Privacy & Image Filtering
Pearl Bot is a moderation and utility bot for Nerimity. This page explains the automatic image filter, which is part of the bot on every server it joins.
Automatic image filter
Pearl Bot checks image and GIF attachments posted in server channels for nudity and other sexual or abusive content. The filter is always on for every server and cannot be switched off by server admins. Direct messages are not scanned. Videos and other file types are not scanned.
How it works
- When a message with an image or GIF attachment is posted, the bot downloads the file and calculates a fingerprint (a SHA-256 hash) so identical images don't have to be checked again.
- The image is checked by a third-party moderation service. Depending on how the bot owner has configured the filter, this is either modops.ai (it receives the link to the image on Nerimity's CDN) or OpenAI's moderation API (it receives the image file itself). The service returns a score for each category. For GIFs only the first frame is typically evaluated. Pearl Bot does not send the message text or usernames to these services.
- If the score for a category is above the bot's threshold, the whole message is deleted and the author gets a short notice in the channel.
- If the service is unavailable, the limit is reached, or an error occurs, the image is let through unchecked.
What is stored
- Hashes of checked images (no picture, just a fingerprint) with a result: clean results are kept for 30 days; images confirmed by the bot owner as safe or NSFW are kept so they are handled instantly next time.
- Reports of flagged images: the author's Nerimity ID and username, server name and ID, channel, message ID and text, time, the categories detected, and — for ordinary reports — a copy of the image. The copy is visible only to the bot owner, is wiped 7 days after a decision (or after 30 days at most) and is shown blurred by default.
- For the most serious categories (child-safety related), no copy of the image is ever stored. Only the report details above are kept. The bot owner can also turn off storing image copies completely.
Who can see it
Only the bot owner reviews reports and marks them as safe or NSFW. Reports are not shared with server admins. Content that appears to be illegal may be reported to the competent authorities.
Mistakes
Automatic filters make mistakes. If your image was removed by error, contact Pearl Bot support on Nerimity and mention the server and the approximate time, so the report can be found and corrected.
Third-party service
Images are processed by modops.ai or OpenAI (whichever is active) under their own terms and privacy policies. Nerimity itself is a separate service with its own policies.