Harness Engineer

Virio•San Francisco, CA

21h•$375,000 - $625,000•Onsite

About The Position

Virio is building the next-generation B2B GTM stack. Backed by investors and operators from LinkedIn, YouTube, HubSpot, Rippling, and Google, we help the fastest-growing B2B companies go to market through executive-led content that drives revenue. We’re growing extremely quickly, added $1M ARR in 30 days, and are onboarding customers faster than we can manage—so we’re looking for a Growth Engineer to build internal tools and workflows to augment our team.

Requirements

High agency & self-direction – Acts without waiting for requirements or detailed instructions
Small-team intensity comfort – Comfortable working intensely and closely with a small, high-output team
Unorthodox problem solving – Sees non-obvious paths forward and challenges conventional approaches
Quality-driven execution – Detail-oriented with high standards for correctness and quality
Low ego & accountability – Takes full ownership and accountability for outcomes

Nice To Haves

Background in English, literature, creative writing, or humanities

Responsibilities

Build and refine the system prompts, tool integrations, and context windows that shape how our models behave across our platform—you'll see how small prompt tweaks cascade into measurable product impact.
Design the evaluation framework (LLM-as-judge evals, deterministic tests, production monitoring) that lets us ship with confidence. You'll define what success looks like and build the metrics to measure it.
Architect the abstraction layer between our product (file systems, artifacts, skills) and the model's capabilities—making complex multi-step workflows feel natural to the model and reliable to users.
Own prompt versioning, experimentation, and iteration. You'll A/B test prompt variations, measure their impact on agent quality, and ship improvements across our production system.
Collaborate with product and engineering to identify signal—where our agents are failing, where users are stuck—and translate that into prompt and architecture improvements.

Benefits

Competitive total compensation aligned to impact and ownership
Meaningful equity upside as part of the founding team
Medical, dental, and vision insurance
401(k) plan
All working meals covered
Relocation support for San Francisco
Company-wide annual off-site
Direct access to founders and leadership
High ownership, high trust, and fast career progression alongside world-class client partners
In-person culture with deep commitment to excellence