@spikeonstudio/negative-support-mcp

MCP server for negative.support — generate negative-space print supports (STL/OBJ/STEP) via the official negative-support package. Full API details: negative.support/docs.

Requirements

• Node.js 18+

• A negative.support token (ns_live_…) from negative.support after sign-in

For a local clone, you can put NEGATIVE_SUPPORT_TOKEN=… in a .env file next to package.json (see .env.example). The server loads it via dotenv when the process working directory is that folder. Do not commit .env — it is listed in .gitignore.

Related MCP server: 3D Printer MCP Server

MCP configuration

Use npx — no clone or local npm install required. Set NEGATIVE_SUPPORT_TOKEN, or omit it and call negative_support_activate once per session.

npx normally runs with another cwd, so prefer env in the MCP JSON for Cursor; use .env when you run npm run dev / npm start from this repo.

npm (default)

{
  "mcpServers": {
    "negative-support": {
      "command": "npx",
      "args": ["-y", "@spikeonstudio/negative-support-mcp"],
      "env": {
        "NEGATIVE_SUPPORT_TOKEN": "ns_live_..."
      }
    }
  }
}

From GitHub (same binary name as in package.json bin):

{
  "mcpServers": {
    "negative-support": {
      "command": "npx",
      "args": ["-y", "--package=github:spikeon/negative-support-mcp", "negative-support-mcp"],
      "env": {
        "NEGATIVE_SUPPORT_TOKEN": "ns_live_..."
      }
    }
  }
}

On Windows, if npx is missing, use "command": "npx.cmd" with the same args.

Tools

negative_support_generate: input_path (absolute, on the host running the MCP) is required. Optional: output_stl_path, output_3mf_path, format, margin, angle, min_volume, skip_merge — see negative.support/docs.

Resource: negative-support://docs — short in-server summary.

Timeouts

Generation can take several minutes on large meshes. Many MCP clients use a default tool timeout (often around 60s) unless the call stays “active.” This server emits MCP notifications/progress when the client sends a progressToken with the tool request (about every 15s plus throttled updates from the library), which usually refreshes that timeout.

If a host still cuts you off, use the negative-support CLI for huge models, or raise the tool-timeout in your client if it exposes one.

Development

git clone https://github.com/spikeon/negative-support-mcp.git
cd negative-support-mcp
npm install
npm run build   # or: npm run dev

The server uses stdio; it is started by the MCP host, not run interactively.

Publishing (maintainers)

Pushing to main does not publish. .github/workflows/publish-npm.yml runs npm publish --access public when a v* tag is pushed.

1. Add repository secret NPM_TOKEN (npm access token with publish rights for @spikeonstudio/*).

2. Bump version in package.json (each publish must be a new version).

3. git tag vX.Y.Z && git push origin vX.Y.Z

prepublishOnly runs npm run build. dist/ is committed so GitHub-based npx installs work without a local TypeScript build.

License

MIT. Not affiliated with negative.support; integrates their published npm package and licensing.