Anthropic Skills is the official open-source framework for creating, sharing, and deploying Agent Skills for Claude. Skills are specialized instruction sets -- folders containing instructions, scripts, and resources -- that Claude loads dynamically to complete specific tasks in a repeatable way. The repository has amassed 74,900 GitHub stars and 7,700 forks since its September 2025 launch, making it one of the fastest-growing developer tools in the AI agent ecosystem. The framework covers a wide range of skill categories including creative and design applications, development and technical workflows, enterprise communication, and document manipulation. Skills can be used across Claude Code, Claude.ai, and the Claude API, providing a unified extensibility layer for Claude-based workflows. ## Skill Architecture and Template System Every skill follows a standardized template structure with YAML frontmatter containing a unique name identifier and a description field. The body contains markdown-formatted instructions that Claude follows when the skill is activated. This consistent format means any developer can author a new skill without learning a custom DSL or framework -- plain markdown and optional Python scripts are all that is required. ## Document Skills for Office Automation The repository includes production-grade document skills for creating and editing DOCX, PDF, PPTX, and XLSX files. These source-available reference implementations demonstrate how to build complex, multi-step skills that coordinate file I/O, formatting logic, and content generation. While shared for educational purposes, they represent the level of sophistication achievable with the skills framework. ## Cross-Platform Deployment Skills install identically across Claude Code (via plugin marketplace commands), Claude.ai (drag-and-drop upload for paid plans), and the Claude API (programmatic upload). This means a skill authored once can be deployed to CLI-based developer workflows, browser-based knowledge work, and headless automation pipelines without modification. ## Plugin Marketplace Integration Claude Code users can install skills directly from the plugin marketplace with commands like `/plugin marketplace add anthropics/skills`. The marketplace provides versioned distribution, dependency resolution, and one-command installation, lowering the barrier to adopting community-contributed skills. ## Agent Skills Standard (agentskills.io) Anthropic has published the Agent Skills Standard at agentskills.io, defining a vendor-neutral specification for how AI agents should discover, load, and execute skills. This positions Skills not just as a Claude-specific feature but as a potential cross-model interoperability layer for the broader AI agent ecosystem.