Enum StreamEvent 

pub enum StreamEvent {
    Text(String),
    Reasoning(ReasoningChunk),
    ToolCall(ToolCall),
    Status(String),
    Done {
        usage: Option<TokenUsage>,
        provider_continuation: Option<ProviderContinuation>,
        stop_reason: Option<FinishReason>,
    },
}

One event emitted during a streaming model call — the adapters’ own type, re-exported rather than redefined.

This was a second enum with the same five variants, and the only thing it added was a richer Done — which cost a translation layer that could only fill those extra fields with None, because the adapter-side Done it mapped from carried a bare token count. mermaid_model’s Done carries the whole terminal payload now, so there is nothing left for a second type to add. A single event emitted during a streaming model call.

Exactly one Done ends a successful stream. Text and Reasoning may interleave in any order. ToolCall events typically arrive at the end of generation but the contract is “before Done”.

Adapters themselves never emit Done — the provider wrapper builds the authoritative one from the returned ModelResponse, which is where the usage and the provider continuation actually live (F3).

Variants

Text(String)

Plain assistant content. Append to the response buffer.

Reasoning(ReasoningChunk)

Reasoning / thinking content. Render separately from regular text; renderer decides whether to display or hide based on user prefs.

ToolCall(ToolCall)

A tool/function call extracted from the model response.

Status(String)

Out-of-band, user-visible plumbing notice (e.g. “Starting the local Ollama server…”). NOT response content: surfaces as a transient / system line, never appended to the assistant message. May arrive before any Text.

Done

Stream complete. Carries final token usage (None when the provider never reported any, so the reducer keeps its estimate rather than resetting the gauge to zero), any opaque provider continuation state to round-trip on the next request, and why generation stopped (so the reducer can flag truncation or a content block).

Fields

usage: Option<TokenUsage>

provider_continuation: Option<ProviderContinuation>

stop_reason: Option<FinishReason>

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<(), Error>

Formats the value using the given formatter.