Claude is told to upload files instead of storing them in artifact documents

When Claude saves a document to an artifact's storage and the write is too big or over its limit, Claude Code checks for what looks like base64 data. Base64 is a way of writing a file out as text. If it finds some, the error now tells Claude that documents hold data, not files, and to upload the file with upload_asset. The message also gives the maximum document size in KiB. Before, the error only gave the size and said to write less per document.