Bug Report: TypeError: metadata.suggestions is not iterable

[jackkru69]

Environment:

• Official chat.vercel.ai UI template
• Inference model: o3-mini

Description:
The suggestions panel attempts to iterate over metadata.suggestions without verifying that it’s an array. When metadata.suggestions is undefined or non‑iterable, a runtime error halts rendering.

Steps to Reproduce:

1. Run the official chat.vercel.ai UI template with the o3‑mini model.
2. Invoke the suggestions component (e.g., the backend returns no suggestions field or returns it as null).
3. Open the browser’s Developer Console.

Actual Behavior:

Uncaught (in promise) TypeError: metadata.suggestions is not iterable
    at eval (client.tsx:38:25)
    at Artifact.onStreamPart (client.tsx:34:7)
    at DataStreamHandler.useEffect (data-stream-handler.tsx:41:28)
    …

The suggestions UI never appears, and errors flood the console.

Expected Behavior:
The panel should safely handle missing or non‑array metadata.suggestions and render (or remain empty) without errors.