What does the Agent Ready check tell you before you send?

Before some of your readers open your newsletter, an AI has already read it. Gmail and Apple Mail now write a short summary of an email, and that summary can take the place of your preview text. Assistants and text-only email apps read it too. They work from the message itself, so they weigh your subject line and the first few lines of text, and they can’t read what an image says.

The Agent Ready check helps your newsletter arrive primed for those readers: easy to open, and easy to skim in a sentence or two. You’ll find it as the Agent Ready row in the Content Check panel (on the newer schedule screen, under Checked For You) when you click Preview and schedule, next to Accessible, Deliverable and Readable. If nothing needs a look, it shows a green check mark. If something does, it shows how many issues there are, with a warning sign.

What Letterhead sends with your newsletter

A newsletter sent through Letterhead or through Iterable goes out with two versions inside it: the designed version your readers see, and a plain-text version built from it. Text-only email apps show the plain-text version, and some inbox AI summaries read it.

Letterhead builds the plain-text version from the same newsletter, so you don’t write or maintain a second copy. It:

• turns your headings and paragraphs into readable lines of text;
• writes each link out next to its words, so the address isn’t lost;
• leaves out anything a reader never sees, including your preview text, which the inbox already shows on its own;
• leaves out the mobile-only copy of a block you’ve shown differently on desktop and mobile, since the desktop version is already in the text.

The plain-text version is a separate part of the message. It adds nothing to the designed version, so it doesn’t count toward the size at which Gmail clips a long email.

Newsletters sent through other providers go out without the plain-text version.

Reading the results

Click the arrow next to the row to open it. You’ll see:

• Subject line: your subject, shown for context. It’s never flagged, because every newsletter has one.
• The first words a summary sees: the opening of your newsletter, taken from the plain-text version, up to about 150 characters, with the written-out link addresses removed.
• Plain-text version: its size, and the full text, so you can read your newsletter the way a text-only app or an inbox AI does.

If your newsletter has more than one version for different readers, the row follows the Preview as choice in the composer, so you can read the version a particular group receives.

What the check flags

An opening with very little text

A summary starts from the first lines of your newsletter. If the start has very little text, because it opens with a large image or a row of buttons, there’s nothing for a summary to state the point from.

What to do: put your main point in the first sentence or two, as live text.

Hidden text a summary could still read

Some blocks are hidden from people but still sit in the message. A summary can read them, even though no reader ever sees them. The check lists how many blocks of hidden text it found and shows how the first one starts. Your preview text isn’t counted, and neither is the mobile-only copy of a block.

What to do: if the hidden text isn’t something you want read, remove it from the block’s HTML.

What it doesn’t check

• Images that need a description. An image with no alt text is reported in the Accessible row, so the same problem isn’t counted in two places. Adding alt text helps a summary too.
• Whether your subject line is good. The subject is shown, not scored.

It advises, it never blocks

The Agent Ready check is a heads-up, not a gate. A finding won’t stop you from scheduling or sending. The reading reflects your saved draft, so after you fix something, save, and it updates.

For readers who use a screen reader, see What does the Accessibility check flag before you send?. For whether your links work, see What does the Links check flag before you send?.