ChatGPT (Nov '22), GPT-4 (Mar '23). Copy-paste. Context in your head.
Cursor (Mar '23), Copilot Chat (Jul '23). Single-file edits.
Devin (Mar '24), Claude Code (Feb '25). Real PRs.
MCP (Nov '24). Always-on agents. PRs while you sleep.
cmux, worktrees. 20 branches in parallel.