# `Phantom.UI`
[🔗](https://github.com/dbernheisel/phantom_mcp/blob/main/lib/phantom/ui.ex#L1)

Metadata for the MCP Apps extension (`io.modelcontextprotocol/ui`).

MCP Apps allow servers to deliver interactive HTML user interfaces
that render inside MCP hosts as sandboxed iframes. This module
encapsulates the UI metadata for both tools (linking to a UI resource)
and resources (CSP, permissions, sandbox configuration).

See https://apps.extensions.modelcontextprotocol.io/

# `t`

```elixir
@type t() :: %Phantom.UI{
  base_uri_domains: [String.t()] | nil,
  connect_domains: [String.t()] | nil,
  domain: String.t() | nil,
  frame_domains: [String.t()] | nil,
  permissions: [atom()] | nil,
  prefers_border: boolean() | nil,
  resource_domains: [String.t()] | nil,
  resource_uri: String.t() | nil,
  visibility: [visibility()]
}
```

# `visibility`

```elixir
@type visibility() :: :model | :app
```

# `build`

```elixir
@spec build(Keyword.t() | map()) :: t() | nil
```

Build a `%Phantom.UI{}` from a keyword list or map.

Returns `nil` if no UI-related attributes are present.

Raises `ArgumentError` if `visibility` contains unknown values.
Valid visibility values are `:model` and `:app`.

# `model_visible?`

```elixir
@spec model_visible?(Phantom.Tool.t()) :: boolean()
```

Returns `true` if the tool should appear in `tools/list` (visible to the model).

Tools without UI metadata are always visible. Tools with UI are visible
when their visibility list includes `:model`.

# `to_resource_meta`

```elixir
@spec to_resource_meta(t() | nil) :: %{ui: map()} | nil
```

Produce the `_meta` map for a resource's JSON representation.

Includes CSP domains, permissions, domain, and border preference.
Returns `nil` when no resource-side metadata is present.

# `to_tool_meta`

```elixir
@spec to_tool_meta(t() | nil) :: %{ui: map()} | nil
```

Produce the `_meta` map for a tool's JSON representation.

Returns `nil` when no UI is configured, which gets stripped by `remove_nils`.
Visibility atoms are serialized to strings for the JSON wire format.

---

*Consult [api-reference.md](api-reference.md) for complete listing*