Streaming Events

ChatStreamEvent

sealed interface ChatStreamEvent — Package: com.chatbase.sdk.streaming Events emitted by sendMessageStream() and retryStream().

Text Events
Tool Events
Step & Lifecycle
Error

TextStart

A new text block is starting.

data class TextStart(val id: String) : ChatStreamEvent

TextDelta

An incremental text chunk. Append to the current text.

data class TextDelta(val id: String, val delta: String) : ChatStreamEvent

TextEnd

The current text block is complete.

data class TextEnd(val id: String) : ChatStreamEvent

ToolInputStart

A tool call is starting — input will stream incrementally.

data class ToolInputStart(
    val toolCallId: String,
    val toolName: String
) : ChatStreamEvent

ToolInputDelta

Incremental tool input text.

data class ToolInputDelta(
    val toolCallId: String,
    val inputTextDelta: String
) : ChatStreamEvent

ToolInputAvailable

The tool call’s full input is ready.

data class ToolInputAvailable(
    val toolCallId: String,
    val toolName: String,
    val input: JsonElement
) : ChatStreamEvent

Read the full input object directly from this event — no need to concatenate preceding deltas.

ToolOutputAvailable

A tool’s execution result is available.

data class ToolOutputAvailable(
    val toolCallId: String,
    val output: JsonElement
) : ChatStreamEvent

StepStart / StepFinish

object StepStart : ChatStreamEvent
object StepFinish : ChatStreamEvent

Start

The message stream is starting.

data class Start(
    val messageId: String?,
    val messageMetadata: StreamMessageMetadata?
) : ChatStreamEvent

Finish

The stream is complete.

data class Finish(
    val finishReason: String,
    val messageMetadata: StreamMessageMetadata?
) : ChatStreamEvent

finishReason is usually "stop", "error", or "tool-calls". Other values ("length", "content-filter", "other", "unknown") are possible and map to FinishReason.UNKNOWN in the aggregated ChatResponse.

MessageMetadataEvent

Updated metadata arrived mid-stream.

data class MessageMetadataEvent(
    val messageMetadata: StreamMessageMetadata
) : ChatStreamEvent

Error

An error occurred during streaming.

data class Error(val exception: ChatbaseException) : ChatStreamEvent

The exception may be an ApiException or NetworkException. See Error Handling.

StreamMessageMetadata

data class StreamMessageMetadata — Package: com.chatbase.sdk.streaming Accompanies Start, Finish, and MessageMetadataEvent events.

data class StreamMessageMetadata(
    val messageId: String?,
    val userMessageId: String?,
    val conversationId: String?,
    val usage: StreamUsage?
)

StreamUsage

data class StreamUsage(val credits: Double = 0.0)

ToolCallInfo

data class ToolCallInfo — Package: com.chatbase.sdk Passed to the onToolCall callback before handler execution.

data class ToolCallInfo(
    val toolCallId: String,
    val toolName: String,
    val input: JsonElement
)

fun inputAsMap(): Map<String, Any?>

Parse the JSON input into a Map<String, Any?> for easy access.

ToolResultInfo

data class ToolResultInfo — Package: com.chatbase.sdk Passed to the onToolResult callback after handler execution.

data class ToolResultInfo(
    val toolCallId: String,
    val toolName: String,
    val output: Any
)

fun outputAsString(): String

Serialize the output to a JSON string.

Getting Started

Reference

ChatStreamEvent

TextStart

TextDelta

TextEnd

ToolInputStart

ToolInputDelta

ToolInputAvailable

ToolOutputAvailable

StepStart / StepFinish

Start

Finish

MessageMetadataEvent

Error

StreamMessageMetadata

StreamUsage

ToolCallInfo

ToolResultInfo

​ChatStreamEvent

​TextStart

​TextDelta

​TextEnd

​ToolInputStart

​ToolInputDelta

​ToolInputAvailable

​ToolOutputAvailable

​StepStart / StepFinish

​Start

​Finish

​MessageMetadataEvent

​Error

​StreamMessageMetadata

​StreamUsage

​ToolCallInfo

​ToolResultInfo

ChatStreamEvent

TextStart

TextDelta

TextEnd

ToolInputStart

ToolInputDelta

ToolInputAvailable

ToolOutputAvailable

StepStart / StepFinish

Start

Finish

MessageMetadataEvent

Error

StreamMessageMetadata

StreamUsage

ToolCallInfo

ToolResultInfo