# Content screening (/docs/content-screening)

coss.com screens a sample of the messages your **live** environments send, right before they are
handed to the email provider or the carrier, for spam, phishing, malware and fraud. It protects the
people who receive them and the deliverability of every sender on coss.com. Sandbox messages are
never screened.

## Which messages are screened [#which-messages-are-screened]

Screening applies to live [emails](/docs/email/sending) (sub-accounts' and inboxes' included) and
live [SMS](/docs/sms/sending). Each organization is sampled on its own: every one of its first
messages, more as its volume grows, and after that a share of messages chosen at random. Which
messages are sampled is never announced and can't be predicted, so a sender can't save the abuse
for the messages it expects to be unscreened. A [sub-account](/docs/email/subaccounts) is sampled
on its own too, so its first messages are always screened.

## Verdicts [#verdicts]

An AI model scores the message for each category, and the highest score decides:

| Verdict   | What happens                                                                                                  |
| --------- | ------------------------------------------------------------------------------------------------------------- |
| Allowed   | The message is sent                                                                                           |
| Flagged   | The model thinks it may be abusive. It is sent, and your organization's [standing](/docs/reputation) becomes `warning` |
| Blocked   | The model is confident it is abusive. It isn't sent, and live sending is suspended                            |

A blocked email fails with `content_rejected` (an `email.failed` webhook); a blocked SMS fails the
same way (`sms.failed`). Live sending is then suspended for the whole organization (an
`account.suspended` webhook, an email to owners and admins) until coss.com support has reviewed
it, as for any [suspension](/docs/reputation#when-live-sending-is-suspended). When the blocked email
belongs to a sub-account, only that sub-account is paused (`subaccount.paused`, with
`data.trigger` `content_screening`), not your organization.

Flags expire with the reputation window: once no flagged message is left in it, the warning clears
by itself.

## When screening is unavailable [#when-screening-is-unavailable]

A message sampled for screening is never sent unscreened. If the model doesn't answer in time, the
message is held: it stays `queued`, and coss.com tries again a minute later, and again until it gets
a verdict. A message still not screened an hour after it was due fails with
`content_screening_unavailable`. Messages that weren't sampled are sent as usual.

## Privacy [#privacy]

- **What the model sees**: for an email, the sender address, the subject, up to 8,000 characters of
  its readable text and the host and path of its links (query strings removed); for an SMS, the
  sending number, the text and its links' hosts and paths. Never recipients' addresses or numbers,
  and never attachments.
- **Who processes it**: the model runs through Vercel's AI Gateway with zero data retention: the
  model providers may not keep the content or train on it.
- **What coss.com keeps**: the verdict, never the message's content. Verdicts are kept for
  90 days (see [data retention](/docs/data-retention)).
- **Scores stay internal**: the API, webhooks and dashboard show `content_rejected` and your
  standing, never a message's scores. Screening is not a spam checker you can test content against.

The model's instructions treat the message as untrusted data, but text written to manipulate it can
still lower its scores; screening is one safeguard among several (bounce, complaint and opt-out
rates, and coss.com's own review).

## If a decision is wrong [#if-a-decision-is-wrong]

Contact coss.com support: a person reviews every suspension, and reinstates the organization when
the message wasn't abusive. To have a person review an automated decision and explain your point of
view, write to [legal@cal.com](mailto:legal@cal.com). See the
[Acceptable Use Policy](/legal/acceptable-use#4-content-screening) and the
[Privacy Policy](/legal/privacy#4-automated-content-screening).