Applied AI Engineer, Core Platform

About the Role Lumbra is building Nebula, an agentic harness that makes AI agents reliable, evaluable, and useful for real analytical work in high-consequence environments. We’re looking for an Applied AI Engineer to own the intelligence layer of the harness: how agents reason, call tools, retrieve knowledge, and produce trustworthy outputs. You’ll build production systems and research prototypes in equal measure, working at the boundary of what’s possible with artificial intelligence today. What You’ll Own Design and evolve our provider-agnostic LLM integration layer , maintaining a unified abstraction over streaming, tool calling, structured output, and context management that lets the platform run multi-turn, multi-agent conversations across models with no configuration changes. Develop advanced agent orchestration techniques that combine deterministic and non-deterministic tool use to produce complex, multi-step action chains. Outputs must be traceable, interpretable, and grounded in robust, verifiable citations. Build MCP servers over internal data sources and systems, designing agent-native interfaces that go beyond API wrappers to reduce ambiguity, improve determinism, and give agents first-class access to organizational knowledge. Extend our MCP-based tool interaction framework with capabilities like structured citations, multimodal tool output, and rich provenance metadata that let agents reason transparently about the results they consume. Architect the agentic memory layer for short-, medium-, and long-term recall across tasks and projects, spanning vector, text, graph, and filesystem stores. Design retrieval strategies that efficiently surface the right context to agents at scale. Preferred Qualifications Experience building production agentic systems , including the infrastructure for reliability, observability, and evaluation, not just prompt engineering. Background in evaluation methodology for AI systems: offline benchmarks, human-in-the-loop review, inter-annotator agreement, or similar quality measurement frameworks. Familiarity with prompt engineering at scale : template management, few-shot optimization, chain-of-thought patterns, and systematic prompt testing. Prior work with the Model Context Protocol (MCP) or similar tool-use standards for agent-to-system interaction. Experience with information retrieval systems : search ranking, relevance scoring, or hybrid keyword and semantic search. Understanding of AI safety practices : output filtering, hallucination detection, constrained generation, or grounding techniques. Prior work in analytical domains (intelligence, investigations, due diligence, research, competitive intelligence, or similar) that informs what “useful AI” means for practitioners making high-stakes decisions. Benefits Comprehensive medical, dental, and vision plans Premiums 100% covered by Lumbra for all employees Exceptionally low premiums for spouses and dependents Basic life insurance and disability 100% covered for all employees by Lumbra Option to purchase additional life insurance available Take the time off that you need, when you need it’ paid time off, not accrual based Generous company holiday calendar including a holiday shutdown in December Supportive leave of absence program including time off for military service, medical events, and parental leave Full 401(k) retirement plan for all full-time eligible employees Company-funded commuter benefits Free access to on-site gym at office #J-18808-Ljbffr