# Modules and elements

> Emails are built from modules (sections) containing rows, columns and elements. How they're addressed, and why ids come in pairs.

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

A Stensul email is a stack of **modules**: a header, an opening section, a two-column feature block, a footer. Admins design modules in Stensul Studio, publish them, and add them to libraries. Marketers, and assistants, assemble emails from them.

```text
email
└── module (a section, e.g. "the opening section")
    └── row
        └── column
            └── element: text | button | image | divider | custom | …
```

## What an assistant can change

| Element | Editable through the MCP |
| --- | --- |
| Text | Copy, links, headings and lists, within the module's rules |
| Button | Label, destination URL, per-link tracking |
| Image | Source (upload or gallery), alt text, destination link |
| Divider | Style and visibility only, where allowed |
| Custom element | Named **variables** only. Their markup is never returned and never writable |
| Any element with a `visibility` field | Show or hide it |

## Addressing: always a pair

In a read (`stensul-read-email`, view `plan`), every element carries its own module id. Elements of the same type in **different** modules can share a numeric id, so updates always name the module id **and** the element id. When building from a template, `stensul-build-email` uses **positions** instead, so there are no fresh ids to juggle.

## Removing things

- **Hide** an element that has a `visibility` field. Nothing is lost.
- **Delete a module** with `stensul-delete-email-module` when a whole section should go.
- An element with no `visibility` field can only go by deleting its module. If the module holds other content, the tool lists what would be lost and waits for the person to agree.

## When admins update a module

Admins can publish module updates as **mandatory** or **optional**. A draft with an outdated mandatory module can't be completed until it's updated, and a draft that uses a module an admin removed from the library can't be completed until that module is swapped out. Your assistant's draft follows the same rules as any other.