Head of AI (a16z sr)

Sourcerer builds AI agents that autonomously source and negotiate across B2B marketplaces — navigating platforms via browser automation, conducting multi-turn negotiations, and extracting structured quotes. Our mission is to transform how businesses procure goods by automating complex sourcing workflows end-to-end. Role Overview The Head of AI will own the intelligence layer of our platform and build the team that scales it. This role is strategic and hands-on, focused on designing robust AI systems that operate autonomously in real-world environments. Key Responsibilities AI Orchestration Design and optimize across multiple LLM providers, each serving different roles (conversation, reasoning, media processing) Negotiation Engine Own the AI pipeline driving autonomous supplier conversations, including message generation, conversation assessment, and response routing Prompt Engineering Design structured prompt systems across platforms for negotiation, supplier evaluation, and contact enrichment Platform Expansion Extend AI capabilities to new B2B marketplaces and messaging channels Reliability & Evaluation Build testing frameworks and evaluation practices for non-deterministic AI outputs Team Leadership Hire, mentor, and manage a high-performing engineering team as the company scales Minimum Qualifications 4+ years in software engineering, with 2+ years building production LLM applications (autonomous systems, not prototypes) Hands-on experience with multiple LLM APIs (structured outputs, tool use, cost optimization) Strong Python skills, including FastAPI, async programming, and Pydantic Experience with browser automation (Playwright or Puppeteer) at scale Background in early-stage startups or high-ownership environments Proven experience hiring and managing engineers Strong communication skills with the ability to translate AI capabilities into product decisions