Enum StreamEvent 

#[non_exhaustive]
pub enum StreamEvent {
    Start {
        call_id: String,
    },
    StartStep {
        step_number: u32,
        runtime_context: Option<JsonValue>,
        tools_context: Option<JsonValue>,
        model: ModelIdentity,
        request: StepRequest,
        warnings: Vec<Warning>,
    },
    TextStart {
        id: PartId,
        provider_metadata: Option<ProviderMetadata>,
    },
    TextDelta {
        id: PartId,
        text: String,
        provider_metadata: Option<ProviderMetadata>,
    },
    TextEnd {
        id: PartId,
        provider_metadata: Option<ProviderMetadata>,
    },
    ReasoningStart {
        id: PartId,
        provider_metadata: Option<ProviderMetadata>,
    },
    ReasoningDelta {
        id: PartId,
        text: String,
        provider_metadata: Option<ProviderMetadata>,
    },
    ReasoningEnd {
        id: PartId,
        provider_metadata: Option<ProviderMetadata>,
    },
    ReasoningFile(GeneratedFile),
    File(GeneratedFile),
    Source(Source),
    Custom {
        kind: CustomKind,
        provider_metadata: Option<ProviderMetadata>,
    },
    ToolInputStart {
        id: ToolCallId,
        tool_name: ToolName,
        provider_executed: bool,
        dynamic: bool,
        title: Option<String>,
        provider_metadata: Option<ProviderMetadata>,
    },
    ToolInputDelta {
        id: ToolCallId,
        delta: String,
        provider_metadata: Option<ProviderMetadata>,
    },
    ToolInputEnd {
        id: ToolCallId,
        provider_metadata: Option<ProviderMetadata>,
    },
    ToolCall(ParsedToolCall),
    ToolResult(ToolResult),
    ToolError(ToolExecutionError),
    ToolApprovalRequest(ToolApprovalRequestContent),
    ToolApprovalResponse(ToolApprovalResponseContent),
    ToolOutputDenied(ToolOutputDenied),
    FinishStep {
        step_number: u32,
        finish_reason: FinishReason,
        usage: Usage,
        response: StepResponse,
        provider_metadata: Option<ProviderMetadata>,
        performance: StepPerformance,
    },
    Finish {
        finish_reason: FinishReason,
        total_usage: Usage,
    },
    Error {
        error: StreamErrorInfo,
    },
    Abort,
    RetryAttempt {
        step_number: u32,
        attempt: u32,
        request: StepRequest,
        warnings: Vec<Warning>,
    },
    Raw {
        raw_value: JsonValue,
    },
}

One event of a text stream. Serializable, so applications can forward events over SSE or WebSocket frames unchanged.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Start

The call started.

Fields

call_id: String

Call id.

StartStep

A step started.

Fields

step_number: u32

Zero-based step index.

runtime_context: Option<JsonValue>

Application state used for this step.

tools_context: Option<JsonValue>

Shared tool context used for this step.

model: ModelIdentity

The model handling the step.

request: StepRequest

Request metadata.

warnings: Vec<Warning>

Warnings from the adapter.

TextStart

Start of a text part.

Fields

id: PartId

Part id.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

TextDelta

Text increment.

Fields

id: PartId

Part id.

text: String

Appended text.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

TextEnd

End of a text part.

Fields

id: PartId

Part id.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ReasoningStart

Start of a reasoning part.

Fields

id: PartId

Part id.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ReasoningDelta

Reasoning increment.

Fields

id: PartId

Part id.

text: String

Appended text.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ReasoningEnd

End of a reasoning part.

Fields

id: PartId

Part id.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ReasoningFile(GeneratedFile)

A reasoning artifact stored as a file.

File(GeneratedFile)

A generated file.

Source(Source)

A citation source.

Custom

Provider-specific content.

Fields

kind: CustomKind

Kind of the content.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ToolInputStart

Start of streamed tool input.

Fields

id: ToolCallId

Tool call id.

tool_name: ToolName

Tool name.

provider_executed: bool

Whether the provider executes the tool.

dynamic: bool

Whether the tool is dynamic.

title: Option<String>

Display title.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ToolInputDelta

Tool input increment (raw JSON text).

Fields

id: ToolCallId

Tool call id.

delta: String

Appended JSON text.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ToolInputEnd

End of streamed tool input.

Fields

id: ToolCallId

Tool call id.

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

ToolCall(ParsedToolCall)

A parsed tool call.

ToolResult(ToolResult)

A tool result (may be preliminary).

ToolError(ToolExecutionError)

A tool error.

ToolApprovalRequest(ToolApprovalRequestContent)

A request to approve a tool call.

ToolApprovalResponse(ToolApprovalResponseContent)

An automatic approval decision.

ToolOutputDenied(ToolOutputDenied)

A denied tool call.

FinishStep

A step finished.

Fields

step_number: u32

Zero-based step index.

finish_reason: FinishReason

Finish reason.

usage: Usage

Usage of the step.

response: StepResponse

Response metadata (without messages).

provider_metadata: Option<ProviderMetadata>

Provider-specific metadata.

performance: StepPerformance

Timing and throughput of the step.

Finish

The call finished.

Fields

finish_reason: FinishReason

Finish reason of the last step.

total_usage: Usage

Usage summed over all steps.

Error

An error occurred (the stream may continue after a retry).

Fields

error: StreamErrorInfo

The error.

Abort

The call was aborted by cancellation.

RetryAttempt

The model call of the current step was retried after a stream error. Content emitted by the previous attempt stays in the stream but is excluded from the step result.

Fields

step_number: u32

Zero-based step index.

attempt: u32

One-based retry attempt number.

request: StepRequest

Request metadata of the new attempt.

warnings: Vec<Warning>

Warnings from the new attempt’s stream start.

Raw

A raw provider chunk (only with include_raw_chunks).

Fields

raw_value: JsonValue

The chunk.

Implementations

impl StreamEvent

pub fn kind_name(&self) -> &'static str

Returns the wire name of the variant.

pub fn as_text_delta(&self) -> Option<&str>

Returns the text of a text delta.

Trait Implementations

impl Clone for StreamEvent

fn clone(&self) -> StreamEvent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StreamEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StreamEvent

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for StreamEvent

fn eq(&self, other: &StreamEvent) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for StreamEvent

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for StreamEvent