Principal Engineer - MCP or ACP Layer (API & AI Orchestration)

Join ABC Fitness and become part of a culture that’s as ambitious as it is authentic. Let’s transform the future of fitness—together!

Our Values

Best Life We believe great work begins with great people. That’s why our culture is built on respect, trust, and belonging. We create an inclusive environment where every team member can bring their authentic self to work—because diverse perspectives drive innovation and meaningful impact.

Growth Mindset We are doers, thinkers, and dreamers. At ABC Fitness, your growth is our investment. Through continuous learning, mentorship, and professional development opportunities, we empower you to reach new heights—personally and professionally.

One Team From day one, you’ll be part of a team that collaborates, celebrates, and cares. We move fast, support one another, and have fun along the way. Because when you thrive, we all thrive.

We’re looking for a senior individual contributor who can independently lead delivery of an LLM feature area, including eval strategy and production readiness. What You’ll Do

• Architect, build, and evolve the MCP / ACP ecosystem that exposes ABC Fitness capabilities as standardized, agent-consumable tools.
• Design schemas, tool definitions, and abstraction layers that shield AI agents from the complexity and inconsistency of underlying systems while providing clean, structured, hallucination-resistant interfaces.
• Define and implement reusable orchestration patterns for multi-step AI workflows, including tool use, validation, retries, state management, fallback handling, and long-running execution flows.
• Build for deterministic execution by ensuring AI-driven tool interactions are predictable, safe, observable, auditable, and reversible where necessary.
• Establish company-wide standards for AI interaction patterns, structured outputs, input/output validation, schema governance, and agent orchestration workflows.
• Design and implement security, permissions, and access control patterns specifically for non-human actors and autonomous systems, including auditability, rate controls, and operational boundaries.
• Build instrumentation and observability capabilities that trace agent interactions, identify schema friction, measure execution quality, and improve orchestration success rates over time.
• Partner closely with API modernization, platform engineering, infrastructure, security, and SRE teams to define AI-ready integration patterns and ensure scalable production operations.
• Lead technical design reviews and influence architecture decisions across teams building AI-native systems on the platform.
• Define and document reusable patterns, reference implementations, SDKs, and paved paths that accelerate safe AI adoption across ABC Fitness.

WHAT YOU’LL NEED:

• Typically 10+ years of software engineering experience, including deep expertise building distributed backend systems, APIs, orchestration layers, or platform infrastructure; experience in the broader 8–14 year principal range is most aligned for this level.
• Proven experience designing and operating high-scale backend systems with strong understanding of state management, concurrency, reliability, and distributed execution patterns.
• Strong understanding of how LLMs interact with tools and workflows, including schema design, structured outputs, predictable execution patterns, and orchestration reliability.
• Deep expertise in abstraction design and wrapping legacy or complex systems with clean, scalable, and reusable interfaces.
• Experience building workflow orchestration systems handling retries, failure states, long-running processes, and multi-step execution logic.
• Demonstrated ability to define technical standards and influence engineering direction across multiple teams through architecture, design review, and strong engineering judgment.
• Strong production mindset, including experience designing for observability, operational resilience, auditability, scalability, and performance optimization.
• Excellent cross-functional collaboration skills and the ability to work effectively with Engineering, Product, Platform, Infrastructure, Security, and SRE teams.
• A growth mindset and strong learning agility in a rapidly evolving AI and platform engineering landscape.
• A One Team orientation: able to enable other engineering teams, establish scalable paved paths, and create reusable platform capabilities rather than isolated s…