Environment Variables

All MCP server configuration is done through environment variables passed in your AI client's MCP server configuration.

Variables

Variable	Required	Description
IONOS_TOKEN	Yes	IONOS CLOUD API token. Authenticates all Compute Engine, Managed Kubernetes, Cloud DNS, Billing, Certificate Manager, , and Activity Log API requests.
IONOS_S3_ACCESS_KEY	No	Object Storage access key. Required for Object Storage data-plane tools (listing objects, reading bucket configuration).
IONOS_S3_SECRET_KEY	No	Object Storage secret key. Required together with IONOS_S3_ACCESS_KEY.
IONOS_MCP_LOAD_MODE	No	Controls how the server registers tools at startup. Accepted values: eager: Registers all tools immediately. This is the default. lazy: Registers only the 45 always-on tools and 2 loader sentinels; Compute and Object Storage register on demand. dynamic (alias search): Registers only the three meta-tools ionos_search_tools, ionos_describe_tools, and ionos_call_tool; the assistant discovers and calls the rest of the catalog through them. Intended for clients with a hard tool cap, such as Cursor. For more information, see Selective Tool Loading.
IONOS_MCP_TOOL_SCOPE	No	Controls whether write tools are registered. The server is read-only unless you set this variable. Accepted values: read: read-only tools only. This is the default, and the fallback for any unrecognised value. write: also registers create_*, update_*, and non-disruptive actions. destructive: also registers delete_* and disruptive actions. Implies write. For more information, see Write Operations.
IONOS_MCP_TRANSPORT	No	Selects the MCP wire transport. Accepted values: stdio: the server runs as a local subprocess and exchanges messages over standard input and output. This is the default, and the fallback for any unrecognised value. http: the server listens on IONOS_MCP_HTTP_ADDR and serves the Streamable HTTP transport. For more information, see Transport.
IONOS_MCP_HTTP_ADDR	No	Listen address for the HTTP transport, for example 127.0.0.1:8080 or :8080. Defaults to 127.0.0.1:8080, which accepts local connections only. Ignored when the transport is stdio.

Command-line flags

The same two settings are also available as flags, which take precedence over the environment variables: --transport <stdio|http> and --http-addr <address>. Use the flags when you start the server yourself rather than letting an AI client start it. For more information, see Transport.

Example

{
  "mcpServers": {
    "ionoscloud": {
      "command": "/path/to/ionoscloud-mcp",
      "env": {
        "IONOS_TOKEN": "your-api-token",
        "IONOS_S3_ACCESS_KEY": "your-access-key",
        "IONOS_S3_SECRET_KEY": "your-secret-key"
      }
    }
  }
}