Systems Engineer — Model-Based & Formal Methods

Sigil Logic builds AI for rigorous engineering. Our platform, HOARDE, is a multi-agent system that brings formal methods and model-based engineering into the workflows teams already use. It connects requirements, architecture, software, firmware, hardware, tests, and proofs; orchestrates the right verification tools for each problem; and produces an auditable record of why a system works.

We are building for teams whose systems must not fail. Our mission is to make high-assurance engineering practical and scalable: to turn decades of research and experience on nationally critical systems into an everyday engineering capability.

We believe formal methods are among the most powerful ways to make AI-generated systems trustworthy. We are working at the frontier where LLMs, automated reasoning, and real hardware and software meet—and we believe that combination will reshape how engineering is done.

We are expanding HOARDE's systems-engineering capabilities. We need an engineer who can turn mission and operational intent into precise requirements, architectures, interfaces, and behavioral models—and carry that intent forward until teams know what to build and what evidence must show that it works.

This role owns the upper part of the engineering refinement chain: concepts of operation, domain models, requirements, architecture, behavior, interfaces, constraints, and analysis. You will make those artifacts machine-readable, internally consistent, connected to implementation and verification, and useful throughout the life of a system.

A substantial part of the job is product development: turning systems-engineering methods into reliable HOARDE agents, model transformations, analysis workflows, and traceability infrastructure. The rest applies those capabilities to real cyber-physical and software-intensive systems, including avionics, autonomous and embedded systems, critical infrastructure, processors, and accelerators. Project work exposes the gaps; the product turns each solution into a repeatable capability.

• Extend HOARDE's systems-engineering capabilities through reliable agents, model transformations, analyses, workflows, and engineering evidence.
• Refine mission objectives, concepts of operation, stakeholder needs, domain knowledge, and constraints into engineering artifacts.
• Develop requirements, architecture, interface, behavioral, and product-line models that define system, trust, and proof boundaries; responsibilities; interactions; assumptions; guarantees; resources; and failure behavior.
• Analyze models for completeness, consistency, compatibility, feasibility, safety, security, timing, resource use, and other properties.
• Translate system intent into allocations, contracts, invariants, tests, and proof obligations for software, firmware, hardware, and verification teams.
• Maintain traceability across intent, requirements, architecture, design, implementation, tests, analyses, and assurance evidence as the system changes.
• Explore architectural alternatives, product variants, and trade spaces, making their constraints and consequences legible to decision-makers.
• Work with domain experts, customers, and implementation teams to resolve ambiguity, reconcile models with reality, and turn successful work into reusable HOARDE capabilities.

• Hands-on experience in systems engineering, model-based systems engineering, cyber-physical systems, or complex software-intensive architecture.
• Experience using formal or semiformal models for engineering decisions—not only documentation. You can state meaningful system properties and investigate them through automated analysis or formal reasoning.
• A strong understanding of how intent, requirements, architecture, interfaces, behavior, implementation, verification, and validation constrain one another.
• A record of delivering models, architectures, requirements, analyses, or assurance artifacts that materially influenced a real system—and a product mindset about making that work reusable.
• Enough Kotlin/JVM experience to contribute to HOARDE's agents, model integrations, and analysis workflows.
• The ability to move between abstraction levels, expose hidden assumptions, and communicate with domain experts, program leaders, implementation engineers, and formal-methods specialists.
• Sound judgment, precise communication, self-direction in a small distributed team, and curiosity about making AI-generated requirements, models, and designs trustworthy.

This role touches many tools and domains. Depth in any subset can be valuable.

• Architecture and requirements: AADL and OSATE, SysML or SysML v2, Syside, Lando, FRET, controlled natural language, or system-as-code workflows
• Behavior and composition: State machines, CSP, TLA+, Alloy, PVS, Simulink/Stateflow, FMI/FMU, contract-based design, or heterogeneous model composition
• Cyber-physical analysis: Scheduling, timing, resource budgets, mixed criticality, fault, hazard, and threat analysis, safety/security co-engineering, resilience, or control-system modeling
• Product lines and trade spaces: Feature models, Clafer, variability, architecture generation, multi-objective analysis, or reasoning across system families
• Assurance and certification: Assurance cases, GSN, evidence planning, requirements-based verification, tool qualification, certification objectives, or regulated safety- and security-critical engineering
• Tool and workflow integration: Model transformation, validation, generation, repositories, machine interfaces, CI for models, visualization, or connections to implementation, tests, and proofs

If the work sounds like you and you bring strong systems-engineering foundations, experience using models to reason about real systems, and the ability to learn, we want to hear from you.

Sigil Logic is a small, early team. You will work directly with people who have spent their careers building high-assurance systems, and you will have real influence over our product, methodology, and engineering culture. We value intellectual range, precise communication, practical output, and colleagues who teach what they know while learning from others.

We are headquartered in Portland, Oregon, and work as a fully distributed organization. Being in Portland is welcome, but we will not let geography keep us from the right person.

Email join@sigillogic.com with your resume or CV and a short note about the systems-engineering, modeling, or formal-methods work you are proudest of. Links to models, code, papers, talks, or project artifacts are welcome but not required.

Learn more about Sigil Logic and HOARDE.