AI startup Deeptune has raised a $43 million Series A to build what it calls “training gyms” for AI agents, Fortune has learned exclusively. Andreessen Horowitz led the round, joined by 776, Abstract Ventures, and Inspired Capital, with angels including OpenAI researcher Noam Brown, Mercor CEO Brendan Foody, and Applied Compute CEO Yash Patil.​ Deeptune creates high‑fidelity reinforcement learning (RL) environments that simulate the day‑to‑day workflows of roles like accountants, customer suppor...