Package-level declarations

Types

class Chat(val id: String = "chat", initialMessages: List<UIMessage> = emptyList(), transport: ChatTransport)

data class ChatRequest(val messages: List<UIMessage>, val body: Map<String, JsonElement> = emptyMap(), val headers: Map<String, String> = emptyMap())

ChatSession

class ChatSession(chat: Chat)

ChatState

data class ChatState(val id: String, val messages: List<UIMessage> = emptyList(), val status: ChatStatus = ChatStatus.Ready, val error: Throwable? = null)

ChatStatus

enum ChatStatus : Enum<ChatStatus>

ChatTransport

interface ChatTransport

DefaultChatTransport

class DefaultChatTransport(delegate: ChatTransport) : ChatTransport

DirectChatTransport

class DirectChatTransport(handler: (ChatRequest) -> Flow<UIMessage>) : ChatTransport

SafeValidateUIMessagesResult

sealed interface SafeValidateUIMessagesResult

ServerResponseWriter

interface ServerResponseWriter

TextStreamChatTransport

class TextStreamChatTransport(handler: (ChatRequest) -> Flow<String>, assistantMessageId: (ChatRequest) -> String = { request -> getResponseUiMessageId(request.messages) }) : ChatTransport

TextStreamResponse

data class TextStreamResponse(val textStream: Flow<String>, val status: Int = 200, val headers: Map<String, String> = textStreamHeaders())

TextUIPartState

@Serializable

enum TextUIPartState : Enum<TextUIPartState>

Streaming-vs-final state for UIMessagePart.Text and UIMessagePart.Reasoning (per historical parity gap #30, mirrors v6's TextUIPart.state: 'streaming' | 'done'). Renderers use this to drive a typing cursor / fade animation while the model is still producing the part, and to commit a final layout pass on Done.

ToolCallState

@Serializable

enum ToolCallState : Enum<ToolCallState>

Tool call lifecycle in the UI. v6 names — input-streaming / input-available / output-available, NOT v5's partial-call / call / result.

ToolPartHandlerRegistry

class ToolPartHandlerRegistry<TRenderResult>

Registry of per-tool renderers. The SDK is UI-framework-agnostic — the registry holds renderer functions that take UIToolInvocation. An application can supply Compose composables, SwiftUI bridge closures, server-rendered nodes, or any other renderer value.

UIMessage

@Serializable

data class UIMessage(val id: String, val role: UIMessageRole, val parts: List<UIMessagePart>, val createdAtMs: Long = 0, val metadata: Map<String, JsonElement>? = null)

UI-shape message — what the chat surface renders. Carries an ordered list of UIMessageParts (Vercel AI SDK v6 message-parts model). The conversion from ai.torad.aisdk.StreamEvent flow into a growing list of these messages happens in streamToUiMessages.

UIMessagePart

@Serializable

sealed interface UIMessagePart

UIMessageRole

@Serializable

enum UIMessageRole : Enum<UIMessageRole>

UIMessageStreamResponse

data class UIMessageStreamResponse(val stream: Flow<UIMessage>, val status: Int = 200, val headers: Map<String, String> = uiMessageStreamHeaders())

UIMessageStreamWriter

interface UIMessageStreamWriter

UIToolInvocation

class UIToolInvocation<TInput, TOutput>(val toolCallId: String, val toolName: String, val state: ToolCallState, val input: TInput?, val output: TOutput?, val error: String?)

Typed invocation handle — what a per-tool renderer receives. Carries the typed input + output via the tool's own serializers.

Functions

asSession

fun Chat.asSession(): ChatSession

buildToolPartHandlerRegistry

fun <TRenderResult> buildToolPartHandlerRegistry(fallback: (UIMessagePart.ToolUI) -> TRenderResult, block: ToolPartHandlerRegistry.Builder<TRenderResult>.() -> Unit): ToolPartHandlerRegistry<TRenderResult>

Top-level builder for ToolPartHandlerRegistry.

chatSession

fun chatSession(id: String = "chat", initialMessages: List<UIMessage> = emptyList(), transport: ChatTransport): ChatSession

convertToModelMessages

fun convertToModelMessages(messages: List<UIMessage>, ignoreIncompleteToolCalls: Boolean = false): List<ModelMessage>

Convert a list of UI-shape UIMessages back into the model-shape ModelMessage list the LLM expects on the next turn. Mirrors v6's convertToModelMessages (per historical parity gap #5).

createTextStreamResponse

fun createTextStreamResponse(textStream: Flow<String>, status: Int = 200, headers: Map<String, String> = textStreamHeaders()): TextStreamResponse

createUiMessageStream

fun createUiMessageStream(onError: (Throwable) -> UIMessage = { throwable -> UIMessage( id = "error", role = UIMessageRole.Assistant, parts = listOf(UIMessagePart.Error(throwable.message ?: "stream failed")), ) }, execute: suspend UIMessageStreamWriter.() -> Unit): Flow<UIMessage>

createUiMessageStreamResponse

fun createUiMessageStreamResponse(stream: Flow<UIMessage>, status: Int = 200, headers: Map<String, String> = uiMessageStreamHeaders()): UIMessageStreamResponse

dataAs

fun <TData> dataAs(part: UIMessagePart.Data, serializer: KSerializer<TData>): TData

dataAs

inline fun <TData> UIMessagePart.Data.dataAs(): TData

dynamicInputAs

fun <TInput> dynamicInputAs(part: UIMessagePart.DynamicToolUI, serializer: KSerializer<TInput>): TInput?

dynamicOutputAs

fun <TOutput> dynamicOutputAs(part: UIMessagePart.DynamicToolUI, serializer: KSerializer<TOutput>): TOutput?

getResponseUiMessageId

fun getResponseUiMessageId(messages: List<UIMessage>, createId: () -> String = { "msg_${messages.size + 1}" }): String

handleUiMessageStreamFinish

fun handleUiMessageStreamFinish(messages: List<UIMessage>, onFinish: (List<UIMessage>) -> Unit)

inputAs

fun <TInput> inputAs(part: UIMessagePart.ToolUI, serializer: KSerializer<TInput>): TInput?

Type-safe extraction of input args while the tool is mid-flight or complete. Returns null if input isn't yet available.

inputAs

inline fun <TInput> UIMessagePart.DynamicToolUI.inputAs(): TInput?

inline fun <TInput> UIMessagePart.ToolUI.inputAs(): TInput?

lastAssistantMessageIsCompleteWithApprovalResponses

fun lastAssistantMessageIsCompleteWithApprovalResponses(messages: List<UIMessage>): Boolean

lastAssistantMessageIsCompleteWithToolCalls

fun lastAssistantMessageIsCompleteWithToolCalls(messages: List<UIMessage>): Boolean

metadataAs

inline fun <TMetadata> UIMessage.metadataAs(name: String): TMetadata?

fun <TMetadata> UIMessage.metadataAs(name: String, serializer: KSerializer<TMetadata>): TMetadata?

outputAs

fun <TOutput> outputAs(part: UIMessagePart.ToolUI, serializer: KSerializer<TOutput>): TOutput?

Type-safe extraction at the UI render seam. Pulls a typed TOutput out of UIMessagePart.ToolUI.output. Returns null if state isn't OutputAvailable (caller should branch on state first).

outputAs

inline fun <TOutput> UIMessagePart.DynamicToolUI.outputAs(): TOutput?

inline fun <TOutput> UIMessagePart.ToolUI.outputAs(): TOutput?

pipeTextStreamToResponse

suspend fun pipeTextStreamToResponse(textStream: Flow<String>, response: ServerResponseWriter, status: Int = 200, headers: Map<String, String> = textStreamHeaders())

pipeUiMessageStreamToResponse

suspend fun pipeUiMessageStreamToResponse(stream: Flow<UIMessage>, response: ServerResponseWriter, encoder: (UIMessage) -> String = { it.toString() }, status: Int = 200, headers: Map<String, String> = uiMessageStreamHeaders())

readUiMessageStream

fun readUiMessageStream(stream: Flow<UIMessage>): Flow<UIMessage>

safeValidateUIMessages

fun safeValidateUIMessages(messages: List<UIMessage>?): SafeValidateUIMessagesResult

streamToUiMessages

fun streamToUiMessages(events: Flow<StreamEvent>, assistantMessageId: String): Flow<UIMessage>

Convert a raw agent StreamEvent flow into a flow of growing UIMessage snapshots. Each emission is the current full state of the assistant message being built — caller's StateFlow<List<UIMessage>> just replaces the in-flight message on each emission.

textStreamFromEvents

fun textStreamFromEvents(events: Flow<StreamEvent>): Flow<String>

textStreamHeaders

fun textStreamHeaders(): Map<String, String>

toUIMessageStream

fun toUIMessageStream(events: Flow<StreamEvent>): Flow<JsonObject>

Bridge an agent StreamEvent flow to the v6 UI-message-stream wire protocol: each emission is a UIMessageChunk JSON object (e.g. { "type": "text-delta", "id": "...", "delta": "..." }) ready to be framed as an SSE data: line and consumed by a JS useChat client. Events with no wire counterpart (response-metadata, tool-input-end, raw) are dropped.

transformTextToUiMessageStream

fun transformTextToUiMessageStream(textStream: Flow<String>, assistantMessageId: String, metadata: Map<String, JsonElement>? = null): Flow<UIMessage>

uiMessageStreamError

fun uiMessageStreamError(message: String, cause: Throwable? = null): UiMessageStreamError

uiMessageStreamHeaders

fun uiMessageStreamHeaders(): Map<String, String>

validateUIMessages

fun validateUIMessages(messages: List<UIMessage>)

validateUiMessages

fun validateUiMessages(messages: List<UIMessage>)