Share a world, and join one

Sharing

Open a single-player world, press Escape, and press Open to Nodera…. It sits where vanilla's Open to LAN button sits, because it replaces it: this is how you play with other people here, not a second way bolted on beside the normal one.

That opens a screen with three settings, and nothing is announced until you confirm it:

Nothing about your save changes. The world you were playing is the world that is now shared — no import, no conversion, no copy. From then on the screen reads Nodera: Sharing options… and offers Update sharing options and Stop sharing.

What "shared" publishes

Three facts: that the world exists, what its identity is, and that your node is currently holding it. It does not publish your save for anyone to download — content is encrypted per world, so a peer holding pieces of a world it is not a member of holds bytes it cannot read. It does not publish your address either; when there is no direct path, reachability goes through a relay, which is a circuit between two peers rather than a listing.

Joining

On the other machine, open Minecraft's multiplayer screen. NoderaMC replaces it entirely, with two tabs:

• Worlds — worlds your own node is already involved with, plus everything the trackers you have configured will tell you about. Search, Refresh, Join world and View pieces are here.
• Network — a Trackers panel and a Rendezvous panel: which of your configured services are answering, how long ago, and how many worlds each is indexing.

/nodera worlds prints the same Worlds list in chat.

What pressing Join actually does

1. If the row already carries a live game endpoint, the client connects straight to it.
2. Otherwise it asks the tracker for the world's current endpoint claim.
3. If there is no claim, the host's game is closed — so this machine fetches the world from the peer network through its own worker and re-opens it locally. You become its host. This is the same mechanism that keeps a world alive when its host leaves, arriving from the other direction.
4. Only if that also fails do you get an error, and the error says which step failed. "The host's game is closed — the world is archived on the network but not currently playable" is a different problem from "this world has no network identity yet", and both are different from a password prompt.

What the badge on a world means

The badge is about copies of the world, not about validators. A world running with fewer validators than its committees want is a separate report — the in-game diagnostics call that degraded, and the fix is the same either way: another peer coming online.

Your library

The companion app's Library screen groups worlds three ways.

You are playing in — where a player on this machine is right now.

Worlds you run — worlds whose identity you hold. You created them, or ownership was transferred to you, and your key is what signs administrative changes to them.

Worlds you help share — worlds you have played in. Your node holds pieces of them and validates regions for them, and it keeps doing that with Minecraft closed. This is the group that makes the network work, and you join it by playing rather than by opting in.

A world stays in the last group because your node keeps telling the world's other peers that it is still here. Stop — the machine is off, the app has been closed for a week — and the membership expires. That is correct behaviour: it keeps a world's committee made of machines that exist rather than of every machine that ever visited, and it is why "how many peers does this world have" is a number that moves.

Administering a world

Authority is a key, not a username. Every one of these is signed by the world's author key and re-verified by whoever receives it, so "the server said so" is never enough.

If something looks wrong

/nodera selftest runs the client's own diagnostic pass and prints what it found. It is the first thing to run before reporting anything, and far more useful in a bug report than a description of what the screen looked like.