Make sure a one-of-a-kind artifact exists exactly once in the world

A legendary sword is handed out by the quest, found in a chest and sold by a trader, and suddenly two of them exist, or none because its owner fell into a pit. Here is a ledger that always knows who holds it and brings it home when the holder is gone.

Why this works

A thing that exists once needs one place that says where it is. If every move goes through the same few doors and each door checks the book first, no path can make a second copy or take it from someone who never had it.

When not to use it

Skip it for ordinary items, and for a game where several players each get their own copy of the same legendary item. Counting every copy costs care and gains nothing there; use plain stacks and a per-player flag.

In the full entry

• What to build, step by step
• Starting values and the reason for each
• 4 common mistakes and the fix
• A diagram of every state
• 24 lines of example code with 3 checks that pass
• How your AI shows you that it works

Say this to your AI

Use the Spielerando entry "Make sure a one-of-a-kind artifact exists exactly once in the world" (read_entry one-of-a-kind-artifact-ledger) in my game. Build it step by step, and show me how you checked that it works.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP