A product spec for computers in Minecraft

01 / What it was

After three days of hands-on fixes, we stopped and wrote a short spec for version 1. The question: what is the smallest thing worth releasing?

The first draft said: persistent terminals and an easy installer, nothing else. The builder then asked for it to be part of our own mod, with blocks from the inventory: a computer block, a terminal block, and a monitor that keeps a web page on it.

02 / How it worked

• Four principles from the spec: place, not thread; local first; bounded; portable.
• It measured what already worked. Sessions survived closing the screen and quitting the game, but not a restart of the bridge service. 'Persistent today means detachable, not durable.'
• The fix it proposed: a tmux server behind every in-game computer, so the shell outlives the bridge and the same session can be opened from a desktop terminal.
• Eight acceptance tests, from 'a variable set before a bridge restart is still there' to 'a clean install with no manual file editing'.
• Named out of scope on purpose: agent bodies, voice, multiplayer, and a 'world in a jar' for subagents.

03 / What we saw

Writing down what did not survive, a restart of the bridge, was the most useful part. It changed the plan from adding features to making sessions durable.

04 / Where it led

The spec was handed to a coding agent to build, and became release candidate 1.1.

Sources

1. Product spec, V1 draft. internal product spec, 16 Sep 2026 So: "persistent" today means *detachable*, not *durable*. V1 closes that gap.
2. Product spec, V1 draft. internal product spec, 16 Sep 2026 Like tmux, but the window is a block in a world.
3. Session transcript. session transcript, 16 Sep 2026 a hermes computer block, and also a termianl block, and i also want, to have a monitor that can display on the monitor webpages
4. Build prompt. build prompt, 16 and 26 Sep 2026 Please build V1 and complete it successfully- dont ask questions, i trust your judgement