DEV Tutorial Shows How to Build LLM Narrative Contracts Using .meph Format

A developer tutorial on DEV Community introduces .meph, a custom contract format designed to structure LLM-driven storytelling with defined rules and constraints. The guide walks readers through setting up the open-source Mephisto engine, which requires Go 1.26+ and optionally an API key from providers like OpenAI, DeepSeek, or Ollama. Users create a contract file that defines a character's name, core personality anchors, dynamic state variables, worldview, background, and opening scene using a structured but markup-light syntax. The engine automatically infers data types from state values, enabling conditional logic without manual conversion. The tutorial uses Faust as a sample character to demonstrate how written rules directly shape AI-generated narrative output.