> ## 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.

# Adapters

> How facets reach your AI tool

An adapter connects facets to one AI coding tool. It knows where that tool keeps each kind of asset: files for skills, agents, and commands, and configuration entries for MCP servers. Install one adapter per tool you use, then every facet you add materializes into all of them.

Adapters are installed per machine, not per project:

```sh theme={"theme":{"light":"github-light","dark":"github-dark"}}
facet adapter add claude-code   # or: opencode, codex
facet adapter list
```

See [`facet adapter add`](/cli/adapters/add) for sources, versions, and compatibility recovery.

## Where assets land

Text assets are written at project scope, inside your checkout, so they travel with the repository. MCP servers land in configuration instead, covered below.

<ResponseField name="claude-code" type="first-party">
  `.claude/skills/<name>/SKILL.md`, `.claude/agents/<name>.md`, `.claude/commands/<name>.md`
</ResponseField>

<ResponseField name="opencode" type="first-party">
  `.opencode/skills/<name>/SKILL.md`, `.opencode/agents/<name>.md`, `.opencode/commands/<name>.md`
</ResponseField>

<ResponseField name="codex" type="first-party">
  `.agents/skills/<name>/SKILL.md`, `.agents/commands/<name>.md`, and `.codex/agents/<name>.toml`
</ResponseField>

The name on disk is the [effective name](/specification/materialization#two-identities), which is the name your project chose if you aliased the text asset.

## Where MCP configuration lands

<ResponseField name="claude-code" type="first-party">
  `.mcp.json`
</ResponseField>

<ResponseField name="opencode" type="first-party">
  Whichever of `.opencode/opencode.jsonc`, `.opencode/opencode.json`, `opencode.jsonc`, or `opencode.json` already holds your servers
</ResponseField>

<ResponseField name="codex" type="first-party">
  `.codex/config.toml`
</ResponseField>

Your unrelated settings, comments, and any server entry the project does not own are preserved. See [MCP servers](/docs/learn/mcp-servers).

## Building your own

An adapter is a small npm package that plans file changes and returns them; the CLI performs every write. See the [Custom adapters guide](/guides/custom-adapters) to build one, and the [Adapter SDK reference](/reference/adapter-sdk) for the contract.

## Further reading

* [`facet adapter add`](/cli/adapters/add)
* [Set up your environment](/guides/setup)