I built speedmux to make parallel agent workflows manageable from one terminal interface.

At a high level, the architecture is:

1. one terminal multiplexer process managing multiple concurrent sessions 2. per-session isolation so each agent/task can run independently 3. a persistent sidebar that tracks session state/activity without switching context 4. rendering/performance path powered by libghostty, which keeps interaction latency low even with multiple active sessions

It’s written in Go, and a lot of it was vibe-coded with Codex.