Fabric is an open-source framework for augmenting humans using AI, centered on a large library of crowdsourced prompt templates called 'patterns'. The system provides a CLI tool, a REST API server, and a SvelteKit web UI, all sharing a common pattern engine that applies structured prompts to user input (text, URLs, YouTube videos, PDFs, images). The architecture is modular: a plugin registry manages AI vendor adapters (OpenAI, Anthropic, Gemini, Ollama, Azure, Bedrock, Vertex AI, and 25+ OpenAI-compatible providers), a template engine supports variable substitution and executable extensions, and a filesystem-backed storage layer handles patterns, sessions, and contexts with path-traversal protection. Key entry points include the Go CLI (`cmd/fabric`), the Gin-based REST API (`internal/server`), and the SvelteKit web app (`web/`). External dependencies span multiple AI SDKs, web scraping libraries (go-readability), YouTube transcription (yt-dlp), and SQLite for caching. The pattern library itself is a data asset with over 100 markdown files, each defining identity, steps, and output instructions for tasks like summarization, analysis, code review, and creative writing.