Skills API Documentation
FreeAPI integration guide
FreeFree tier
About Skills API Documentation
Agent Skills extend Claude's capabilities through organized folders of instructions, scripts, and resources. This guide shows how to use both pre-built and custom Skills with the Claude API, integrating them through the code execution tool within the Messages API. Skills can be sourced from Anthropic (pre-built for common document types like pptx, xlsx, docx, pdf) or created as custom Skills managed via the Skills API. Both types share the same container-based execution environment and require a skill_id, type, and optional version parameter.
Key Features
Pre-built Anthropic Skills for document types (pptx, xlsx, docx, pdf)
Custom Skills uploaded and managed via Skills API
Integration with Messages API through code execution tool
Version management with date-based or epoch timestamps
Container-based execution environment for skills
Pros & Cons
Pros
- Extends Claude with modular, reusable skill packages
- Supports both pre-built and custom skills for flexibility
- Seamless integration with existing Messages API and code execution tool
Cons
- Requires understanding of code execution tool and container setup
- Dependency on Anthropic infrastructure for skill execution
- Custom skills need to be explicitly managed through the Skills API
Best For
Automating document generation and processing (e.g., creating presentations, spreadsheets)Building custom agent skills for domain-specific workflowsEnterprise deployment of reusable, modular skill packages
FAQ
What are Agent Skills?
Agent Skills extend Claude's capabilities through organized folders of instructions, scripts, and resources. They can be pre-built by Anthropic or custom.
How do I use Skills with the API?
Skills integrate with the Messages API through the code execution tool. You specify Skills in the container parameter with a skill_id, type, and optional version.
What types of Skills are available?
There are two types: Anthropic Skills (pre-built, with short names like pptx, xlsx, docx, pdf) and Custom Skills (uploaded and managed via the Skills API, private to your workspace).