Prompt Poet is a low-code prompt design library that streamlines prompt creation for developers and non-technical users. It combines YAML for structured prompt definitions with Jinja2 for dynamic variable rendering and control flow. The library processes templates in two stages: first rendering Jinja2 variables and logic, then parsing the output as structured YAML messages. It integrates with LangChain to pass rendered prompts directly to chat models like GPT-4o-mini.