Minecraft AI bot plan hits 月数円 with Jev, Gemini, Mineflayer

The design reflects a common split among hobbyist AI projects: one layer handles the instruction and conversation flow, another picks among allowed moves, and a third keeps a long-lived game connection. Here that means Jev formats the user's natural-language request together with the bot's role, current situation, and available actions; Gemini then selects one action and returns it as structured JSON rather than prose; Mineflayer executes the approved action.

The author is explicit that this is a design example rather than a working product. The repository includes no bot implementation or Jev API definitions, so buildPrompt and similar code must be adapted to Jev's actual interface. Safety choices are central: inputs are length- and character-limited, untrusted chat is not treated as commands, and the bot side re-validates whatever reaches it before calling the Mineflayer API. Failures such as network errors, empty responses, or broken JSON result in no action at all.

On cost, the few-yen-a-month figure is described as a target that only holds when an existing machine runs the bot and each service stays within its free tier. Renting new hardware can push the bill past that on its own, and the author notes that Gemini and Cloudflare free tiers, pricing, and available models change, so conditions should be checked before launch. Whether the cheap-operation claim holds for a given reader therefore hinges on usage volume, uptime, and which machine is already on hand.