Mirrai Careers
Resume BuilderCareer Test
InsightsPricing
Get Started Free
Jobs/Senior Member of Technical Staff, Harness Engineering

Senior Member of Technical Staff, Harness Engineering

harperinsure

San Francisco Full-time$185k–$350k / year Posted 3w ago
Above market. This role pays above the $188k median for similar USD roles (84 comparable postings in our corpus).
Apply on company site
SENIOR MEMBER OF TECHNICAL STAFF, HARNESS ENGINEERING Harper is an AI-native commercial insurance company in San Francisco. We're not bolting AI onto insurance — we're rebuilding the entire business as software, on a simple bet: turning expert human judgment into compute is one of the largest transitions left to make, and a trillion-dollar industry still run 90% by hand is the place to prove it. We've grown ~100x in the last year and we move at that speed — on-site, in person, long days, very high standards. Almost no one joins Harper for insurance; they join to build the company that replaces how it works. THE ROLE The model is only one part of a worker. The loop, the tools, the memory, the execution environment, the guardrails, the fallback path, the observability — that's what decides whether an agent can actually do useful work inside a real company. That's the harness, and at Harper every agent (product and coding) rides on a shared one. If the harness is brittle, every pod ships brittle agents; if it's good, pod engineers stop rebuilding the same scaffolding and start shipping agents in days instead of weeks. That makes the harness the company-specific leverage behind the whole bet — the model is replaceable, the substrate beneath it is the moat. You'll build inside the harness layer — the meta-harness wrapping our frontier coding agents, OpenClaw, Hermes, and our internal agents — working alongside the engineer setting harness direction, shipping the primitives every agent team depends on. WHAT YOU'LL DO * Build agent-loop primitives. Prompt construction, tool routing, retry/timeout/budget logic, multi-step orchestration. * Ship execution-environment infra. Sandbox lifecycle, isolation, blast-radius limits, filesystem and network policy for agents. * Own the tool layer for your domains. Schema, auth, rate-limit, observability per tool — tools other engineers build on. * Wire model-provider routing. Provider fallback chains, eval-driven model selection, cost/latency tradeoffs. * Ship harness SDK improvements — whatever makes pod engineers faster. * Eat your own dog food. You write code with our harness daily and feel every rough edge before anyone else reports it. WHAT WE'RE LOOKING FOR * 3–6 years building software, with production agentic systems behind you (real users, real traffic — not demos) and experience with at least one major agent framework. * You think in tool design, not just prompt design, and can describe a tool-design or sandbox decision you'd still defend in three years. * Production agent/LLM systems experience: agent loops, tool integration, prompt engineering at scale. * You write code with AI daily and manage 3+ parallel sessions. * Strong written communication (API contracts, integration guides, internal docs). * Bonus: sandbox/isolation infrastructure; open-source agent-framework contributions; foundation-model partner or early-access experience. THE REALITY On-site in San Francisco, in person, long days, high standards. The harness is infrastructure other engineers build their work on, so the bar is high and the blast radius is real — when you get it right, the whole org's agent velocity moves; when you don't, everyone feels it. The right person wants that leverage and that pace. LOGISTICS * Compensation (OTE): $187,000–$264,000 cash (base + target performance bonus), plus competitive equity. * Location: San Francisco, in-office. Based here or willing to relocate. * Benefits: Uber commuter benefits; breakfast, lunch, and dinner provided; snacks and coffee stocked; free gym membership; health, dental, and vision. * Process: Founder call (15 min) → Tech Lead deep-dive (60 min, harness) → Super Day on-site → founder + Tech Lead offer. No committee. Best offer, first. To apply: If you've shipped an agent loop or a tool layer that real engineers depend on — send your resume, the code, and tell us about a harness decision you'd defend.

See how well you match this job

Upload your resume and we’ll score your fit for this role and 6 similar roles — then tailor your CV to it with AI. Free, no credit card.

Check your match

Similar jobs

  • Staff Engineer, Harness Engineering

    harperinsure

    San Francisco$200k–$350k
  • Senior Member of Technical Staff, Developer Experience

    harperinsure

    San Francisco$176k–$253k
  • Senior AI Engineer - Agent Team

    furtherai

    San Francisco$225k–$325k
  • Staff Engineer, Agentic Intelligence - San Francisco

    homevision

    Remote
  • Staff Engineer, Agentic Productivity and Infrastructure - San Francisco

    homevision

    Remote
  • Software Engineer, Codex Core Agents

    OpenAI

    San Francisco$230k–$385k
Apply on company site

Want more roles like this? Browse fresh jobs or tailor your resume with AI.

Mirrai Careers

AI-powered career platform: build resumes, match jobs, and plan your career.

Product

  • All Tools
  • Resume Builder
  • Career Test
  • Pricing

Legal

  • Privacy Policy
  • Terms of Service
  • Fair Use Policy

Company

MIRRAI CHAT LTD (Company No. 16403306)

71-75 Shelton Street, Covent Garden

London, WC2H 9JQ, UNITED KINGDOM

[email protected]

© 2026 Mirrai Careers. All rights reserved.