Struct StreamFinal 

pub struct StreamFinal {
    pub kind: StreamFinalKind,
    pub usage: Usage,
    pub finish_reason: Option<FinishReason>,
    pub message_id: Option<String>,
    pub response_id: Option<String>,
    pub provider_request_id: Option<String>,
    pub provider: String,
    pub model: Option<String>,
    pub raw: Value,
}

The provider’s terminal stream record, normalized.

This replaces the provider-typed final payload that streams used to carry: usage is a plain field rather than a trait method, and the finish reason is normalized exactly as on the unary CompletionResponse.

Providers that want their own terminal type keep it behind RawStreamingResult and map it once with normalize_stream.

Emission contract

A terminal record is emitted only when the provider signaled genuine completion — its own end-of-response event (an Anthropic message_delta with a stop reason, an OpenAI [DONE] / response.completed, a Gemini chunk carrying finishReason, and so on). Three failure shapes reach a consumer, and they are distinct:

Shape	Err item	Stream continues	Terminal record
Transport error (connection lost, HTTP failure)	yes	no	never
Malformed frame (recoverable parse error)	yes	yes	if a genuine terminal later arrives
Truncation (EOF without the provider’s end event)	no	—	never

On a terminal error (a transport failure or the provider’s own failure event), tool calls that were fully delivered before the failure are yielded before the terminal Err; nothing follows the error — the stream then ends without a terminal record.

Consequently an Err item is not by itself terminal: a malformed frame is surfaced and the stream keeps consuming, so a later genuine terminal still completes it. Consumers must drain the stream to None rather than stop at the first Err, and must treat the absence of a terminal record as truncation, never as a successful zero-usage completion.

Fields

kind: StreamFinalKind

Discriminating field; always StreamFinalKind::Final.

usage: Usage

Token usage reported by the provider for this streamed completion. Zero-valued usage is the documented sentinel for missing metrics.

finish_reason: Option<FinishReason>

Why the model stopped generating, when the provider reported it.

normalize_stream applies FinishReason::reconcile_with_output to this value using the tool calls actually seen on the stream, so a provider mapper does not need to (and cannot — it has no view of the preceding events).

message_id: Option<String>

Provider-assigned assistant message ID, when available — only IDs the provider would recognize on a replayed assistant message. Response-scoped identifiers belong in StreamFinal::response_id.

response_id: Option<String>

Provider-assigned response-scoped ID, when available — e.g. an OpenAI chat chatcmpl- ID. Never replayed to a provider as a message ID.

provider_request_id: Option<String>

The provider’s transport-level request identifier, taken from the SSE connection’s HTTP response headers (Anthropic request-id, OpenAI/xAI x-request-id). When the source reconnected, this is the connection that delivered this terminal record. Never the body’s message/response id. None means the provider did not report one — a documented outcome, never an error.

provider: String

Stable descriptor name of the provider that produced this stream.

model: Option<String>

Provider-reported model identifier, when available.

raw: Value

The provider’s own terminal record for this stream: the value the model’s inherent raw_stream would have yielded as its FinalResponse, serialized. It is the terminal record as rig’s wire type parsed it — fields that type does not model are not here — and it is the terminal record only, not the stream’s frames; see the module docs for why frames are a separate mechanism. normalize_stream populates it unconditionally — the same parity the pre-normalization Final(R) had.

An escape hatch for provider-specific data rig does not normalize — it never replaces a normalized field, and every normalized field means the same thing whatever this holds. Value::Null means the record was built without a provider behind it — StreamFinal::new without with_raw (a provider’s mapper before normalize_stream attaches the terminal, test doubles, hand-built records), or a record persisted before the field existed — never that the provider sent nothing: no stream that reached its terminal yields Null here.

Typed access is recoverable: provider terminal types are Deserialize, so provider::StreamingCompletionResponse::deserialize(&raw) returns the provider’s own type.

Implementations

impl StreamFinal

pub fn new(provider: impl Into<String>, usage: Usage) -> StreamFinal

Create a terminal record for provider with usage; optional metadata starts unset and is filled in with the with_* helpers.

pub fn with_finish_reason(self, finish_reason: FinishReason) -> StreamFinal

Attach the normalized finish reason.

pub fn with_optional_finish_reason( self, finish_reason: Option<FinishReason>, ) -> StreamFinal

Attach the normalized finish reason when the provider reported one.

pub fn identity(&self) -> ResponseIdentity

This terminal record’s identity metadata as one crate::completion::ResponseIdentity carrier.

impl StreamFinal

pub fn with_message_id(self, message_id: impl Into<String>) -> StreamFinal

Attach the provider-assigned message ID.

An empty string is treated as absent: gateways that echo "" for fields they don’t populate must not produce a Some("") that differs between the buffered and streaming paths. All identifier and model setters share this rule so the invariant lives here rather than at every provider call site.

pub fn with_optional_message_id( self, message_id: Option<impl Into<String>>, ) -> StreamFinal

Attach the provider-assigned message ID when the provider reported one.

pub fn with_response_id(self, response_id: impl Into<String>) -> StreamFinal

Attach the provider-assigned response-scoped ID.

pub fn with_optional_response_id( self, response_id: Option<impl Into<String>>, ) -> StreamFinal

Attach the provider-assigned response-scoped ID when the provider reported one.

pub fn with_provider_request_id( self, request_id: impl Into<String>, ) -> StreamFinal

Attach the provider’s transport-level request identifier.

pub fn with_optional_provider_request_id( self, request_id: Option<impl Into<String>>, ) -> StreamFinal

Attach the provider’s transport-level request identifier when the provider reported one.

pub fn with_model(self, model: impl Into<String>) -> StreamFinal

Attach the provider-reported model identifier.

An empty string is treated as absent, matching the identifier setters.

pub fn with_optional_model( self, model: Option<impl Into<String>>, ) -> StreamFinal

Attach the provider-reported model identifier when the response carried one.

pub fn with_raw(self, raw: impl Into<Value>) -> StreamFinal

Attach the provider’s own response, serialized — the value the model’s inherent raw method would have returned. Every provider seam calls this; see the raw field for the exact meaning of the payload (and of Value::Null).

Trait Implementations

impl Clone for StreamFinal

fn clone(&self) -> StreamFinal

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StreamFinal

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for StreamFinal

fn deserialize<__D>( __deserializer: __D, ) -> Result<StreamFinal, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<(&str, CopilotStreamingResponse)> for StreamFinal

fn from(_: (&str, CopilotStreamingResponse)) -> StreamFinal

Converts to this type from the input type.

impl From<(&str, StreamingCompletionResponse)> for StreamFinal

Normalize an Anthropic terminal stream record.

The provider descriptor name is an input rather than a constant: the Anthropic Messages stream format is shared by every Anthropic-compatible provider, so baking in "anthropic" here would mislabel all of them.

fn from(_: (&str, StreamingCompletionResponse)) -> StreamFinal

Converts to this type from the input type.

impl From<(&str, StreamingCompletionResponse)> for StreamFinal

Normalize the Responses API’s terminal stream record.

The provider descriptor name is an input for the same reason it is on the unary conversion: ChatGPT and Copilot stream this exact wire shape, so a baked-in "openai" would mislabel them.

The finish reason is left exactly as the provider reported it; crate::streaming::normalize_stream applies the tool-call reconciliation afterwards, using the calls the stream actually emitted.

fn from(_: (&str, StreamingCompletionResponse)) -> StreamFinal

Converts to this type from the input type.

impl<U> From<(&str, StreamingCompletionResponse<U>)> for StreamFinal

where U: Into<Usage>,

Normalize an OpenAI-compatible streaming terminal record.

As on the unary path, the provider descriptor name is an input rather than a constant: this terminal record is shared by every OpenAI-compatible provider, so baking in "openai" here would mislabel Groq, Together, DeepSeek and the rest.

fn from(_: (&str, StreamingCompletionResponse<U>)) -> StreamFinal

Converts to this type from the input type.

impl From<StreamFinalRepr> for StreamFinal

fn from(repr: StreamFinalRepr) -> StreamFinal

Converts to this type from the input type.

impl From<StreamingCompletionResponse> for StreamFinal

fn from(response: StreamingCompletionResponse) -> StreamFinal

Converts to this type from the input type.

impl From<StreamingCompletionResponse> for StreamFinal

fn from(response: StreamingCompletionResponse) -> StreamFinal

Converts to this type from the input type.

impl PartialEq for StreamFinal

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for StreamFinal

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for StreamFinal