How to Add Eddyter MCP to Cursor (2-Minute Setup)

Quick answer: To add Eddyter MCP to Cursor, open the Eddyter listing on cursor.directory and click install, or add https://mcp.eddyter.com/mcp to your .cursor/mcp.json. Sign in with your Eddyter account when Cursor asks, pick a license key, then type "Is my Eddyter key valid?" in Agent chat to confirm it works.

That's the whole thing. The rest of this guide walks through each step, shows you what a working connection looks like, and covers the five errors people actually hit.

What you need before you start

Two things. That's it.

1. Cursor, any recent version with MCP support.
2. An Eddyter account with an active license key. Grab one from your license key dashboard. The free plan works. The MCP server reads and manages keys but can't create them, so do this first.

You don't need Node, npm or an API key in your config. The hosted Eddyter MCP server signs you in with OAuth.

Method 1: One-click install (fastest)

Step 1. Open the Eddyter listing

Go to cursor.directory/plugins/eddyter and click Add to Cursor. Your browser will ask to open Cursor. Allow it.

What goes wrong: nothing opens. Usually the browser blocked the cursor:// handoff. Check for a small popup-blocked icon in the address bar, or skip to Method 2.

Step 2. Confirm the install in Cursor

Cursor shows an install prompt for the Eddyter server. Confirm it, and Eddyter appears in your MCP server list.

Step 3. Sign in

The first time the agent calls an Eddyter tool, Cursor opens a browser tab for sign-in. Log in with your Eddyter account, choose which license key Cursor should act on, and approve.

What goes wrong: you have several keys (staging, production, a client project) and pick the wrong one. Every answer the agent gives will then be about that key. If numbers look off later, this is the first thing to check.

Step 4. Test it

Open the chat panel in Agent mode and type:

Is my Eddyter key valid?

Cursor will ask permission to run verify_status. Approve it. Here's what came back when we ran it on our own key:

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Status: ✅ valid (active)
Plan: AI Pro (Managed) — paid
Subscription: trialing
Expires: 2027-10-27 (363 day(s) left)
BYOK mode: off (managed credits)
Live API: no • domain: localhost

If you see something like this, you're done. Total time: about two minutes, most of it spent on the sign-in screen.

Method 2: Add it manually with mcp.json

Some teams prefer config in the repo so every developer gets the same tools. Here's how.

Step 1. Pick the scope

Cursor reads MCP config from two places:

Our take: put it in the project file. The editor belongs to one app, and committing the config means a new teammate gets Eddyter tools the moment they open the repo. There's no secret in it, so it's safe to commit.

Step 2. Paste the config

Create the file if it doesn't exist and add:

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{
  "mcpServers": {
    "eddyter": {
      "type": "http",
      "url": "https://mcp.eddyter.com/mcp"
    }
  }
}

Already have other servers? Add the "eddyter" block inside your existing mcpServers object. Don't create a second mcpServers key.

What goes wrong: a trailing comma after the last server. Cursor's JSON parser rejects the whole file, and all your MCP servers disappear, not only Eddyter. Run it through a JSON validator if the list comes up empty.

Step 3. Reload and sign in

Open Cursor's MCP settings (the location has moved between releases; recent builds keep it under the Customize page, older ones under Settings → Tools & Integrations → MCP). Toggle Eddyter on or hit refresh. Then follow Steps 3 and 4 from Method 1.

Prefer a local server? (npx option)

If your company blocks OAuth to third-party services, run the server locally with your key instead:

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{
  "mcpServers": {
    "eddyter": {
      "command": "npx",
      "args": ["-y", "eddyter-mcp"],
      "env": { "EDDYTER_LICENSE_KEY": "${env:EDDYTER_LICENSE_KEY}" }
    }
  }
}

Two notes. First, the ${env:...} syntax pulls the key from your shell, so it never lands in Git. Second, local installs are read-only by default. If you want the agent to toggle editor features, add "EDDYTER_ALLOW_WRITES": "true" to env. We'd leave it off for most of the team.

What you can do once it's connected

Once connected, Cursor gets five Eddyter tools:

The first prompt is the one worth trying today. In a Next.js App Router project, the agent writes two files: an Editor.tsx marked 'use client', and an EditorClient.tsx that loads it with next/dynamic and ssr: false. That second file is the bit everyone forgets, and it's why you'd otherwise see window is not defined on your first npm run dev.

On a Vite project the same prompt is shorter. No SSR boundary, one component, and the key goes in VITE_EDDYTER_API_KEY. The tool knows the difference, so you don't have to.

Snippets currently cover React, Next.js (App Router and Pages Router), Vite and Remix. For Vue, Angular, Svelte or Laravel, use the quick install guide.

Troubleshooting: Eddyter MCP not working in Cursor

1. Tools don't show up at all. Check that the server is toggled on in MCP settings and shows a green status. If it's red, open the Output panel, pick MCP Logs from the dropdown, and read the error. Usually it's a JSON typo or a mistyped URL (it's /mcp at the end, not /sse).

2. The agent answers without calling Eddyter. You're probably in Ask mode. MCP tools run from Agent chat. You can also be explicit: "Use the Eddyter MCP to check my license."

3. "Unauthorized" or the sign-in loop. Your OAuth session expired or you revoked access. Toggle the server off and on, and sign in again when prompted.

4. Wrong plan or wrong usage numbers. You connected a different license key than you think. Ask "Which Eddyter key am I connected to?" and reconnect with the right one if needed.

5. update_config is missing. On a local npx install, writes are off until you set EDDYTER_ALLOW_WRITES=true. On the hosted server, it's available but limited to features your plan allows.

One more Cursor-specific gotcha: if you run lots of MCP servers, Cursor may not pass every tool to the agent. Disable servers you aren't using in this project.

FAQ

Is the Eddyter MCP server free?

Yes. The server is MIT licensed and free to use. You need an Eddyter account with an active license key, and the free plan works. See pricing for what each plan includes.

Do I need to put my API key in mcp.json?

No. The hosted server at https://mcp.eddyter.com/mcp uses OAuth, so Cursor signs you in through the browser. Only the local npx option needs a key, and you can load it from an environment variable.

Should I use project or global mcp.json?

Use the project file (.cursor/mcp.json) if one app uses Eddyter and your team shares the repo. Use the global file (~/.cursor/mcp.json) if you work with Eddyter across several projects.

Can Cursor change my live editor settings?

Only through update_config, and only for features your plan allows. Changes apply to the editor's feature toggles, not your code. Local installs keep writes off unless you enable them.

Does this work in Claude or ChatGPT too?

Yes. The same server URL works in Claude.ai, Claude Desktop, Claude Code, Codex and ChatGPT Developer Mode. Setup steps for each are on the Eddyter MCP page.

Which frameworks get auto-generated setup code?

React, Next.js (App Router and Pages Router), Vite and Remix. Eddyter itself also supports Vue, Angular, Svelte, Laravel, Vanilla JS and React Native.

Next step

Open Cursor, install from cursor.directory/plugins/eddyter, and ask: "Add Eddyter to my app." If you'd rather watch first, the Eddyter MCP page has a short video of the full install. Want to know why we built an MCP server into a rich text editor in the first place? Read The First Rich Text Editor With Native MCP Support.