# Security and data

> How the Stensul MCP server controls access, what it can and can't do in your account, and where to get Stensul's security documentation.

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

This page covers how access works, as the product behaves today. For data handling, model training, retention, sub-processors and certifications, use Stensul's security documentation (below) rather than this page.

## How access is controlled

- **Every call acts as a signed-in person.** The MCP server uses the OAuth authorization-code flow. There is no API-key or client-credentials path for MCP. See [Authentication](https://stensul.com/developers/authentication/).
- **Two checks on every request.** The connection's scopes and the person's own Stensul permissions both have to allow the action. The MCP can't do anything the person couldn't do in the Stensul app.
- **Scopes are hard limits.** A connection without `emails:write` can't create or edit emails, however it's prompted.
- **Guardrails are enforced by Stensul.** Locked content, palettes, fonts and character limits are checked by Stensul on every change. A change that breaks one is declined and reported; it is not reshaped or retried.
- **Drafts, not sends.** The MCP creates and edits drafts. It doesn't send email, schedule it, upload it to an ESP, or route it for approval.
- **Deletes need the person's request.** The only delete tool removes a module from a draft, and it asks for confirmation when more would be lost than the person named.
- **Scope changes take effect on issued tokens.** Adding a scope to a connection revokes its existing tokens, so everyone signs in again.

## Security documentation

- [Stensul Security and Trust Center](https://stensul.com/security-trust-center)
- Customers can ask their Stensul contact for the MCP security and data access FAQ.

## Terms

Use of the Stensul MCP server is covered by Stensul's [product-specific terms](https://assets.stensul.com/corp/terms/stensul-product-terms-2026-07.pdf).