name	create-pi-host
description	Create a new Raspberry Pi cluster host configuration
compatibility	Requires nix, git
metadata	{"author":"ruinous.ai","version":"1.1"}
parameters	{"pi_model":{"type":"select","description":"Raspberry Pi model","required":true,"options":[{"label":"Pi 5 (Recommended)","description":"Raspberry Pi 5 - newer, faster"},{"label":"Pi 4","description":"Raspberry Pi 4 - older model"}]},"member_name":{"type":"select","description":"NATO phonetic alphabet name for the cluster member","required":true,"options":[{"label":"alpha","description":"First letter"},{"label":"bravo","description":"Second letter"},{"label":"charlie","description":"Third letter"},{"label":"delta","description":"Fourth letter"},{"label":"echo","description":"Fifth letter"},{"label":"foxtrot","description":"Sixth letter"},{"label":"golf","description":"Seventh letter"},{"label":"hotel","description":"Eighth letter"},{"label":"india","description":"Ninth letter"},{"label":"juliet","description":"Tenth letter"},{"label":"Enter other...","description":"kilo, lima, mike, november, oscar, papa, quebec, romeo, sierra, tango, uniform, victor, whiskey, xray, yankee, zulu"}]}}

Create Raspberry Pi Host

Create a new Raspberry Pi host for the RPC (Raspberry Pi Cluster).

Parameter Handling

If parameters are missing from $ARGUMENTS, use mcp_question to gather them:

mcp_question({
  questions: [
    {
      question: "Which Raspberry Pi model is this?",
      header: "Model",
      options: [
        { label: "Pi 5 (Recommended)", description: "Raspberry Pi 5" },
        { label: "Pi 4", description: "Raspberry Pi 4" }
      ]
    },
    {
      question: "What NATO phonetic name for this cluster member?",
      header: "Name",
      options: [
        { label: "alpha", description: "First letter" },
        { label: "bravo", description: "Second letter" },
        { label: "charlie", description: "Third letter" },
        { label: "delta", description: "Fourth letter" },
        { label: "echo", description: "Fifth letter" },
        { label: "foxtrot", description: "Sixth letter" },
        { label: "golf", description: "Seventh letter" },
        { label: "hotel", description: "Eighth letter" },
        { label: "Enter other...", description: "india, juliet, kilo, lima, etc." }
      ]
    }
  ]
})

Expected $ARGUMENTS format: rpc-<model>-<name>

Example: rpc-5-alpha (Pi 5, first member)
Example: rpc-4-echo (Pi 4, fifth member)

Alternative format: <model> <name> which will be combined to rpc-<model>-<name>

Example: 5 india → rpc-5-india

Naming Convention

rpc = Raspberry Pi Cluster prefix
<model> = Pi model: 4 for Pi 4, 5 for Pi 5
<name> = NATO phonetic alphabet (alpha, bravo, charlie, delta, echo, foxtrot, golf, hotel, india, juliet, kilo, lima, mike, november, oscar, papa, quebec, romeo, sierra, tango, uniform, victor, whiskey, xray, yankee, zulu)

Steps

Parse and validate the hostname from $ARGUMENTS
- Must match pattern rpc-[45]-(alpha|bravo|charlie|delta|echo|foxtrot|golf|hotel|india|juliet|kilo|lima|mike|november|oscar|papa|quebec|romeo|sierra|tango|uniform|victor|whiskey|xray|yankee|zulu)
- Extract the model number (4 or 5)
- Extract the member name (NATO phonetic alphabet)
- If invalid, ask the user to provide a valid hostname
Check if host already exists:
```
ls hosts/$HOSTNAME 2>/dev/null
```
If exists, warn user and ask to confirm overwrite

Create directory structure:

mkdir -p hosts/$HOSTNAME/users/jmeskill

Create configuration.nix at hosts/$HOSTNAME/configuration.nix:

{
  flake,
  inputs,
  lib,
  pkgs,
  ...
}: {
  imports = [
    flake.nixosModules.default
    flake.nixosModules.server

    ./hardware-configuration.nix
  ];

  networking.hostName = "$HOSTNAME";

  # Use the recommended "kernel" bootloader for Raspberry Pi
  boot.loader.raspberryPi.bootloader = "kernel";

  # Resolve nixpkgs registry conflict between main nixpkgs and nixos-raspberrypi's nixpkgs
  nix.registry.nixpkgs.to = lib.mkForce {
    type = "path";
    path = inputs.nixpkgs.outPath;
  };

  # Disable UPS monitoring (no UPS connected to this Pi)
  power.ups.enable = lib.mkForce false;

  # Enable SSH for remote access
  services.openssh = {
    enable = true;
    settings = {
      PasswordAuthentication = false;
      PermitRootLogin = "prohibit-password";
    };
  };

  # User configuration
  users.users.jmeskill = {
    uid = 1000;
    isNormalUser = true;
    description = "Jade Meskill";
    extraGroups = ["wheel"];
    openssh.authorizedKeys.keys = [
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIL8rjXP/sjewv6kM1aTtNWkVZKJpZvIAXIRqL81IyEsm iamruinous@ruinous.social"
    ];
    shell = pkgs.fish;
  };

  security.sudo.wheelNeedsPassword = false;
  users.mutableUsers = lib.mkForce true;
  users.defaultUserShell = lib.mkForce pkgs.fish;

  system.stateVersion = "25.11";
}

Create hardware-configuration.nix at hosts/$HOSTNAME/hardware-configuration.nix:

{lib, ...}: {
  # Hardware configuration for Raspberry Pi $MODEL
  # Most hardware config is handled by nixos-raspberrypi modules

  hardware.enableRedistributableFirmware = true;

  # File system configuration for SD card boot
  # NOTE: Update these labels after imaging if needed
  fileSystems."/" = {
    device = "/dev/disk/by-label/NIXOS_SD";
    fsType = "ext4";
  };

  fileSystems."/boot/firmware" = {
    device = "/dev/disk/by-label/FIRMWARE";
    fsType = "vfat";
    options = ["noatime"];
  };

  swapDevices = [];

  networking.useDHCP = lib.mkDefault true;

  nixpkgs.hostPlatform = "aarch64-linux";
}

Create user home-configuration.nix at hosts/$HOSTNAME/users/jmeskill/home-configuration.nix:
```
{flake, ...}: {
  imports = [
    flake.homeModules.default
  ];
}
```

Add to piHosts in flake.nix:

Find the piHosts = { section and add the new host entry. Use the correct modules based on model:

For Pi 5:

$HOSTNAME = inputs.nixos-raspberrypi.lib.nixosSystem {
  specialArgs = {
    inherit inputs;
    flake = inputs.self;
    nixos-raspberrypi = inputs.nixos-raspberrypi;
    perSystem = {
      self = blueprintOutputs.packages.aarch64-linux;
    };
  };
  modules = [
    inputs.nixos-raspberrypi.nixosModules.raspberry-pi-5.base
    inputs.nixos-raspberrypi.nixosModules.raspberry-pi-5.display-vc4
    inputs.nixos-raspberrypi.nixosModules.sd-image
    ./hosts/$HOSTNAME/configuration.nix
  ];
};

For Pi 4:

$HOSTNAME = inputs.nixos-raspberrypi.lib.nixosSystem {
  specialArgs = {
    inherit inputs;
    flake = inputs.self;
    nixos-raspberrypi = inputs.nixos-raspberrypi;
    perSystem = {
      self = blueprintOutputs.packages.aarch64-linux;
    };
  };
  modules = [
    inputs.nixos-raspberrypi.nixosModules.raspberry-pi-4.base
    inputs.nixos-raspberrypi.nixosModules.raspberry-pi-4.display-vc4
    inputs.nixos-raspberrypi.nixosModules.sd-image
    ./hosts/$HOSTNAME/configuration.nix
  ];
};

Update hosts/raspberry-pi/README.md - Add the new host to the "Cluster Members" table

Verify the configuration builds:

nix eval .#nixosConfigurations.$HOSTNAME.config.system.build.toplevel.outPath

Output summary:

Created new Raspberry Pi host: $HOSTNAME

Files created:
- hosts/$HOSTNAME/configuration.nix
- hosts/$HOSTNAME/hardware-configuration.nix
- hosts/$HOSTNAME/users/jmeskill/home-configuration.nix

Build SD image:
  nix build .#nixosConfigurations.$HOSTNAME.config.system.build.sdImage \
    --builders "ssh://armistice.meskill.farm aarch64-linux" --max-jobs 0

Flash to SD card:
  zstd -d result/sd-image/*.img.zst -o nixos-$HOSTNAME.img
  sudo dd if=nixos-$HOSTNAME.img of=/dev/sdX bs=4M status=progress

Example Usage

/create-pi-host rpc-5-alpha
/create-pi-host rpc-4-bravo
/create-pi-host rpc-5-charlie