Anthropic Skills - Anthropic's skill system for Claude.

The technical principles of Anthropic Skills

• File structure and metadata parsingEach Skill is a self-contained folder, with the core being... SKILL.mdThe top of the file uses YAML Frontmatter to declare metadata (name,description,version (etc.), below which are instructions, examples, and constraint rules written in Markdown. When Claude parses, it first reads the Frontmatter for route matching, and then loads the body as the behavior script.
• Context Injection and Hints EngineeringSkill is essentially a pluggable "system prompt fragment". After installation, Claude dynamically injects the content of SKILL.md into the model context during the dialogue initialization phase, concatenating it with the basic system prompts. This is equivalent to adding a task-specific "role card" and "working memory" to Claude, allowing it to follow predefined inference chains and output formats in specific domains.
• Dynamic loading and on-demand activationClaude performs intent matching based on the semantics of the user's query. When a task is detected that matches a certain Skill... description The context injection for a Skill is triggered only when it matches the example scenario. This on-demand activation mechanism avoids unnecessary use of the context window and supports chained calls to multiple Skills (e.g., using the first Skill in the example scenario). skill-creator Generate a new Skill, then load and execute it immediately.
• Execution chain: Commands → Tools → VerificationThe Markdown directives in the Skill include text strategies and can reference code scripts, JSON schemas, or resource files in the same directory. Claude executes the steps described in the Skill: first understanding the target, then invoking built-in tools (such as file reading and writing, code execution, and browser operations), and self-checking the output according to the "validation rules" defined in the Skill. For example... webapp-testing It will drive Playwright to perform real browser interaction and take screenshots for verification.
• Integration with Agent Skills standards and MCPAnthropic designed Skills as an implementation of the open Agent Skills standard (agentskills.io).mcp-builder Skill further bridges the Model Context Protocol (MCP), guiding Claude to generate server code that conforms to the MCP specification. This enables external APIs and data sources to register as Claude's context tools in a standardized way, achieving an extension from "static instructions" to a "dynamic tool ecosystem".

How to use Anthropic Skills

• Claude Code command-line installation: Execute in the terminal /plugin marketplace add anthropics/skills Register on the official market and use /plugin install document-skills@anthropic-agent-skills Install an office four-piece set, or use /plugin install example-skills@anthropic-agent-skills Install the remaining sample skills. Once installed, simply mention the skill name in the dialog to trigger it, for example: "Use the PDF skill to extract form fields from this document".
• Claude web versionPaid subscribers have all sample skills pre-installed. Simply describe the task in the chat, and Claude will automatically match and load the corresponding skill. To upload a custom skill, go to the Skills panel in settings and upload the packaged skill. .skill The system will parse the files or folders within them. SKILL.md And dynamically inject the context.
• Claude API IntegrationSpecify in the request via the Skills API skill_id Alternatively, you can upload a custom Skill package to endow API-level Claude instances with domain-specific capabilities. This is suitable for embedding capabilities such as document generation and web testing into your own product workflows.
• Create a custom Skil:Copy from the repository template-skill Folder, Modify SKILL.md Add examples and constraint rules to the YAML Frontmatter (name, description) and body directives. Save to ~/.claude/skills/ Directory or package as .skill Once the file is uploaded, it can be accessed by name in the chat.

Key information and usage requirements for Anthropic Skills

• Open source and licensing statusThe example skill is fully open source using Apache 2.0; the four Office suites (docx/xlsx/pptx/pdf) are source-available and can be read and referenced, but with limited licensing.
• Core document specificationsEach Skill must be a self-contained folder, with the root directory containing... SKILL.mdThe top of the file must contain a YAML Frontmatter declaration, at least... name(Unique Identifier) and description(Triggering scenario), the main text uses Markdown to write instructions, examples and constraints.
• Installation platform requirements:
  • Claude Code command line: via /plugin marketplace add Install after registering with the marketplace;
  • Claude.ai website: A paid subscription is required to unlock all sample skills;
  • Claude API: Requires a valid API key and must be bound via the Skills API.
• Category and Package NameThe official team is divided into two groups:document-skills(Office four-piece set) and example-skills(The remaining 13 include skill-creator), the full package name must be specified in the command line during installation.
• Custom Skill PathClaude Code is read by default. ~/.claude/skills/ The folder under the directory; Claude.ai supports uploading. .skill Compressed package or single file; API supports dynamic mounting upon request.

The core advantages of Anthropic Skills

• Dynamic on-demand loadingAutomatically matches and injects the corresponding Skill based on task semantics, avoiding wasted context windows and supporting multi-Skill chain collaboration.
• Standardized lightweight structureOnly one YAML Frontmatter is needed. SKILL.md The file can define complete behavior, enabling zero-configuration integration.
• Comprehensive scene coverageIt includes 17 production-grade skills such as office suite, web testing, MCP building, front-end design, and algorithm art.
• Meta Skills Unlimited Expansion:pass skill-creator Custom skills can be generated with zero barriers, enabling unlimited reuse of personal and corporate workflows.
• Seamless compatibility across three platformsThe same set of skills can be used consistently in the Claude Code command line, the Claude.ai web interface, and the API.
• Open Ecosystem ProtocolAdhere to the Agent Skills standard and integrate with the MCP protocol to ensure interoperability between custom tools and the external API ecosystem.

Anthropic Skills project address

• GitHub repositoryhttps://github.com/anthropics/skills

Comparison of Anthropic Skills with similar products

Application scenarios of Anthropic Skills

• Document automation officeThis tool uses a four-format library (docx, xlsx, pptx, and pdf) to batch generate contracts, financial statements, and presentations, automatically handling styles, formulas, charts, and red lines for review.
• Web application end-to-end testing: Drive Playwright to perform automated testing, screenshot comparison and interaction verification through webapp-testing, covering front-end functional regression and UI consistency checks.
• Custom tool and protocol developmentUse mcp-builder to write an MCP server that connects to a private API, or use skill-creator to encapsulate internal workflows into reusable, proprietary skills.
• Quickly build front-end interfaceIt outputs React + Tailwind code based on frontend-design and web-artifacts-builder, enabling rapid construction of landing pages, backend panels, and interactive components.
• Brand visual system implementationUse brand-guidelines and theme-factory to synchronize corporate colors, fonts, and typography guidelines to documents, web pages, and slides with one click, maintaining visual consistency across all channels.