Claude Code can't read the artboards of a Claude Design canvas artifact

Problem

When a Claude Design canvas artifact is attached to a Claude Code session (via /artifacts), Claude cannot read the canvas's actual designs, so it can't build code from them.

What was tried

1. Artifact tool, action: read on the canvas URL returns only the Design type's runtime shell (index.html that loads artifact-type/app.js). The README in that page says the canvas content lives in files under project/ (project/canvas.json and one project/<path>.dc.html per artboard), but the read action exposes no way to fetch them. Passing a path inside the artifact URL is rejected: "url names a path inside the artifact — pass the artifact's own URL".
2. Artifact tool, action: read_db on the canvas returns nothing (collection project is empty).
3. DesignSync tool (after /design-login and /design consent) list_projects only returns design-system-type projects. The canvas isn't listed, so list_files / get_file can't reach it.

Expected

Claude can read a canvas's project/canvas.json and its .dc.html artboards, e.g. via an Artifact read option for files inside the artifact, or DesignSync access to canvas projects.

Use case

Design mobile screens in a Claude Design canvas, then ask Claude Code to build the matching Flutter widgets from them. Right now the only workaround is manually exporting artboards into the repo.

🤖 Generated with Claude Code