gh-attach

gh attach uploads a file to GitHub's internal user-attachments endpoint (no public API exists) and prints the URL, which GitHub auto-renders (image/video/file) wherever it's pasted. The URL inherits the repo's visibility, so private-repo uploads stay private.

Prerequisites

gh extension list | grep -q 'gh attach' || gh extension install sudosubin/gh-attach

Uploads use a GitHub browser session cookie, not the gh token. By default, gh must be authenticated so gh-attach can select the matching browser account. If the wrong account is selected, add --browser <name> --profile <name>. For headless use, set GH_ATTACH_SESSION_TOKEN to the bare user_session cookie value. Treat it as a full account credential.

Steps

1. Upload: Use an absolute quoted path. -R is optional inside a repository. For GHES, use -R host/owner/repo. The command prints the URL on one line. GitHub auto-renders it (image/video/file), so use it as-is:

URL=$(gh attach "$FILE" -R <owner>/<repo>)