MTS · Vercel, Founder of Stakpak

George Fahmy

Most teams have stopped building agents from scratch. They build on Claude Code or Codex instead, and the interesting work has moved up one level: tools that run many agents, review bots, long running background tasks, factories that turn issues into PRs.To build any of that, you need to program the harness. Start it, stream what it does, steer it, approve its tool calls, resume or fork a session, run it in a sandbox. Each lab ships an SDK for its own harness only. So every tool either commits t