caffeine

Caffeine for Cursor

Build and ship Caffeine apps without leaving Cursor. The plugin wires Cursor to the Caffeine MCP server, then adds rules, skills, and commands so the agent knows how to use it.

Caffeine builds full-stack apps on the Internet Computer — a Motoko backend with a web frontend. You describe what you want; Caffeine's own agent writes the code, builds it, and deploys it to a draft URL. This plugin lets Cursor do that driving, and gets out of the way when you'd rather edit the Motoko yourself.

What you get

• MCP connection to https://mcp.caffeine.ai/mcp. On first use it opens a browser to sign in to your Caffeine account (OAuth, with dynamic client registration and PKCE). No keys to paste, no token to configure.
• Skills the agent reaches for on its own:
  • scaffold-caffeine-project — start a project from a brief
  • iterate-with-caffeine-agent — make and verify changes on an existing project
  • manage-caffeine-projects — list, inspect, and clean up projects
  • caffeine-local-development — pull the source down and edit it here instead
• Commands you can run directly: /caffeine-new, /caffeine-iterate, /caffeine-projects, /caffeine-local, /caffeine-help.
• Rules that keep the agent honest: follow a chat session to a stable state, answer its clarifications, and check draftState before claiming a change shipped.

Install

Add this marketplace in Cursor, then enable the Caffeine plugin. The first call to a Caffeine tool triggers the sign-in.

If you only want the raw connection without the skills and commands, add the server to your Cursor MCP config:

{
  "mcpServers": {
    "caffeine": {
      "type": "http",
      "url": "https://mcp.caffeine.ai/mcp"
    }
  }
}

Using it

Start something new:

/caffeine-new a client portal where customers log in, see their invoices, and mark one as paid

Change something that exists:

/caffeine-iterate on the invoices page, move the "Mark paid" button into the row and disable it once an invoice is paid

Check what you have:

/caffeine-projects

How the workflow actually goes

Creating a project is two steps. caffeine_create_project takes no arguments and returns an empty project with an auto-derived name — your brief reaches the agent as the first message of a chat session. The skills handle this; it is worth knowing if you call the tools directly.

Work then happens in chat sessions. caffeine_chat_start_session waits a bounded time and hands back a continuation hint if the agent is still going. A session can also block on a question — a plain clarification answered with caffeine_chat_reply, or a structured form answered with caffeine_chat_submit_form. A blocked session sits there until someone answers it.

Every project carries a draftState (no_draft, deploying, deployed, expired) alongside a draftUrl and a liveUrl. The draft is the work in progress; the live URL is what the public sees and only changes when you publish. The agent saying it made a change is not the same as a draft that reached deployed.

Editing the code yourself

/caffeine-local switches to the other path: install the Caffeine CLI, download the project's source into your workspace, edit the Motoko directly, validate, and upload it back. caffeine_local_setup returns the authoritative steps, including a device-login flow that completes without a browser round trip.

Two upstream skills carry the real detail, and the plugin's rules tell the agent to fetch them before writing any Motoko:

• Project structure and the build/check/preview loop — https://skills.internetcomputer.org/skills/caffeine-app/SKILL.md
• The Motoko language — https://skills.internetcomputer.org/skills/motoko/SKILL.md

Don't run an agent chat session that edits code while you have local changes pending. Both write to the same project and the last one to finish wins.

Hosted versus local MCP server

This plugin connects to the hosted server, which is why sign-in is a browser flow and there is nothing to install. The hosted server deliberately leaves out the tools that touch a filesystem or run builds: caffeine_build, caffeine_check, caffeine_preview, caffeine_clone_project, caffeine_doctor, caffeine_export_project, caffeine_import_project, and the caffeine_config_* family. Run the equivalent CLI commands in the terminal instead.

If you want those as MCP tools, run the Caffeine MCP server locally over stdio and point Cursor at it instead. That build ships through GitHub Packages and needs an .npmrc with a read:packages token, so it is currently an internal path — Caffeine staff should follow the MCP installation guide in the CLI repo.

A few things worth knowing

• The code lives in Caffeine's build environment, not your local repo, unless you deliberately pull it down.
• caffeine_delete_project is permanent. The rules tell the agent to confirm the exact project first — keep that.
• Accounts have a per-plan project limit, and creation fails once you hit it. An abandoned empty project still counts.
• clarificationLevel: "guided" is worth setting when a change is open-ended or touches the data model; it makes the agent ask before it commits to an approach.

Links

• Caffeine: https://caffeine.ai
• Plugin source and issues: https://github.com/caffeinelabs/caffeine-cursor-plugin