ai-elements-chat/dev.ai.elements.core.model/Message

Message

@Serializable

data class Message(val id: String, val role: Role, val parts: List<Part> = emptyList(), val createdAt: Long = 0, val usage: Usage? = null, val alternatives: List<Message> = emptyList(), val metadata: JsonObject? = null)(source)

A chat message: an ordered list of Parts, the same shape as the AI SDK UIMessage. Assistant messages usually interleave reasoning, tool calls and text across several agent steps.

Constructors

constructor(id: String, role: Role, parts: List<Part> = emptyList(), createdAt: Long = 0, usage: Usage? = null, alternatives: List<Message> = emptyList(), metadata: JsonObject? = null)

Properties

val alternatives: List<Message>

Other versions of this reply (AI Elements <Branch>): regenerating keeps the previous answer here instead of discarding it. Oldest first.

val createdAt: Long

val isStreaming: Boolean

val metadata: JsonObject?

App- or protocol-defined metadata (AI SDK UIMessage.metadata), e.g. the A2A contextId / taskId a remote agent's reply belongs to.

val parts: List<Part>

val text: String

Concatenated text of all TextParts.

val usage: Usage?

val versionIndex: Int

0-based position of this version within versions.

val versions: List<Message>

All versions in creation order, this one included.

Functions

finishStreaming

fun Message.finishStreaming(now: Long): Message

Close every still-streaming part (end of turn, stop, or error).

fun Message.reduce(event: ChatEvent, now: Long): Message

Folds one ChatEvent into the assistant Message. Pure, so it is trivially unit-testable and every backend shares the exact same message semantics.