Senior Staff Engineer – Agentic Engineering

Marathon Health is a leading advanced primary care provider, partnering with employer and union plan sponsors to improve health for millions of Americans. With nationwide onsite, nearsite, and network health centers, and virtual primary care, Marathon delivers a value-based model that enhances the healthcare experience for members and providers, while driving meaningful cost savings for plan sponsors. Marathon is proud to be certified as a Great Place to Work®, reflecting the company's commitment to building an inclusive, high-trust culture where all employees can thrive. Learn more at ABOUT THE JOB The Senior Staff Engineer is one of Marathon Health ’s most senior individual contributors and serves as the engineering organization’s center of gravity for excellence in agent-assisted software development. The Senior Staff Engineer combines hands-on technical delivery with broad organizational influence, using coding agents and modern agentic engineering practices to ship better software, faster, and to raise the engineering bar across Marathon’s technology organization. This role partners with engineering and product leadership to shape both what gets built and how it gets built, drives architectural decisions that span team boundaries, defines reusable engineering patterns, and grows agentic and AI-native engineering fluency across Engineering, Data, and Infrastructure. The Senior Staff Engineeroperateswith significant autonomy on initiatives that cross organizational lines and translates the rapidly evolving practice of building software with agents into patterns and habits Marathon’s engineers can apply in daily work. ESSENTIAL DUTIES & RESPONSIBILITIES - Deliver cross-cutting engineering work — platform components, refactors, integrations, and high-leverage features — at a pace achievable only through disciplined use of coding agents (Claude Code, Codex, or comparable) and modern agentic engineering practices. - Set the technicalstandardfor the engineering organization. Define and codify what good agentic engineering looks like at Marathon, including spec-driven development workflows, agent steering documents, custom Skills, MCP server patterns, subagent orchestration, and disciplined context engineering. Package these as reusable skills, plugins, templates, and internal documentation that other engineers can adopt without reinventing them. - Drive architectural decisions that span Engineering, Data, and Infrastructure. Partner with the Principal Architect and engineering leadership on systems design problems that cross team boundaries, lead ARB-level reviews, and bring strong fundamentals to APIdesign, distributed systems, event-driven patterns, observability, and security within a HIPAA-regulated environment. - Build internal agents, MCP integrations, and RAG-backed applications where the return on investment is clear. Apply agent development frameworks pragmatically, withappropriate evaluation, guardrails, and cost discipline. - Influence both what gets built and how it gets built. Partner directly with engineering leaders, product partners, and internal stakeholders to shape initiative scoping, sequencing, and tradeoff decisions. Bring product judgment and technical discernment upstream into the question of whether a problemwarrantsengineering investment — not just downstream into how the work is delivered. - Mentor senior and staff-level engineers across the organization. Lead pairing sessions, design reviews, andbrown-bags. Grow agentic and AI-native engineering fluency across Engineering, Data, and Infrastructure through hands-on collaboration and visibleexample. - Operate as a healthcare-aware engineer. Respect PHI handling, BAA requirements, audit trails, clinical safety considerations, and regulated change management, and help teams move efficiently within these requirements. QUALIFICATIONS - BS or MS in Computer Science or related field, or equivalent professional experience. - 1