Best alternatives to Rysh CLI in 2026

If you've ever used a program like tmux to split your terminal into multiple panes so you can run several things at once — a code editor in one pane, logs in another, a shell in a third — Rysh CLI does that same job, but with a twist: any of those panes can also become an AI agent that reads your instructions and does the work itself. Instead of typing every command by hand, you can tell one pane to fix a bug while another writes tests, then check back on both later, the way you might glance between several browser tabs. Under the hood, Rysh CLI is written in Go and rebuilds the terminal multiplexer experience — tabs, panes, splits, session persistence — around an actor-based workspace that treats each pane as either a normal shell or an LLM-backed agent powered by Claude or Codex. Agents can resume where they left off after you close and reopen your terminal, and a built-in "agents board" lets multiple agents leave messages for each other to coordinate on shared tasks, with a "fleet" concept for grouping related panes. A feature called SecretNAT swaps real credentials for tokens before any request leaves your machine, so API keys aren't handed directly to the LLM provider. It's open source under Apache-2.0, installable via `go install` or a prebuilt script, and squarely aimed at developers already comfortable with terminal multiplexers who want to add AI agent orchestration on top.