Artifacts not generated as shown in Codelab

I am following the official Google Antigravity Codelab, specifically Section 7 — Artifacts.

When I use the Codelab prompt:

Design a Node application that I can run from the command line to get me the latest news from Google.

the Codelab shows Antigravity creating artifacts such as an Implementation Plan and Walkthrough.

However, with my setup, the agent starts working immediately and does not generate the expected artifacts or show them in the Auxiliary Pane.

Environment

• Antigravity: 2.19.1
• Model: Gemini 3.8 Flash Low
• Codelab: Getting Started with Google Antigravity
• Section: 7 — Artifacts

Steps to reproduce

1. Open Antigravity 2.19.1.
2. Create or open a workspace.
3. Select Gemini 3.8 Flash Low.
4. Send the prompt from the Codelab.
5. Observe the agent's response and artifacts.

Expected

An Implementation Plan artifact should be generated before implementation, followed by a Walkthrough artifact after the work is completed, as demonstrated in the Codelab.

Actual

No artifacts are generated or displayed.

Question

Is this a known issue or an expected limitation of Gemini 3.8 Flash Low or Antigravity 2.19.1?

Codelab: https://codelabs.developers.google.com/getting-started-google-antigravity?hl=en#6