August 24, 2026 · Joy · What JoyMux guarantees · Part 1

What JoyMux actually guarantees

Most coding tools focus on the agent. JoyMux focuses on execution state underneath — what happened on your machine, and what still exists after the chat window is gone.

The shift is simple:

• Without: Conversation → commands → conversation remembers
• With: Agent → JoyMux → machine → durable execution state

Your AI shouldn’t have to remember your computer. JoyMux is that memory — local, persistent, shared across harnesses.

This note is the public contract. It is not a blueprint for rebuilding JoyMux.

The five guarantees

1. Interrupt — The terminal can disappear. The execution record doesn’t. Execution state survives interruption and can be recovered without reconstructing the task from chat history.
2. Resume — Continue from durable execution state instead of reconstructing from conversation.
3. Hand off — Change coding agents without throwing away the execution state they need. Codex, Claude Code, Gemini, and OpenCode can attach to the same local record.
4. Shrink context — Keep the complete execution record locally while giving the next agent only the relevant change.
5. Verify — Execution evidence remains available independently of the model’s memory. Replay what actually ran.

JoyMux does not plan missions, pick coding-agent models, or replace your harness. A zero exit code means only that the process exited normally.

What this is not

Not another chat. Not another IDE. Not an orchestrator. Not a sandbox. Not a public remote-control plane.

After a daemon restart, resume is from durable evidence. Reattaching a live terminal is not always claimed. That limitation is part of the contract.

Don’t trust this page

Test the invariant:

1. Start work through JoyMux.
2. Interrupt or close the client.
3. Return.
4. Verify the execution record remains available.
5. Hand the work to another supported agent.
6. Measure how much rediscovery is required.

If the record is gone when the terminal dies, the product failed. If the next agent has to reconstruct the machine from conversation, the handoff failed.

How to read this series

1. What JoyMux actually guarantees — this page
2. Sessions that survive a closed terminal
3. What JoyMux keeps (and what the agent sees)
4. Trial, the lease file, and $29/month

Want the operator contract, not the story? Start in docs — what JoyMux guarantees.