Blog
What JoyMux guarantees
Crash? Resume. Missed output? Replay it. Send the delta — not the whole terminal history. This page is updated as the product ships. Internals stay unpublished.
What JoyMux guarantees
Start here if you want the contract — guarantees, evidence, how to verify — not an internals dump.
Part 1
What JoyMux actually guarantees
Your AI shouldn't have to remember your computer. The public contract — interrupt, resume, hand off, shrink context, verify — and how you test it.
Part 2
Sessions that survive a closed terminal
Detach does not kill the work. Attach reconnects you. Close ends the session. User-visible lifecycle — not an internals dump.
Part 3
What JoyMux keeps (and what the agent sees)
Keep the complete execution record locally. Send the model only the delta. Replay is reading the record — not reconstructing it from chat.
Part 4
Trial, the lease file, and $29/month
14 days free, $0 due today. A signed lease on your machine. Then $29/month through hosted checkout — card details never touch joymux.com.
Field notes
August 27, 2026
Why JoyMux is different
Research on existing products — tmux, native CLI resume, cloud sandboxes — and why chat history is still a bad database for your computer.
August 24, 2026
Training my own AI while coding agents run
A founder use case — GPU training jobs plus multi-agent coding on the same box. JoyMux kept execution state durable and context bounded so the machine stayed usable.
August 23, 2026
Handoff rediscovery — the measured claim
The unfinished checkout API Agent A handed off. On that snapshot, rediscovery calls went 15 → 1, files reread 8 → 0, context tokens 2409 → 271. Tests still passed. Not a speed claim.
August 22, 2026
One execution layer for Codex, Claude Code, Gemini, and OpenCode
Your harness will change. Execution state should not. Codex, Claude Code, Gemini, and OpenCode over the same local execution record.
August 22, 2026
Missed the output? Replay it from exact evidence
Scrollback is not a record. Replay from durable execution evidence when you were looking at the other pane.
August 22, 2026
Send the delta, not the whole terminal history
Dumping full scrollback into the next prompt wastes tokens and blurs the work. Bounded context views send what changed.
August 22, 2026
Your agent shouldn’t forget everything because a terminal died
Terminals are disposable. Execution shouldn’t be. How persistent sessions let coding agents resume after a crash.
August 22, 2026
Disposable terminals are a bad runtime for AI coding agents
A terminal is a window, not a runtime. Why multi-agent work thrashes the machine when execution lives in tabs.
August 6, 2026
Hard reset, same state
A crash should not mean starting over — or paying the tokens again. Recover to the same execution state.
August 5, 2026
About 10× — saying the token number honestly
Token savings are a consequence of persistent execution and bounded context — not the headline. Founder testing saw about 10×, with clear metering labels.
August 1, 2026
Why JoyMux exists
Most tools focus on the agent. Almost nobody focuses on execution state underneath — what survives when the terminal dies.