Zac Hatfield-Dodds is a member of technical staff at Anthropic, an AI safety and research company in San Francisco. He works on building reliable, interpretable, and steerable AI systems. Previously, he contributed to the Autonomy, Agency, and Assurance Institute. Zac also volunteers for community organisations and served on the board of the ACT Conflict Resolution Service and the executive of Effective Altruism ANU. He organises events like the mentored sprints and co-authored a report on PEPFAR. A PSF Fellow, Zac regularly contributes to open source software and is the lead developer of Hypothesis. He also co-maintains Pytest and started hypofuzz.com. Zac often speaks at conferences.