Connect AI tools

Connect Claude, ChatGPT, Cursor or another AI tool to your site, and ask it to build pages, write posts or fix your SEO from the app you already use. It signs in as you, can do only what you can, and every change it makes is in the audit log.

These tools connect through MCP, the Model Context Protocol: an open standard for letting AI tools use other software. Every Lettern site is an MCP server: it comes with Lettern, on from the start.

#Connect your AI tool

#1. Copy your server URL

Click your name at the bottom of the sidebar and choose Account. Under API & Agents, press Copy next to the MCP Server URL. It's your site's address followed by /mcp:

https://your-site.com/mcp

You can also press ⌘K and choose Connect an AI Agent (MCP) to go straight there.

#2. Add it to your tool

{
  "mcpServers": {
    "my-site": { "url": "https://your-site.com/mcp" }
  }
}

claude mcp add --transport http cms https://your-site.com/mcp

#3. Approve the connection

Your tool opens a page on your site. Sign in if you aren't already (with your two-factor code, if you use one). The page asks whether to connect the tool and shows what it will be able to do:

• Full Access: everything you can do in the admin.
• Read Only: it can look, but never change anything.

Press Connect, and you're back in your tool, connected. Your account needs access to the admin to connect a tool.

#Try it

Ask your tool for something real, for example:

Lettern tells it to read your collections and design system first, so what it builds uses your fonts, colors and components. Most tools also list your site's skills as ready-made prompts: Build a Page, Write a Blog Post, Audit the Site, Proofread and Adjust the Design.

#See and revoke connections

Every connected tool is listed under Tokens, in API & Agents on your Account screen, named after the tool, such as MCP: Claude, with when it was last used. Choose Revoke in its menu to disconnect it at once.

A connection stays signed in while you use it. One that goes unused for 180 days has to connect again.

#Use a token instead

For a tool that can't sign in with OAuth, create a token and send it with every request.

1. On your Account screen, under API & Agents, press New Token.
2. Give it a name, choose its Access (Full Access, Read Only or Content Only) and when it Expires, such as 30 Days or 1 Year, then press Create Token.
3. Copy the token: it's shown only once. Your tool sends it as a header:

Authorization: Bearer cms_…

A token acts as you. See REST API for scopes.

#What agents get

Tools: every ability you may run that is exposed to MCP, named with a dot (entries.create, design.update). Security-sensitive abilities, like creating tokens, changing passwords, managing users and roles, or changing what a role may do, are never offered to agents.

Resources: context to plan with. cms://collections (content types and their fields), cms://site/design (the design system: tokens, fonts, element styles), cms://blocks (how to compose pages, templates and components: the block model, styles, bindings, interactions and animations, with worked examples), cms://forms, cms://navigation, cms://languages, and more from plugins.

Prompts: the site's skills, ready-made workflows like Build a page from a brief, Write a blog post and Audit the site for SEO and GEO problems, plus whatever plugins add.

Instructions: how to build the Lettern way. Read the collections and the design system first, reuse components and templates (patterns/list, templates/list), style with tokens, give images alt text, and publish when done.

#For developers

#Building with agents

The editor works with structured data, so an agent edits the same block documents as the admin:

• Pages: entries/create and entries/update with a blocks field, as JSON or as Block Markdown.
• Templates and components: the same abilities, in the templates and components collections. entries/publish makes them live.
• The design system: design/get, design/update, design/fonts-import, and custom code with design/code.
• What's possible: blocks/types lists every block, style property, state, data source, animation property and script action. blocks/icons searches icons.

#Protocol

The server is at POST /mcp. It speaks the current stateless revision of MCP (2026-07-28: a version per request, server/discover) and answers older clients that send initialize (2025-11-25, 2025-06-18, 2025-03-26). Tool names are ability names with a dot instead of the slash.

OAuth follows the MCP authorization spec: protected resource metadata at /.well-known/oauth-protected-resource, authorization server metadata, dynamic client registration and client ID metadata documents, PKCE (S256) only, and access tokens that last 30 days with rotating refresh tokens that last 180. Requests are rate limited per token.