John Schulman developed the Tinker API concept across OpenAI and Anthropic
Sherwin Wu · DevDay 2025: Apps SDK, Agent Kit, MCP, Codex and why Prompting is More Important than Ever · Oct 7, 2025 · at 22:35
Sherwin Wu (OpenAI API lead) discusses the background of former OpenAI co-founder John Schulman's project, the Tinker fine-tuning API, across his time at OpenAI and Anthropic.
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“Right when I joined OpenAI, like, this has actually been, I think, a passion project of John's. Like, he's been talking about doing something in this, like, in this shape for a while, which is, like, a truly, like, low-level research, like, fine-tuning library. And so we actually talked about it quite a bit when he was at OpenAI as well. It's actually funny. I talked to one of my friends who said that when he was at Anthropic, he also, you know, worked on the idea for a bit.”
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