Floor Plan MCP: Connect Claude, ChatGPT and Cursor

A floor plan MCP server lets an AI app read and edit a real plan instead of describing one. FloorGen runs a Model Context Protocol server at https://floorgen.app/mcp, over Streamable HTTP. Any client that speaks MCP can read your projects, draw walls, place doors, run the code checks and pull the area schedule through it. This post covers the setup for the five clients we get asked about most, and the one choice you make before any of them: an API key or a sign-in. For how this differs from a standalone tool, see AI floor plan generators.

Keys or sign-in

The rule is simple. If the client lets you set an Authorization header, use a key. If it only takes a URL (claude.ai, ChatGPT, the connector screen in Claude Desktop), it will sign you in with OAuth and you never handle a key.

• API keys are made in FloorGen under your account, in Agents & MCP. Each key has an access level (Read only, Read & edit, or Full, which can delete), a project scope (all projects, or up to 100 chosen ones) and an expiry (30, 90 or 365 days, or never). Keys start with fg_live_. The full key is shown once when you create it; the server stores only a hash of it, so copy it then.
• OAuth follows the 2.1 flow with PKCE (S256 only). When the client opens the FloorGen consent page you pick the access level for that app: Read only, Read & edit, or Full. Access tokens last an hour and refresh tokens 30 days. A refresh token works once; if a used one is presented again, the whole grant is revoked. Apps connected this way are listed in Agents & MCP, where you can disconnect them.
• A sign-in covers all your projects. If you want an agent limited to one job's drawings, use a key with chosen projects.

Whichever you use, the server only lists tools the credential is allowed to call. A read-only key never sees the write tools at all.

Claude Code

Put the key in your environment, then add the server. --scope user makes it available in every project; leave it out to add it for the current folder only.

export FLOORGEN_API_KEY="fg_live_PASTE_YOUR_KEY"

claude mcp add --transport http --scope user floorgen https://floorgen.app/mcp \
  --header "Authorization: Bearer $FLOORGEN_API_KEY"

The shell expands the variable when you run the command, and Claude Code stores the resulting header in ~/.claude.json. To share the setup with a team without sharing a key, commit an .mcp.json that reads the variable at runtime instead:

{
  "mcpServers": {
    "floorgen": {
      "type": "http",
      "url": "https://floorgen.app/mcp",
      "headers": { "Authorization": "Bearer ${FLOORGEN_API_KEY}" }
    }
  }
}

Check it with claude mcp list, or /mcp inside a session.

Claude Desktop

The quickest route is the same as claude.ai: Settings → Connectors → Add custom connector, paste the URL and sign in. If you would rather use a key, edit the config file (Settings → Developer → Edit Config). That file only starts local commands, so mcp-remote (Node 18 or later) bridges to the hosted server:

{
  "mcpServers": {
    "floorgen": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://floorgen.app/mcp",
               "--header", "Authorization:${FLOORGEN_AUTH}"],
      "env": { "FLOORGEN_AUTH": "Bearer fg_live_PASTE_YOUR_KEY" }
    }
  }
}

Note there is no space after Authorization:. Windows splits arguments on spaces, and the header would arrive broken. The file lives at ~/Library/Application Support/Claude/claude_desktop_config.json on macOS and %APPDATA%\Claude\claude_desktop_config.json on Windows. Quit and reopen the app; FloorGen appears in the tools menu.

claude.ai

Custom connectors on claude.ai take a URL and nothing else; there is no header field. Go to Settings → Connectors → Add custom connector:

Name: FloorGen
Remote MCP server URL: https://floorgen.app/mcp

Click Connect, sign in to FloorGen and choose the access level. A connector added on claude.ai also shows up in Claude Desktop and the mobile apps. Enable it in a chat from the tools menu.

ChatGPT

ChatGPT works the same way as claude.ai: a URL and a sign-in. Turn on developer mode first (Settings → Apps & Connectors → Advanced settings → Developer mode), then create a connector:

Name: FloorGen
MCP server URL: https://floorgen.app/mcp
Authentication: OAuth

Write tools need developer mode. To check the connection, pick the connector in a chat and ask it to list your FloorGen projects.

Cursor

Cursor reads ~/.cursor/mcp.json for all projects, or .cursor/mcp.json inside one. It expands ${env:NAME} from your environment, so the file itself holds no key and is safe to commit:

{
  "mcpServers": {
    "floorgen": {
      "url": "https://floorgen.app/mcp",
      "headers": { "Authorization": "Bearer ${env:FLOORGEN_API_KEY}" }
    }
  }
}

In Cursor Settings → MCP, floorgen should show a green dot and its tool count.

Seeing more than the core tools

The server has 151 tools, grouped into seven toolsets: core, more, stairs, trace, live, macros and history. By default it lists only core (44 tools covering projects, floors, walls, rooms, doors and windows, furniture, apply_ops for batches, validate_plan and undo), which keeps the tool list short enough for a model to choose well. To list more, add them to the URL as a comma-separated query, or ask for everything:

https://floorgen.app/mcp?toolsets=core,stairs,history
https://floorgen.app/mcp?toolsets=all

Clients that let you set headers can send X-FloorGen-Toolsets with the same value instead. The trace toolset is what lets an agent place and scale a floor plan image for you.

A first session

Start with reads. Ask the agent to list your projects (list_projects) and describe one (describe_project): floors, rooms with their areas, doors and windows. Then try one small edit on a copy, and open the same project in the browser. Edits show up in the open editor as they are made, and each one is a single step you can undo. For prompts that work well, see can ChatGPT or Claude draw a floor plan.

Agents & MCP in the app also has tested setup for VS Code with Copilot, Windsurf, Codex CLI, Gemini CLI and Cline, with your key filled in when you have just created one. Before you give an agent edit or delete access, read how FloorGen keeps agent edits reversible. To try it, create an account or see the agents overview.

Every tool the server offers is listed, by area, in the MCP server reference.