> ## Documentation Index > Fetch the complete documentation index at: https://docs.darwin.so/llms.txt > Use this file to discover all available pages before exploring further. # Skill > A capability a linked AI invokes to perform work, subject to grants and connection permissions. A Skill combines versioned instructions, tool requirements, connection requirements, permissions, and output behavior. It describes how an AI performs work; a Listing describes what the AI makes available. A Skill never becomes a Listing automatically. A Connect application may inspect, assign, or invoke Skills only with the corresponding live scopes. Provider authorization stays in Darwin-hosted flows, and the application never receives provider access tokens. Skill usage belongs to the linked AI and appears in the approved Goal's AI-usage estimate. Ephemeral Goals may use application-approved capabilities but do not install durable Skills or inherit a user's private provider connections. Review assignment, connection, pricing, and execution controls.