ai-elements-mcp-apps/dev.ai.elements.mcpapps

Package-level declarations

Types

What an app does with its views' requests; the chat-level part of McpAppHost (the view handles sizing, display modes and tool approval itself).

McpAppBridge

class McpAppBridge(client: McpClient, resource: McpAppResource, toolCallId: String, tool: JsonObject, host: McpAppHost, hostContext: JsonObject = JsonObject(emptyMap()), hostInfo: McpImplementation = McpImplementation("ai-elements-kotlin", "0.3.0"), send: suspend (JsonObject) -> Unit)

The host side of one MCP App view (MCP Apps 2026-01-26, §"Communication Protocol"): it answers the view's JSON-RPC over send / receive as an MCP server that proxies client — the connection of the server that owns the view — and drives the lifecycle (ui/initialize, tool input and result, host context, teardown).

McpAppCsp

data class McpAppCsp(val connectDomains: List<String> = emptyList(), val resourceDomains: List<String> = emptyList(), val frameDomains: List<String> = emptyList(), val baseUriDomains: List<String> = emptyList())

The origins a view may reach (MCP Apps McpUiResourceCsp). Empty lists are the secure default: no connections, no external resources, no nested frames, same-origin base URIs.

McpAppException

class McpAppException(message: String) : Exception

A view that cannot be shown: not a ui:// resource, not text/html;profile=mcp-app, or empty.

McpAppHost

interface McpAppHost

What the host does for a view. Every method has a safe default (decline, ignore), so a host implements only what it offers.

McpAppModelContext

data class McpAppModelContext(val toolCallId: String, val app: String, val content: JsonArray?, val structuredContent: JsonElement?)

What a view wants the model to know (ui/update-model-context): its latest content blocks and structuredContent. Attach toDataPart to the next user turn; each view's newest replaces its previous one.

McpAppResource

data class McpAppResource(val uri: String, val html: String, val csp: McpAppCsp = McpAppCsp(), val permissions: Set<String> = emptySet(), val prefersBorder: Boolean? = null, val domain: String? = null)

An MCP App view read from its server (resources/read of a ui:// URI, §"UI Resource Format").

McpAppSessions

class McpAppSessions(capacity: Int = 8)

The live views of a chat, by tool call. A view keeps running while it scrolls out of sight or its message recomposes — its sandbox, connection and state live here, not in the composition — and is torn down (ui/resource-teardown) when evicted (beyond capacity, least recently shown first) or on close. rememberMcpAppSessions closes them with the composition.

Functions

mcpAppRenderer

fun mcpAppRenderer(clientFor: (serverId: String) -> McpClient?, actions: McpAppActions, sessions: McpAppSessions): DataRenderer

Renders DataPart.MCP_APP parts — added by MCP tools that have a view (_meta.ui.resourceUri) — as their MCP App (McpAppView). clientFor returns the connection of the part's server (by the server id the part names; reuse the instances the agent uses); a part whose server is unknown renders nothing. The views live in sessions: keep one per chat screen.

McpAppsHost

@Composable

fun McpAppsHost(clientFor: (serverId: String) -> McpClient?, actions: McpAppActions, content: @Composable (renderer: DataRenderer) -> Unit)

MCP Apps for a chat screen: content gets the renderer for DataPart.MCP_APP (register it in AiElementsRenderers.data), and the views' dialogs — tool approvals, full screen — show at this level, whether or not their view is scrolled into sight. Views are torn down with this.

McpAppView

@Composable

fun McpAppView(client: McpClient, resourceUri: String, toolCallId: String, tool: JsonObject, input: JsonObject, result: JsonObject?, actions: McpAppActions, modifier: Modifier = Modifier, sessions: McpAppSessions = rememberMcpAppSessions(), maxHeight: Dp = 600.dp, originKey: String = client.url)

Shows the MCP App view resourceUri of one tool call: it reads the view from client (the connection of the server that owns it), runs it in a sandbox and connects it to the chat through actions. input is the call's arguments and result its CallToolResult once it returns.

readMcpApp

suspend fun McpClient.readMcpApp(uri: String): McpAppResource

Read and validate the MCP App view at uri.

rememberMcpAppSessions

@Composable

fun rememberMcpAppSessions(capacity: Int = 8): McpAppSessions

McpAppSessions that close when this leaves the composition.