For decades, software engineering followed the same loop: pick up a ticket, enter flow state, write code, open a PR, wait for review, merge. The work was sequential because the bottleneck was always a human writing code. AI coding agents broke that assumption. By early 2026, every Coinbase engineer had access to Cursor, Copilot, OpenCode, and Claude Code (we wrote about that adoption journey in "Tools for Developer Productivity at Coinbase" last August). Agents were fast.