Export Download Debugging

When your image export runs without errors but saves a 0 KB file, this skill walks Claude through the right debugging order. It separates payload capture from the save operation, which matters because browsers often create the empty file first, then fail silently during the write. The guidance covers showSaveFilePicker, blob URLs, data URL fallbacks, and Electron's download manager, with a focus on proof before escalation. It's tuned for web artifacts and preview iframes where sandboxing or CSP can break what looks like working code. If you've ever watched a user click Save As and get nothing, this gives Claude the evidence checklist and fix sequence to actually resolve it.

skills.sh installs: 1.9K
GitHub stars: 106.9K
last updated: Aug 21, 2026

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Install

$ npx -y skills add nexu-io/open-design --skill export-download-debugging --agent claude-code

Installs into .claude/skills of the current project.

Files

Export Download Debugging

Use this when an export or download appears to run but produces an empty, missing, or unusable file. It is tuned for browser previews, iframe capture, and Electron shells.

Core rule

Separate capture from save. Prove the export payload has non-zero bytes before debugging the destination path. A 0 KB file often means the native picker or host created the target file, then the write failed or was blocked.

Evidence

Record the payload type, MIME type, byte length, object URL or data URL path, and thrown error name/message.
Check browser console output and app logs around showSaveFilePicker, createWritable, <a download>, URL.createObjectURL, and URL revocation.
In Electron, inspect the will-download path: filename, MIME, file extension, save dialog filters, cancellation, and final file size.
Confirm the actual downloaded file size on disk and whether it opens in a normal image viewer.