Enum StreamEvent 

#[non_exhaustive]
pub enum StreamEvent {
    ContentDelta(String),
    ReasoningDelta(String),
    ReasoningDetailsDelta(Vec<ReasoningDetail>),
    Done {
        tool_calls: Vec<ToolCall>,
        finish_reason: Option<FinishReason>,
        usage: Option<ResponseUsage>,
        id: String,
        model: String,
    },
    Error(OpenRouterError),
}

Events emitted by ToolAwareStream.

Content and reasoning deltas are yielded immediately as they arrive. Tool calls are accumulated internally and emitted as complete objects only once in the final StreamEvent::Done event.

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.

ContentDelta(String)

A fragment of text content from the assistant’s response.

ReasoningDelta(String)

A fragment of reasoning/chain-of-thought content.

ReasoningDetailsDelta(Vec<ReasoningDetail>)

Structured reasoning detail blocks (e.g., encrypted reasoning).

Done

The stream has finished. Contains all accumulated data.

tool_calls will be empty if the model did not invoke any tools. usage is typically only present in the final SSE chunk.

Fields

tool_calls: Vec<ToolCall>

Fully assembled tool calls (empty if none were requested).

finish_reason: Option<FinishReason>

The reason the model stopped generating.

usage: Option<ResponseUsage>

Token usage statistics (if provided by the API).

id: String

The response ID from the API.

model: String

The model that generated the response.

Error(OpenRouterError)

An error occurred while processing the stream.

Trait Implementations

impl Debug for StreamEvent

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

Formats the value using the given formatter.