ai-elements-chat/dev.ai.elements.core.model/DataPart/Companion

Companion

Properties

A2UI (open generative-UI protocol) messages as a JSON array: agent-to-renderer messages on assistant turns, renderer-to-agent messages (a user action) on user turns. Transports map their A2UI binding onto it (AG-UI a2ui-surface activities, A2A application/a2ui+json parts).

A2UI_DATA_MODEL

const val A2UI_DATA_MODEL: String

The renderer's data models (A2UI renderer_data_model.json) sent along with an A2UI action.

A2UI_MEDIA_TYPE

const val A2UI_MEDIA_TYPE: String

The A2UI media type in transports.

MCP_APP

const val MCP_APP: String

An MCP App (MCP Apps extension io.modelcontextprotocol/ui) for a tool call, as a JSON object: server (id), serverName, resourceUri (ui://…), tool (the MCP tool), toolCallId, input and, once the call returns, result (the MCP CallToolResult). In-process only: the MCP client that ran the tool adds it.

MODEL_CONTEXT

const val MODEL_CONTEXT: String

Context for the model on a user turn, as {"description": …, "value": …} (e.g. what an MCP App shows, from ui/update-model-context). Not shown as the user's words: on-device models get it as text before the turn, AG-UI as RunAgentInput.context, the AI SDK as a data-model-context part.

STATE

const val STATE: String

The name of the agent's shared state (a JSON object the agent keeps in sync with the UI, e.g. AG-UI STATE_SNAPSHOT / STATE_DELTA). Its plan / task keys use the data shapes above.