Can't get past /design-sync authorization in any environment I tried

Hey team — I ran into a wall today trying to use /design-sync and wanted to flag it in case it's a real gap rather than something I'm doing wrong.

Here's the situation: I already have a design system set up in Claude Design (created by uploading a Figma export). I built out a small coded component library locally and wanted to push it into that same Claude Design project using /design-sync, so the design agent could start building with the real components instead of placeholders.

Every time I tried, I got this: "DesignSync needs design-system authorization, but /design-login requires an interactive terminal and is not available in this environment."

Fair enough, I thought — so I tried to find an actual interactive terminal:

1. First I was in the Claude desktop app — got the error above.
2. The error suggested using "Send to Claude Code Web" from the Claude Design project, so I tried that — got the exact same error, in what's supposedly a different kind of session.
3. Then I opened an honest-to-goodness Terminal window and ran the Claude Code CLI directly (the real interactive terminal the error message says should work) — and this time the DesignSync tool wasn't even available at all. /design-login just said "Unknown command."

So across three different environments — desktop app, "Claude Code Web," and a plain terminal — I never got past this. It seems like whatever's supposed to unlock this authorization step isn't working anywhere right now, or the tool isn't consistently available depending on how you're running Claude Code.

Would love for this to get fixed, since /design-sync is exactly the workflow I need to keep my design system's code and my Claude Design project in sync going forward.

Environment: Claude desktop app (macOS), Claude Code CLI v2.1.140