> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentfacets.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Key Concepts

> Asset types, the manifest, text composition, MCP servers, and the facet lifecycle

This page introduces the core concepts behind Facets. For normative requirements, see the [Specification](/specification).

## Facets

A **facet** is a versioned collection of [assets](#assets) defined by a facet manifest (`facet.json`). What the author creates locally, what gets published to the registry, and what gets extracted after install.

## Assets

A discrete unit of content within a facet. Consisting of any combination of skills, agents, commands, and MCPservers.

<Columns col={2}>
  <Card title="Skills" href="/docs/learn/skills">
    Text assets that follow the [Agent Skills](https://agentskills.io/specification) specification.
  </Card>

  <Card title="Commands" href="/docs/learn/commands">
    Text assets that follow the [Agent Skills](https://agentskills.io/specification) specification.
  </Card>

  <Card title="Agents" href="/docs/learn/agents">
    Text assets that follow the [Agent Skills](https://agentskills.io/specification) specification.
  </Card>

  <Card title="Servers" href="/docs/learn/servers">
    A reference to an MCP server that is compliant with the [Model Context Protocol](https://modelcontextprotocol.io/specification/latest)
  </Card>
</Columns>