Open Dungeon is a fully local AI roleplay application that generates both narrative text and inline scene images on-device. Built as a Next.js 16 application with a React 19 frontend, it provides a rich interactive fiction experience where users can write actions, dialogue, or narration, and the AI narrator responds with streaming prose. The system supports multiple text backends: local Ollama models (Gemma 4 QAT variants) or any OpenAI-compatible server (LM Studio, llama.cpp, OpenRouter, etc.). Image generation is handled by a separate Python HTTP server that wraps optimized FLUX.2-klein backends (MFLUX/MLX on Apple Silicon, PyTorch SDNQ on CUDA/CPU) or an existing ComfyUI instance. The architecture is a monolith with a Next.js server handling API routes, SQLite for persistence, and an optional sidecar image server. Key entry points include the main chat UI (src/app/page.tsx), the story API (src/app/api/story/route.ts) which handles streaming narration, and the image generation API (src/app/api/images/route.ts). The codebase demonstrates strong engineering practices: thorough streaming support with artifact filtering, robust error handling with timeouts and fallbacks, clean database abstraction, and well-structured Python image server with resident model support.