npm

@jmrp.io/arcane-mcp is a thin launcher. The server is the release binary, carried by one of six platform packages that npm installs as optional dependencies, only the one whose system and CPU match yours. Nothing runs at install time, nothing is compiled and nothing is downloaded but the packages. Nothing is published until the first release; see Installation.

Requirements

Node.js 18 or later, with npm (for npx). On macOS, macOS 13 or later, which the darwin binaries need.

Platform package	Binary
@jmrp.io/arcane-mcp-linux-x64, -linux-arm64	arcane-mcp-linux-amd64, -arm64
@jmrp.io/arcane-mcp-darwin-x64, -darwin-arm64	arcane-mcp-darwin-amd64, -arm64
@jmrp.io/arcane-mcp-win32-x64, -win32-arm64	arcane-mcp-windows-amd64.exe, -arm64.exe

The Linux binaries are static, so the Linux packages work on musl (Alpine) too. On another system the launcher says which platforms exist.

Run or install

ARCANE_URL=https://arcane.example.com ARCANE_API_KEY=… npx -y @jmrp.io/arcane-mcp

or install it once, which puts an arcane-mcp command on your PATH:

npm install -g @jmrp.io/arcane-mcp
arcane-mcp --version

The launcher runs the binary with standard input and output inherited, on Linux and macOS passes SIGTERM, SIGINT and SIGHUP on to it, and exits with its exit status.

Configure your client

{
  "mcpServers": {
    "arcane": {
      "command": "npx",
      "args": ["-y", "@jmrp.io/arcane-mcp@X.Y.Z"],
      "env": {
        "ARCANE_URL": "https://arcane.example.com",
        "ARCANE_API_KEY": "<your Arcane API key>"
      }
    }
  }
}

-y lets npx install the package without asking, which a client cannot answer. After a global install, the command can be arcane-mcp (its absolute path, $(npm prefix -g)/bin/arcane-mcp, if the client does not see your shell’s PATH). Some clients on Windows cannot start npx directly; there, use "command": "cmd" with "args": ["/c", "npx", "-y", "@jmrp.io/arcane-mcp@X.Y.Z"]. Every client’s entry is on Client setup.

Pin a version

Name the version, @jmrp.io/arcane-mcp@X.Y.Z, as the entry above does; without one, npx may run whatever version it finds. The launcher pins its six platform packages to the same version. The dist-tag latest follows the newest release; a backport is published under release-X.Y and never moves latest.

Verify it

Every version is published from the release workflow through npm trusted publishing, with provenance, and the binaries in the platform packages were checked against the release’s signed checksums.txt before publishing. npm audit signatures in a project that depends on the package checks the registry signatures and the provenance; see Verifying a release.

Update and uninstall

The server never updates itself.

npm update -g @jmrp.io/arcane-mcp     # a global install
npm uninstall -g @jmrp.io/arcane-mcp

With npx, change the version in the client’s entry; npx keeps downloaded versions in npm’s cache (npm cache clean --force empties it).