The Changing Craft of Programming with John Crepezzi

Jane Street's AI coding agents now originate ~45% of released pull requests, but verifying their work has become the harder bottleneck.

• Jane Street's AI origin story: ChatGPT launched during John Crepezzi's first week on the job in December 2022; within three days a prototype became "JaneGPT," a firmwide chat app using API access to avoid training-data exposure.
• Agentic coding is now firmwide infrastructure: an internal CLI tool called "aid CLI" (similar to Claude Code) plus a Slack-driven system called AIDMINT now auto-creates roughly 45% of released pull requests ("features") at the firm.

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