Viper LLM

Viper LLM is a server-side Fabric mod that links Minecraft chat to providers including OpenAI, Anthropic, Gemini, Ollama, OpenRouter and LM Studio. Each provider is reached through its own API. An OpenAI-compatible endpoint is also supported, with automatic endpoint detection. API keys are stored in plaintext on the server, in per-player profiles under world/viperllm/players/. Fabric API is required, and the mod is published for Fabric only, across 17 release versions, 1.21 – 26.3.

The assistant can read live game data through a built-in tool system that covers stock, crafting patterns, coordinates, forecasts, storage blocks, text on signs, written books and more. Tool calls never appear in chat; players see only the final answer. When a small local model writes malformed tool markup, a DSML-style example for instance, the mod repairs the call and retries automatically if it still cannot be parsed. Vanilla clients join a ViperLLM server and use the feature immediately, and the mod works on dedicated servers, singleplayer and integrated servers.

Each command is executed with the permissions of the player who issued it, and the mod never raises those permissions. A global per-player switch controls whether a player's assistant is active. Protecting the world directory is suggested before backups.