A read-only prompt for the image you know you uploaded but cannot name. Since 1.7.4 the media search matches the filename and the alt text, not just the title, so half-remembered details are enough to find it.
Your agent reports it lacks permission to write alt text or a featured image. It does not. Both live under keys the custom-field abilities never reach, and two media abilities do the job.
The upload ability carries an alt parameter, so a new image can arrive with its description already written instead of joining the pile of blanks you fix months later.