earendil-works/pi · error

Mistral stream ended without a finish reason

Error message

Mistral stream ended without a finish reason

What it means

Error "Mistral stream ended without a finish reason" thrown in earendil-works/pi.

Source

Thrown at packages/ai/src/api/mistral-conversations.ts:155

			const normalizeMistralToolCallId = createMistralToolCallIdNormalizer();
			const transformedMessages = transformMessages(context.messages, model, (id) => normalizeMistralToolCallId(id));

			let payload = buildChatPayload(model, context, transformedMessages, options);
			const nextPayload = await options?.onPayload?.(payload, model);
			if (nextPayload !== undefined) {
				payload = nextPayload as MistralChatPayload;
			}
			const mistralStream = await requestMistralStream(model, payload, apiKey, options);
			stream.push({ type: "start", partial: output });
			await consumeChatStream(model, output, stream, mistralStream);

			if (options?.signal?.aborted) {
				throw new Error("Request was aborted");
			}

			if (output.stopReason === "pending") {
				throw new Error("Mistral stream ended without a finish reason");
			}
			if (output.stopReason === "aborted" || output.stopReason === "error") {
				throw new Error(output.errorMessage || "An unknown error occurred");
			}

			stream.push({ type: "done", reason: output.stopReason, message: output });
			stream.end();
		} catch (error) {
			for (const block of output.content) {
				// partialArgs is only a streaming scratch buffer; never persist it.
				delete (block as { partialArgs?: string }).partialArgs;
			}
			output.stopReason = options?.signal?.aborted ? "aborted" : "error";
			output.errorMessage = formatMistralError(error);
			stream.push({ type: "error", reason: output.stopReason, error: output });
			stream.end();
		}
	})();

View on GitHub (pinned to 4af9d21d3b)

Solutions

1. Retry; check for stream truncation before a finish reason arrived.

When it happens

Trigger: Thrown at packages/ai/src/api/mistral-conversations.ts:155 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of earendil-works/pi@4af9d21d3b (2026-08-24). Data as JSON: /api/errors/a619a63352a58d9f. Report an issue: GitHub.