Principal Software Engineer

About the role

Overview AI agents are becoming part of how every organization works, and someone has to build the platform they run on. That's us. The Agent 365 Foundation team builds the shared infrastructure behind Microsoft's agent platform. Agents across Microsoft 365, Dynamics 365, Power Platform and beyond are deployed, secured, scaled and governed on what we build. We take on hard distributed-systems problems at real scale, and our decisions affect thousands of services and millions of customers. We're looking for a Principal Software Engineer who likes the problems nobody has solved yet. You question assumptions and break ambiguous challenges into clear bets. You can find the root cause behind a messy, multi-service failure. You'll help set the technical direction for the foundation that Microsoft's agent ecosystem runs on. 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. Team Specific Overview: The Agent 365 Shared Infrastructure & Foundation team builds the hosting, compute and platform services that agent workloads run on across Microsoft. We're building a fault-tolerant, cell-based architecture that lets teams ship fast, secure and compliant by default. Shared infrastructure gives us economies of scale. It also brings hard problems such as resource governance, noisy-neighbor isolation, multi-region expansion and sovereign-cloud boundaries. Our goal is 99.99% reliability for thousands of services, with best practices built in from day one. 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.

Responsibilities Leverage AI to build agentic engineering loops. Set technical direction. Own the architecture for core parts of the Agent 365 platform. Make the hard calls on trade-offs between scale, reliability, cost and speed, and take a long-term view. Solve the hardest problems. Lead the toughest cross-service investigations in high-throughput, multi-tenant systems, from first signal to lasting fix. Use data and first-principles thinking rather than assumptions. Build for scale and resilience. Design and deliver cell-based, fault-tolerant systems with Azure (AKS and related compute) that keep reliability, security and compliance high as we grow. Raise the engineering bar. Set standards for design, code quality, testing and operational excellence, and lead by example through design reviews, incident retrospectives and hands-on work. Lead across boundaries. Line up partner teams across M365, Dynamics 365, Power Platform and Azure on shared platform direction. Turn ambiguity into clear plans that teams can execute. Grow engineers. Mentor senior engineers and help build a culture of curiosity, healthy debate and ownership.