OverviewMicrosoft Security is moving toward an agentic future with Project Perception, where teams of AI agents autonomously defend customer environments against real, adaptive attackers. Shipping security agents that stay reliable at the speed the AI ecosystem evolves takes more than models. It takes an evaluation platform to measure how well agents detect, investigate, and respond, and to prove they are ready before they reach a security operations center. This role will help agent teams validate and hill-climb teams of agents against realistic adversaries, including simulated attack campaigns, threat scenarios, and adversarial red-team-style probes. The platform turns attacker behavior, telemetry, and agent trajectories into the signal product teams need to build at the frontier of AI. We build the harnesses, orchestration, and distributed infrastructure that put entire agentic defense systems under realistic attack, repeatedly and rigorously, so only agents that measurably improve security outcomes reach our customers. As a Principal Software Engineer, you will own the evaluation platform's architecture and technical direction. You will set direction for the team, make key engineering and architectural decisions, translate ambiguous problems into buildable systems, and raise the engineering bar across the group. In partnership with applied scientists, threat researchers, product managers, and engineers, you will turn security-evaluation needs into scalable, production-grade systems that determine what is ready to ship.Microsoft’s mission is to empower every person and every organization on the planet to achieve more. As employees we come together with a growth mindset, innovate to empower others, and collaborate to realize our shared goals. Each day we build on our values of respect, integrity, and accountability to create a culture of inclusion where everyone can thrive at work and beyond.ResponsibilitiesOwn the architecture and technical direction of the platform used to evaluate agent performance, guiding projects through the engineering lifecycle and ensuring the platform produces security-readiness signals that product teams trust.Design, build, and optimize the scalable algorithms, distributed systems, and services that power attack-simulation harnesses, agent orchestration, and data pipelines, with strong reliability, observability, and reproducibility.Lead validation of the platform and the defensive and offensive agent systems it measures, pinpoint weaknesses under adversarial conditions, drive solutions to complex technical challenges, and uphold standards for design, code quality, testing, and operational readiness.Build the APIs, tooling, and developer experience that enable product and research teams to onboard agents, run threat scenarios, and turn results into security-readiness gates and go or no-go decisions across heterogeneous technology stacks.Turn evaluation results into actionable engineering insights and strategic decisions that measurably improve how teams of agents defend against attackers.Set technical direction, mentor engineers, and drive cross-team alignment through ambiguity while communicating clearly and respectfully with partnersQualificationsRequired:Bachelor's Degree in Computer Science or related technical field AND 6+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, or Python OR equivalent experienceOther:Ability to meet Microsoft, customer and/or government security screening requirements are required for this role. These requirements include, but are not limited to the following specialized security screenings: Microsoft Cloud Background Check: This position will be required to pass the Microsoft background and Microsoft Cloud background check upon hire/transfer and every two years thereafter.Preferred:Master's Degree in Computer Science or related technical field AND 8+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, or Python OR Bachelor's Degree in Computer Science or related technical field AND 12+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, or Python OR equivalent experience.Experience building platforms for large language model-based or agentic systems, including orchestration frameworks, tool use, evaluation and testing harnesses, or machine learning infrastructure.Cybersecurity or adjacent experience in areas such as detection and response, security operations, threat intelligence, red teaming, AI safety, abuse or fraud prevention, or risk.Experience with event-driven architectures, high-throughput telemetry pipelines, or workflow orchestration engines. Software Engineering IC5 - The typical base pay range for this role across the U.S. is USD $142,800 - $274,800 per year. There is a different range applicable to specific work locations, within the San Francisco Bay area and New York City metropolitan area, and the base pay range for this role in those locations is USD $188,000 - $304,200 per year. Certain roles may be eligible for benefits and other compensation. Find additional benefits and pay information here:https://careers.microsoft.com/us/en/us-corporate-payThis position will be open for a minimum of 5 days, with applications accepted on an ongoing basis until the position is filled.Microsoft is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to age, ancestry, citizenship, color, family or medical care leave, gender identity or expression, genetic information, immigration status, marital status, medical condition, national origin, physical or mental disability, political affiliation, protected veteran or military status, race, ethnicity, religion, sex (including pregnancy), sexual orientation, or any other characteristic protected by applicable local laws, regulations and ordinances. If you need assistance with religious accommodations and/or a reasonable accommodation due to a disability during the application process, read more about requesting accommodations.