Copy check
The copy is read before it goes to a thousand people.
Every saved sequence is checked for the things that tend to put cold email in spam or cost it replies. Each one is a warning with the numbers, and none of them stops a campaign.
Spam words
A short list of words filters notice, such as free, guarantee, click here and 100%, named where they appear. The list is short on purpose, so ordinary sales words are not flagged and the warnings stay worth reading.
Links
More than two links in the body. Cold email with more is more likely to land in spam.
Capitals and exclamation marks
Three or more words in capitals, which reads as shouting, and an exclamation mark in the subject or two in the email.
Length
A subject over 60 characters, which gets cut off on most phones, and a body over 150 words.
Images
Any image in the body, which makes cold email look like marketing mail.
A way out
The unsubscribe header off and no {{unsubscribe}} link in the body, so people have no way to opt out.
Merge fields
Merge fields are taken out before the copy is judged, so {{FIRST_NAME}} is not shouting and a field that holds a link is not counted as one.
Where you see it
Under each email in the editor, variant by variant, with the flagged words and links marked in its lines, and a line above the steps that counts the warnings and names their steps. Checked on the saved sequence every time you save. And again when you launch, as a count of what is left to look at.