Introducing Agent Skills

Summary

Agent Skills are folders containing instructions, scripts, and resources that Claude loads when relevant to specialized tasks, enabling custom expertise across Claude apps, Claude Code, and the API. The system scans available skills, loads only the minimal information and files needed, and can combine multiple skills automatically. Skills may include executable code, and API use requires the Code Execution Tool beta; developers can manage versions through the /v1/skills endpoint and Claude Console. Users can build skills with the skill-creator workflow or install them through the anthropics/skills marketplace, while organization-wide management and a partner-built directory were added in the December 18, 2025 update. The post presents Skills as composable, portable, efficient, and powerful, but cautions that code-executing skills should come from trusted sources to protect data.

Takeaways

1. 1

   Skills use a shared format across Claude apps, Claude Code, and the API, so a skill can be built once and used across those products.

2. 2

   The Messages API supports Agent Skills through the Code Execution Tool beta, with /v1/skills providing programmatic skill versioning and management.

3. 3

   Skills can execute code, so the post advises using trusted sources to help keep data safe.