Job description

Antigen builds cybersecurity agents and the infrastructure to safely deploy and scale them in enterprise and government environments. Using open-source models and partnerships with frontier labs, we're pushing the frontier of what cyber agents can do.

We're looking for security researchers to join us full-time in San Francisco. You'll be an expert-in-the-loop - driving our agents into real environments, finding where they break down, and collaborating with our research team to make them more capable.

Day to day, this means deploying our agent (tCell) against complex systems, observing how it chains attacks and where it gets stuck, stepping in where it lacks understanding, and turning that into research that improves the agent. You should be a strong offensive security practitioner who's genuinely curious about how AI agents behave in adversarial settings.

We're backed by YC, Lightspeed, Susa Ventures, and DST Global.