Principal Harness Engineer (AI)

Location: Work from Home, United Kingdom

Company

hirify.global is a global analytics software company that helps businesses in more than 100 countries make better decisions through analytics, artificial intelligence, machine learning, and optimization.

What you will do

• Design, build, deploy, and support the guides, feedback loops, guardrails, and shared context that form the harness for AI coding agents.
• Develop agent instruction files, reusable skills, architectural rules, reference documentation, and codemods, driving engineering standards across teams.
• Build custom linters, static analysis, architecture-fitness tests, verification loops, and LLM-based review systems to identify issues before human review.
• Define quality gates, release criteria, agent authority boundaries, and escalation rules for agent-produced work.
• Establish LLM testing and evaluation infrastructure, apply consumer and contract testing, and improve observability of agent-assisted development.
• Partner with product and platform teams, convert specifications into enforceable controls, and mentor engineers in harness practices and responsible AI tool usage.

Requirements

• Bachelor's or Master's degree in Computer Science or a related discipline, or relevant commercial experience.
• Strong experience in software architecture, design, development, and testing across large, complex codebases.
• Hands-on experience with AI coding agents such as Claude Code, Codex, or similar tools.
• Experience building engineering tooling with linters, static analysis, CI/CD pipelines, containerized build and test environments, and observability.
• Knowledge of spec-driven development, context engineering, agent orchestration, fitness functions, and developer-platform work.
• Working knowledge of autonomous-agent security, including prompt injection, permission scoping, sandboxed execution, audit trails, and least-privilege guardrails; excellent communication skills are required.

Nice to have

• Experience with consumer or contract testing approaches such as Pact.
• Familiarity with agent instruction conventions such as AGENTS.md.

Culture & Benefits

• Inclusive culture based on ownership, customer focus, and respect.
• Professional development through learning experiences and opportunities to use individual strengths.
• Competitive compensation, benefits, and rewards programs.
• People-first environment supporting work-life balance, employee resource groups, and social events.