Reusing a surface the user already has is the move that unlocks adoption. Same principle behind empla.io, we skip new dashboards and run agents inside the email threads founders already read every morning. Async email interaction actually feels fast at 15 minutes response because the expectation is not real time, which is the same reason tmux works for developers, the pane is already open. The shared-history model is elegant for agent-to-agent collaboration. Did you see conflicts when two agents wrote over each other's history in the same pane, or is ordering deterministic in practice?