---
id: FR-3
title: Adding MCP servers
group: On this device
summary: Connecting a streamline to your own MCP servers, and how signing in to them works
keywords: [mcp, server, url, oauth, sign in, tools, connect, endpoint]
---

An MCP server is what gives a streamline its tools: a service that offers actions such as *look up an order* or *add a note*, which the assistant can call. A streamline can use several.

## Adding one

In the streamline editor, under **MCP servers**, choose **Add** under **Servers** and fill in:

- **Name** (optional): how the server is named in sign-in cards and in the Vault. Without one, its address's host is used.
- **URL**: the server's address, starting `https://`, as its maker gives it to you.
- **Auth**: **oauth** for servers that have you sign in through their own page, or **none** for servers that need no sign-in. The editor offers only these two; **password** and **api-key** sign-in come later (a file that already names one keeps it).
- **Tools**: the server's tool rules. See Tool rules (FR-4).

Save the streamline. A server with no address is marked under the field, and the streamline can't be saved until you fill it in or remove it.

## Signing in

You do not sign in when you add a server. The first time the assistant calls it and the server asks who you are, a sign-in card appears in the chat: *Sign in to* the server's name. Sign in on the server's page, and the call goes through. See Sign-in cards (AS-4).

The session is kept in this device's Keychain and never syncs; the Vault lists it under **Sign-ins**. Some servers end sessions after a while; you are asked to sign in again when that happens.

## What the server sends back

Results are drawn as cards. If a server sends a plain answer, the app draws it as a simple card on its own. A streamline can carry its own **Card designs**, and **Renderers** on a server say which tool uses which. Open a design in the Library to see it drawn with sample data. If a design cannot be read, that tool falls back to the simple card.

## What to watch for

Every tool on a server is available to the assistant unless you hide it. Tools the server marks as read-only run straight away; everything else waits for your tap. To change that, see Tool rules (FR-4).