About the Role Join an early-stage consumer AI company as its founding product engineer, with ownership of an AI assistant and its end-to-end user experience. You will work across agent behavior, product interfaces, and evaluation systems to help make everyday tasks easier for users. What You'll Do • Build the agent decision-making layer, including tool-calling loops, memory, context assembly, prompt design, and model routing. • Create evaluation infrastructure with conversation replay, turn-level assessments, and regression suites to guide release decisions. • Own product experiences across mobile and web, from onboarding and initial interactions to ongoing use, group conversations, approvals, and trusted networks. • Ship features end to end, using experimentation and feature flags to measure outcomes and improve the product. • Develop integrations with email, calendars, bookings, payments, and browser automation, including reliable tool-use and user-approval flows. • Review conversations, speak with users regularly, and use feedback and product data to prioritize improvements. • Set engineering standards and help grow the team while remaining hands-on. What We're Looking For • At least 4 years of software engineering experience at an AI product company, AI lab, or consumer product company shipping products at scale. • Production experience building agents with tool use, memory, and long-running conversations, along with evaluation systems that inform shipping decisions. • Full-stack experience with TypeScript, React, Next.js, and Postgres. • Experience with third-party APIs, OAuth, payments, or agent tools such as function calling, MCP servers, and browser automation. • A record of owning features end to end and demonstrating measurable product impact. • Strong product judgment, consumer experience sensibility, and fluency with AI-assisted development, including verifying and owning shipped work. • Experience leading a growing engineering team while staying hands-on, and evidence of sustained contribution at an employer or deep technical expertise. • 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.