chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/ai/test/mistral-raw-stop-reason.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+import { stream as streamMistral } from "../src/api/mistral-conversations.ts";
+import { getModel } from "../src/compat.ts";
+import type { Context, FetchFunction } from "../src/types.ts";
+
+const model = getModel("mistral", "devstral-medium-latest");
+const context: Context = {
+	messages: [{ role: "user", content: "hello", timestamp: Date.now() }],
+};
+
+function createFetch(finishReason: string): FetchFunction {
+	return async () =>
+		new Response(
+			`data: ${JSON.stringify({
+				id: "mistral-response-id",
+				model: model.id,
+				choices: [
+					{
+						index: 0,
+						finish_reason: finishReason,
+						delta: {},
+					},
+				],
+				usage: {
+					prompt_tokens: 1,
+					completion_tokens: 0,
+					total_tokens: 1,
+				},
+			})}\n\ndata: [DONE]\n\n`,
+			{ headers: { "content-type": "text/event-stream" } },
+		);
+}
+
+describe("Mistral raw stop reasons", () => {
+	it("preserves raw Mistral finish reasons for successful stops", async () => {
+		const message = await streamMistral(model, context, { apiKey: "test", fetch: createFetch("stop") }).result();
+
+		expect(message.stopReason).toBe("stop");
+		expect(message.rawStopReason).toBe("stop");
+		expect(message.errorMessage).toBeUndefined();
+	});
+
+	it("preserves raw Mistral finish reasons for provider error stops", async () => {
+		const message = await streamMistral(model, context, { apiKey: "test", fetch: createFetch("error") }).result();
+
+		expect(message.stopReason).toBe("error");
+		expect(message.rawStopReason).toBe("error");
+		expect(message.errorMessage).toBe("Provider stopped with: error");
+	});
+
+	it("treats unknown Mistral finish reasons as provider error stops", async () => {
+		const message = await streamMistral(model, context, {
+			apiKey: "test",
+			fetch: createFetch("unmapped_error"),
+		}).result();
+
+		expect(message.stopReason).toBe("error");
+		expect(message.rawStopReason).toBe("unmapped_error");
+		expect(message.errorMessage).toBe("Provider stopped with: unmapped_error");
+	});
+});