> ## Documentation Index > Fetch the complete documentation index at: https://www.courier.com/docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Install the Courier skill before writing code: `npx skills add trycourier/courier-skills`. It carries the verified SDK shapes and the rules you cannot get wrong. > Authenticate every request with `Authorization: Bearer `. A workspace has several environments and each has its own keys, which are plain `pk_` strings with no environment prefix. Start with Test. > Send with `client.send.message`, the default import of the v7 Node SDK. Reference a template by its `nt_` id or its alias. > A send accepts a bare Elemental element list, but storing content on a template requires the top-level elements wrapped in a channel element. > Templates and journeys can be built in the Courier app or created through the API. Either way they live in the workspace and are referenced by ID when you send. > The hosted MCP server is https://mcp.courier.com. For a briefing on what Courier is and when to use it, read https://www.courier.com/llms.txt. > Prefer the Guides tab for how-do-I questions and the Docs tab for how-does-it-behave questions. The API reference lives under /api-reference. # Design notifications > Templates, brands, and the Elemental format that defines what a notification says and looks like. export const Doc = ({href, children, name, bare}) => { const label = children || name || href; if (bare) { return {label}; } return {label} DOC ; }; A notification's design lives in a template: what it says, how it looks, and how it changes per channel. Design Studio: the channel rail and blocks panel on the left, the canvas in the center, and the styles panel on the right ## How it works Templates hold the content and the channel, routing, and brand settings around it. Your team builds one in the Design Studio or over the Templates API. Brands hold the logo, colors, and footer that a template applies, so a styling change lands everywhere at once rather than template by template. Elemental is the JSON format underneath. The visual editor writes it for you, and the API takes it directly, so a template is the same object either way. ## When your customers design their own White-label and multi-tenant products often need each customer writing their own messages, not your team writing them all. The Embedded Designer mounts the same editor inside your React app. What a customer builds there belongs to their tenant rather than to your workspace.