rawFinishReason

The provider's OWN finish-reason string, before mapping. The mapped finishReason collapses unknown values to FinishReason.Other — but for diagnosing a provider-side abort the raw string is the evidence; never discard it.

Populated by: Gemini (generateContent finishReason), Gemini Interactions (status), Anthropic (stop_reason), OpenAI Responses (incomplete_details.reason / error code), Cohere (from LanguageModelResult.rawFinishReason), Hugging Face Responses (incomplete_details.reason), Amazon Bedrock (stopReason), and ai.torad.aisdk.middleware.simulateStreamingMiddleware (propagated from the generate result). Null when the provider does not send a finish-reason string (e.g. KtorGatewayTransport,