Write Amazon's contains-synthetic-performer tag with exiftool

To tag an image or video for Amazon, write the keyword contains-synthetic-performer into the XMP dc:subject field of the file with an IPTC-compatible metadata editor such as exiftool. Sume does not write this keyword for you: the Sume docs do not mention C2PA, IPTC or XMP embedding at all. So the flow is render with Sume, download the file, tag it yourself, then upload it to Amazon.

What Amazon says

The facts below come from a seller forum announcement. The thread also shows unanswered seller questions (scope for Brand Story, Store and ad videos, whether it is retroactive, how it is verified), so treat the edges as open.

Where Sume fits

Sume produces the media. The Image API returns generated images, and Timeline 1.0 assembles clips into one MP4. Neither doc says it embeds IPTC or XMP keywords, so assume the file arrives without your keyword and add it as the last step before upload.

Order matters. Tag after your final render. Any later re-encode or crop is a new file, and a re-encode may not carry the field forward, so read the tag back from the exact file you upload.

Tag a downloaded file

exiftool appends a value to the XMP subject list with the += form. Run it on a copy, then read the field back to confirm. Whether a given container keeps XMP is something to check on your own file, not something this post can promise.

# append the keyword to dc:subject
exiftool -XMP-dc:Subject+="contains-synthetic-performer" hero-1.png

# confirm it is there
exiftool -XMP-dc:Subject hero-1.png

# same for an MP4 (check the read-back prints the keyword)
exiftool -XMP-dc:Subject+="contains-synthetic-performer" spot-1.mp4
exiftool -XMP-dc:Subject spot-1.mp4

Checklist

• Sort the library first: only photorealistic AI people need the tag (see the exempt-cases post).
• Tag the final file, not a draft, and keep the untagged original.
• Read the field back before uploading.
• Do not tell a client that Sume tags files. It does not.
• Re-check the Amazon thread before a launch, since the open questions there may get answers.