# Segment Sets

> Admin-defined audience versions you can apply to a section of an email, then write copy for each audience. What works through the MCP today.

Source: https://stensul.com/developers/concepts/segment-sets/ · Last reviewed 2026-09-28

A **Segment Set** is a named, ordered list of audience segments (for example "Gold", "Silver", "Everyone else") that an admin builds once in Stensul. Applying it to a section of an email creates one version of that section per segment. Your ESP decides at send time which version each subscriber sees.

```text
                 ┌─ Gold ───────── "Free shipping on the Autumn blend"
opening section ─┼─ Silver ─────── "15% off the Autumn blend"
                 └─ Everyone else ─ "Meet the Autumn blend"
```

## Through the MCP

1. Check the library supports it: `dca_segment_sets.supported` in `stensul-get-libraries`.
2. List the sets: `stensul-list-segment-sets`.
3. Apply one to a module and write every segment's copy in the same call: `stensul-apply-segment-set` with `segments`.
4. Change one segment later: `stensul-update-segment-content`.

## What to know

- **You choose the set and write the versions. You can't change the set.** Audiences, their order and their conditions are admin-owned.
- **Scripted DCA libraries today.** Other dynamic-content setups aren't supported through the MCP yet.
- **Section level, text and buttons.** Personalizing images and dividers, or single elements, isn't available through the MCP yet.
- **The in-chat preview shows the base modules**, not each segment. Switch between versions in Stensul's own preview.
- Segment Sets are enabled per account. Ask your Stensul contact if you don't see any.