Root cause: Artifact file URL is constructed as file://wsl.localhost/c%3A/Users/... which is invalid. The artifact directory is on the Windows native filesystem (C:\Users\...), but the app prepends the WSL authority from the workspace path, creating an unreachable hybrid URL.
Expected: Artifact URLs for Windows-native paths should use file:///C:/Users/... regardless of workspace location.
Create a dummy folder on Windows filesystem, eg. C:\dummy
Remove all WSL2 folders from your AG2 project.
Add the dummy folder AS FIRST
Add all other (WSL2) folders
From now on artifacts will be displayed correctly, as AG2 constructs windows path for accessing them, for example:
file:///c%3A/Users/usera/.gemini/antigravity/brain/web32d34-d61f-wsde9-baad-1f87448f0848/walkthrough.md
The nice thing is that this works for past conversations as well!