--- a/README.adoc
+++ b/README.adoc
@@ -63,18 +63,14 @@
       # nixosModules section of fleet config declares modules, which are used for all configured nixos hosts.
       nixosModules = [
         lanzaboote.nixosModules.lanzaboote
-        ({
-          config,
-          lib,
-          ...
-        }: {
+        {
           # Make `nix shell nixpkgs#thing` use the same nixpkgs, as used to build the system.
           nix.registry.nixpkgs = {
             from = { id = "nixpkgs"; type = "indirect"; };
             flake = nixpkgs;
             exact = false;
           };
-        })
+        }
       ];
 
       # Those modules are used to configure all the machines in cluster at the same time, good example of global modules
@@ -97,12 +93,12 @@
           ./controlplane-1/hardware-configuration.nix
           ./controlplane-1/configuration.nix
           # Configuration may also be specified inline, as in any nixos config.
-          ({...}: {
+          {
             services.ray = {
               gpus = 4;
               cpus = 128;
             };
-          })
+          }
         ];
       };
     };
--- a/flake.nix
+++ b/flake.nix
@@ -16,19 +16,18 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
   };
-  outputs = {
+  outputs = inputs @ {
     self,
-    rust-overlay,
     flake-parts,
-    nixpkgs,
-    nixpkgs-stable-for-tests,
     crane,
+    ...
   }:
     flake-parts.lib.mkFlake {
-      # Not passing inputs through inputs for better visibility.
-      inputs = {};
+      inherit inputs;
     } {
-      flake = {
+      flake = let
+        inherit (inputs.nixpkgs.lib) mapAttrs;
+      in {
         lib = import ./lib {
           fleetPkgsForPkgs = pkgs:
             import ./pkgs {
@@ -45,11 +44,11 @@
             '';
             inventory = output: {
               children =
-                builtins.mapAttrs (configName: cluster: {
+                mapAttrs (configName: cluster: {
                   what = "fleet cluster configuration";
 
                   children =
-                    builtins.mapAttrs (hostName: host: {
+                    mapAttrs (hostName: host: {
                       what = "host [${host.system}]";
                     })
                     cluster.config.hosts;
@@ -70,19 +69,20 @@
         pkgs,
         ...
       }: let
+        inherit (lib) mapAttrs' elem;
         # Can also be built for darwin, through it is not usual to deploy nixos systems from macos machines.
         # I have no hardware for such testing, thus only adding machines I actually have and use.
         #
         # It is not possible to deploy any host from armv6/armv7 hardware, and I don't think it even makes sense.
         deployerSystems = ["aarch64-linux" "x86_64-linux"];
-        deployerSystem = builtins.elem system deployerSystems;
+        deployerSystem = elem system deployerSystems;
         lib = pkgs.lib;
         rust = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
         craneLib = (crane.mkLib pkgs).overrideToolchain rust;
       in {
-        _module.args.pkgs = import nixpkgs {
+        _module.args.pkgs = import inputs.nixpkgs {
           inherit system;
-          overlays = [(rust-overlay.overlays.default)];
+          overlays = [(inputs.rust-overlay.overlays.default)];
         };
         # Reference fleet package should be built with nightly rust, specified in rust-toolchain.toml.
         packages = lib.mkIf deployerSystem (let
@@ -116,14 +116,14 @@
         checks = let
           packages = import ./pkgs {
             inherit (pkgs) callPackage;
-            craneLib = crane.mkLib (import nixpkgs {inherit system;});
+            craneLib = crane.mkLib pkgs;
           };
           packages-with-nixpkgs-stable = import ./pkgs {
             inherit (pkgs) callPackage;
-            craneLib = crane.mkLib (import nixpkgs-stable-for-tests {inherit system;});
+            craneLib = crane.mkLib (import inputs.nixpkgs-stable-for-tests {inherit system;});
           };
           prefixAttrs = prefix: attrs:
-            nixpkgs.lib.attrsets.mapAttrs' (name: value: {
+            mapAttrs' (name: value: {
               name = "${prefix}${name}";
               value = value.overrideAttrs (prev: {
                 pname = "${prefix}${prev.pname}";
--- a/lib/fleetLib.nix
+++ b/lib/fleetLib.nix
@@ -2,8 +2,11 @@
 {
   nixpkgs,
   hostNames,
-}:
-with nixpkgs.lib; rec {
+}: let
+  inherit (nixpkgs) lib;
+  inherit (lib) listToAttrs remove unique crossLists sort elemAt mkOptionType mkOverride optionalString;
+  inherit (lib.types) listOf coercedTo oneOf submodule;
+in rec {
   hostsToAttrs = f:
     listToAttrs (
       map (name: {
@@ -34,6 +37,27 @@
     then "${this}-${other}"
     else "${other}-${this}";
 
+  types = rec {
+    anyModule = mkOptionType {
+      name = "submodule";
+      inherit (submodule {}) check;
+      merge = lib.options.mergeOneOption;
+      description = "Nixos module";
+    };
+    listOfAnyModuleStrict =
+      listOf anyModule;
+    listOfAnyModule =
+      coercedTo (oneOf [listOfAnyModuleStrict anyModule]) (
+        v:
+          if builtins.isAttrs v
+          then [v]
+          else if builtins.isFunction v
+          then [v]
+          else v
+      )
+      listOfAnyModuleStrict;
+  };
+
   # mkDefault = mkOverride 1000
   # For places, where fleet knows better than nixpkgs defaults.
   mkFleetDefault = mkOverride 999;
--- a/modules/fleet/assertions.nix
+++ b/modules/fleet/assertions.nix
@@ -1,8 +1,10 @@
-{lib, ...}:
-with lib; {
+{lib, ...}: let
+  inherit (lib) mkOption;
+  inherit (lib.types) listOf unspecified str;
+in {
   options = {
     assertions = mkOption {
-      type = types.listOf types.unspecified;
+      type = listOf unspecified;
       internal = true;
       default = [];
       example = [
@@ -21,7 +23,7 @@
     warnings = mkOption {
       internal = true;
       default = [];
-      type = types.listOf types.str;
+      type = listOf str;
       example = ["The `foo' service is deprecated and will go away soon!"];
       description = ''
         This option allows modules to show warnings to users during
--- a/modules/fleet/meta.nix
+++ b/modules/fleet/meta.nix
@@ -4,58 +4,53 @@
   config,
   nixpkgs,
   ...
-}:
-with lib;
-with fleetLib; let
-  hostModule = with types;
-    {...} @ hostConfig: let
-      hostName = hostConfig.config._module.args.name;
-    in {
-      options = {
-        nixosModules = mkOption {
-          type = listOf (mkOptionType {
-            name = "submodule";
-            inherit (submodule {}) check;
-            merge = lib.options.mergeOneOption;
-            description = "Nixos module";
-          });
-          description = "List of nixos modules";
-          default = [];
-        };
-        system = mkOption {
-          type = str;
-          description = "Type of system";
-        };
-        encryptionKey = mkOption {
-          type = str;
-          description = "Encryption key";
-        };
-        nixosSystem = mkOption {
-          type = unspecified;
-          description = "Nixos configuration";
-        };
-        nixpkgs = mkOption {
-          type = unspecified;
-          description = "Nixpkgs override";
-          default = nixpkgs;
-        };
+}: let
+  inherit (fleetLib) hostsToAttrs mkFleetGeneratorDefault;
+  inherit (fleetLib.types) listOfAnyModule;
+  inherit (lib) mkOption mkOptionType;
+  inherit (lib.types) str unspecified attrsOf listOf submodule;
+  hostModule = {...} @ hostConfig: let
+    hostName = hostConfig.config._module.args.name;
+  in {
+    options = {
+      nixosModules = mkOption {
+        # Not too strict, but nixos module system will fix everything.
+        type =
+          listOfAnyModule;
+
+        description = "List of nixos modules";
+        default = [];
+      };
+      system = mkOption {
+        type = str;
+        description = "Type of system";
+      };
+      encryptionKey = mkOption {
+        type = str;
+        description = "Encryption key";
+      };
+      nixosSystem = mkOption {
+        type = unspecified;
+        description = "Nixos configuration";
+      };
+      nixpkgs = mkOption {
+        type = unspecified;
+        description = "Nixpkgs override";
+        default = nixpkgs;
       };
-      config = {
-        nixosSystem = hostConfig.config.nixpkgs.lib.nixosSystem {
-          inherit (hostConfig.config) system;
-          modules = hostConfig.config.nixosModules;
-          specialArgs = {
-            inherit fleetLib;
-            fleet = hostsToAttrs (host: config.hosts.${host}.nixosSystem.config);
-          };
+    };
+    config = {
+      nixosSystem = hostConfig.config.nixpkgs.lib.nixosSystem {
+        inherit (hostConfig.config) system;
+        modules = hostConfig.config.nixosModules;
+        specialArgs = {
+          inherit fleetLib;
+          fleet = hostsToAttrs (host: config.hosts.${host}.nixosSystem.config);
         };
-        nixosModules = [
-          ({...}: {
-            networking.hostName = mkFleetGeneratorDefault hostName;
-          })
-        ];
       };
+      nixosModules.networking.hostName = mkFleetGeneratorDefault hostName;
     };
+  };
   overlayType = mkOptionType {
     name = "nixpkgs-overlay";
     description = "nixpkgs overlay";
@@ -63,19 +58,14 @@
     merge = lib.mergeOneOption;
   };
 in {
-  options = with types; {
+  options = {
     hosts = mkOption {
       type = attrsOf (submodule hostModule);
       default = {};
       description = "Configurations of individual hosts";
     };
     nixosModules = mkOption {
-      type = listOf (mkOptionType {
-        name = "submodule";
-        inherit (submodule {}) check;
-        merge = lib.options.mergeOneOption;
-        description = "Nixos modules";
-      });
+      type = listOfAnyModule;
       description = "Modules, which should be added to every system";
       default = [];
     };
@@ -89,9 +79,9 @@
       nixosModules =
         config.nixosModules
         ++ [
-          ({...}: {
+          {
             nixpkgs.overlays = config.overlays;
-          })
+          }
         ];
     });
     nixosModules = import ../../nixos/modules/module-list.nix;
--- a/modules/fleet/secrets.nix
+++ b/modules/fleet/secrets.nix
@@ -3,11 +3,13 @@
   fleetLib,
   config,
   ...
-}:
-with lib;
-with fleetLib; let
-  sharedSecret = with types; ({config, ...}: {
-    freeformType = types.lazyAttrsOf unspecified;
+}: let
+  inherit (fleetLib) hostsToAttrs;
+  inherit (lib) mkOption mapAttrsToList mapAttrs filterAttrs concatStringsSep;
+  inherit (lib.types) lazyAttrsOf unspecified nullOr listOf str bool attrsOf submodule;
+
+  sharedSecret = {config, ...}: {
+    freeformType = lazyAttrsOf unspecified;
     options = {
       expectedOwners = mkOption {
         type = nullOr (listOf str);
@@ -66,9 +68,9 @@
         default = [];
       };
     };
-  });
-  hostSecret = with types; {
-    freeformType = types.lazyAttrsOf unspecified;
+  };
+  hostSecret = {
+    freeformType = lazyAttrsOf unspecified;
     options = {
       createdAt = mkOption {
         type = nullOr str;
@@ -81,7 +83,7 @@
     };
   };
 in {
-  options = with types; {
+  options = {
     version = mkOption {
       type = str;
       default = "";
@@ -128,11 +130,7 @@
     });
     # TODO: Should this attribute be moved to `nixpkgs.overlays`?
     overlays = [
-      (final: prev: let
-        lib = final.lib;
-        inherit (lib) strings;
-        inherit (strings) concatStringsSep;
-      in {
+      (final: prev: {
         mkSecretGenerators = {recipients}: rec {
           # TODO: Merge both generators to one with consistent options syntax?
           # Impure generator is built on local machine, then built closure is copied to remote machine,
--- a/nixos/meta.nix
+++ b/nixos/meta.nix
@@ -2,11 +2,13 @@
   lib,
   pkgs,
   ...
-}:
-with lib; {
-  options = with types; {
+}: let
+  inherit (lib) mkOption;
+  inherit (lib.types) listOf str submodule;
+in {
+  options = {
     nixpkgs.resolvedPkgs = mkOption {
-      type = types.pkgs // {description = "nixpkgs.pkgs";};
+      type = lib.types.pkgs // {description = "nixpkgs.pkgs";};
       description = "Value of pkgs";
     };
     tags = mkOption {
@@ -30,9 +32,6 @@
         };
       };
       description = "Network definition of host";
-    };
-    buildTarget = mkOption {
-      type = enum ["toplevel" "sd-image" "installation-cd"];
     };
   };
   config = {
--- a/nixos/secrets.nix
+++ b/nixos/secrets.nix
@@ -3,16 +3,17 @@
   config,
   pkgs,
   ...
-}:
-with lib; let
+}: let
   inherit (lib.strings) hasPrefix removePrefix;
+  inherit (lib) mkOption mkOptionDefault mapAttrs stringAfter;
+  inherit (lib.types) submodule str attrsOf nullOr unspecified lazyAttrsOf;
   plaintextPrefix = "<PLAINTEXT>";
   plaintextNewlinePrefix = "<PLAINTEXT-NL>";
 
   sysConfig = config;
   secretPartType = secretName:
-    types.submodule ({config, ...}: {
-      options = with types; {
+    submodule ({config, ...}: {
+      options = {
         raw = mkOption {
           description = "Secret in fleet-specific undocumented format, do not use. Import from fleet.nix";
           internal = true;
@@ -49,11 +50,11 @@
         stablePath = mkOptionDefault "/run/secrets/${secretName}/${partName}";
       };
     });
-  secretType = types.submodule ({config, ...}: let
+  secretType = submodule ({config, ...}: let
     secretName = config._module.args.name;
   in {
-    freeformType = types.lazyAttrsOf (secretPartType secretName);
-    options = with types; {
+    freeformType = lazyAttrsOf (secretPartType secretName);
+    options = {
       shared = mkOption {
         description = "Is this secret owned by this machine, or propagated from shared secrets";
         default = false;
@@ -112,7 +113,7 @@
 in {
   options = {
     secrets = mkOption {
-      type = types.attrsOf secretType;
+      type = attrsOf secretType;
       default = {};
       description = "Host-local secrets";
     };