fix(server-utils): Instrument the Vercel AI experimental_decide channel event (#25068)

Since `ai` 7.0.128, `experimental_evaluate` calls produce no
`gen_ai.evaluate` span. The release renamed it to `experimental_decide`,
and the tracing channel now publishes `type: "experimental_decide"`. Our
subscriber only matched the old name. It now handles both, since 7.0.111
to 7.0.127 still publish `experimental_evaluate`.

This broke the evaluate integration tests and the `node-eve` Jev e2e
test on every PR, because the suite installs `ai@^7.0.111`.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: RulaKhaled

packages/server-utils/src/integrations/vercel-ai/vercel-ai-dc-subscriber.ts

@@ -217,7 +217,8 @@ export type ChannelEventType =
   | 'embed'
   | 'embedMany'
   | 'rerank'
-  | 'experimental_evaluate';
+  | 'experimental_evaluate'
+  | 'experimental_decide';
 
 /**
  * The context object the AI SDK passes through one tracing-channel call. It is the same object
@@ -451,7 +452,9 @@ export function createSpanFromMessage(
     }
     case 'rerank':
       return startGenAiSpan('rerank', modelId, baseAttributes);
+    // `ai` 7.0.128 renamed `experimental_evaluate` to `experimental_decide`; older 7.x still publishes the old name.
     case 'experimental_evaluate':
+    case 'experimental_decide':
       return startGenAiSpan('evaluate', modelId, {
         ...baseAttributes,
         ...(recordInputs
@@ -654,7 +657,7 @@ function getOutputMessages(
   result: Record<string, unknown>,
   finishReason: string | undefined,
 ): string | undefined {
-  if (type === 'experimental_evaluate') {
+  if (type === 'experimental_evaluate' || type === 'experimental_decide') {
     return stringify([{ type: 'evaluation', answers: withProviderConfidence(result) }]);
   }
   // `languageModelCall` exposes the response as a `content` parts array; top-level results expose

packages/server-utils/test/integrations/vercel-ai/evaluate.test.ts

@@ -0,0 +1,57 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+import { getMainCarrier, setCurrentClient, spanToStaticSpanJSON } from '@sentry/core';
+import type { Span } from '@sentry/core';
+import { createSpanFromMessage, enrichSpanOnEnd } from '../../../src/integrations/vercel-ai/vercel-ai-dc-subscriber';
+import { getDefaultTestClientOptions, TestClient } from '../../mocks/client';
+
+type Message = Parameters<typeof createSpanFromMessage>[0];
+
+describe('Vercel AI evaluate spans', () => {
+  let endedSpans: Span[];
+
+  beforeEach(() => {
+    getMainCarrier().__SENTRY__ = undefined;
+    const client = new TestClient(
+      getDefaultTestClientOptions({
+        dsn: 'https://public@dsn.ingest.sentry.io/1337',
+        tracesSampleRate: 1,
+      }),
+    );
+    setCurrentClient(client);
+    client.init();
+    endedSpans = [];
+    client.on('spanEnd', span => endedSpans.push(span));
+  });
+
+  afterEach(() => {
+    getMainCarrier().__SENTRY__ = undefined;
+  });
+
+  // `ai` 7.0.128 renamed the channel event from `experimental_evaluate` to `experimental_decide`.
+  it.each(['experimental_evaluate', 'experimental_decide'] as const)('creates an evaluate span for `%s`', type => {
+    const message = {
+      type,
+      event: {
+        provider: 'gateway',
+        modelId: 'typesafe-ai/jev',
+        state: 'I want a refund',
+        questions: { wantsRefund: { type: 'boolean', instructions: 'Is a refund requested?' } },
+        recordInputs: true,
+        recordOutputs: true,
+      },
+      result: { answers: { wantsRefund: { type: 'boolean', probability: 0.99 } } },
+    } as unknown as Message;
+
+    const span = createSpanFromMessage(message, {} as Parameters<typeof createSpanFromMessage>[1])!;
+    expect(span).toBeDefined();
+    enrichSpanOnEnd(span, message, {} as Parameters<typeof enrichSpanOnEnd>[2]);
+    span.end();
+
+    const json = spanToStaticSpanJSON(endedSpans[0]!);
+    expect(json.description).toBe('evaluate typesafe-ai/jev');
+    expect(json.op).toBe('gen_ai.evaluate');
+    expect(JSON.parse(json.data?.['gen_ai.output.messages'] as string)).toEqual([
+      { type: 'evaluation', answers: { wantsRefund: { type: 'boolean', probability: 0.99 } } },
+    ]);
+  });
+});