Founding Product Engineer

About the Role Join an early-stage consumer AI startup as its founding product engineer, with ownership of the AI agent and the user experience from end to end. You will work across product engineering, agent behavior, and evaluation, helping shape a personal assistant that can take useful actions while earning user trust. What You'll Do Build the agent's decision-making system, including tool-calling loops, memory, context assembly, prompt design, and model routing. Create evaluation tools such as turn-level judges, conversation replay, and regression suites to assess response quality before releases. Own the mobile and web product experience, including onboarding, follow-ups, group conversations, approvals, and trusted connections. Ship features from concept through experimentation and release, using user feedback and product data to guide decisions. Build integrations with email, calendars, booking services, payments, and browser automation, with reliable recovery and user approval flows. Review conversation transcripts, speak with users regularly, and help set engineering standards and grow the team. What We're Looking For At least 4 years of software engineering experience, including work on AI products, AI systems, or consumer products used at scale. Production experience building agents with tool use, persistent conversations, and memory, plus evaluation systems that support release decisions. Full-stack skills with TypeScript, React, Next.js, and Postgres. Experience with third-party APIs, OAuth, payments, or agent tools such as function calling, MCP servers, or browser automation. A record of owning features end to end and delivering measurable product outcomes, with strong product and design judgment. Comfort using AI-assisted development tools while verifying and taking responsibility for shipped code. Post-training or fine-tuning experience is a plus. Compensation & Benefits Base salary: $200,000 to $300,000 annually. Visa sponsorship is not available. Location On-site in San Francisco, California. Full-time role.