diff --git a/doc/doc-support/default.nix b/doc/doc-support/default.nix
index bea3e12a70b3..67195a4a58b0 100644
--- a/doc/doc-support/default.nix
+++ b/doc/doc-support/default.nix
@@ -45,7 +45,10 @@ let
   # NB: This file describes the Nixpkgs manual, which happens to use module
   #     docs infra originally developed for NixOS.
   optionsDoc = pkgs.nixosOptionsDoc {
-    inherit (pkgs.lib.evalModules { modules = [ ../../pkgs/top-level/config.nix ]; }) options;
+    inherit (pkgs.lib.evalModules {
+      modules = [ ../../pkgs/top-level/config.nix ];
+      specialArgs.class = "nixpkgsConfig";
+    }) options;
     documentType = "none";
     transformOptions = opt:
       opt // {
diff --git a/nixos/lib/eval-cacheable-options.nix b/nixos/lib/eval-cacheable-options.nix
index c3ba2ce66375..d26967ebe09b 100644
--- a/nixos/lib/eval-cacheable-options.nix
+++ b/nixos/lib/eval-cacheable-options.nix
@@ -33,6 +33,7 @@ let
     ];
     specialArgs = {
       inherit config pkgs utils;
+      class = "nixos";
     };
   };
   docs = import "${nixosPath}/doc/manual" {
diff --git a/nixos/lib/eval-config-minimal.nix b/nixos/lib/eval-config-minimal.nix
index d45b9ffd4261..7e28f4305127 100644
--- a/nixos/lib/eval-config-minimal.nix
+++ b/nixos/lib/eval-config-minimal.nix
@@ -40,7 +40,9 @@ let
     inherit prefix modules;
     specialArgs = {
       modulesPath = builtins.toString ../modules;
-    } // specialArgs;
+    } // specialArgs // {
+      class = "nixos";
+    };
   };
 
 in
diff --git a/nixos/lib/testing/default.nix b/nixos/lib/testing/default.nix
index 9d4f9dbc43d7..1bd6278ce684 100644
--- a/nixos/lib/testing/default.nix
+++ b/nixos/lib/testing/default.nix
@@ -1,7 +1,10 @@
 { lib }:
 let
 
-  evalTest = module: lib.evalModules { modules = testModules ++ [ module ]; };
+  evalTest = module: lib.evalModules {
+    modules = testModules ++ [ module ];
+    specialArgs.class = "nixosTest";
+  };
   runTest = module: (evalTest ({ config, ... }: { imports = [ module ]; result = config.test; })).config.result;
 
   testModules = [
diff --git a/nixos/modules/misc/documentation.nix b/nixos/modules/misc/documentation.nix
index e0c6af4abe10..1821dd866cb1 100644
--- a/nixos/modules/misc/documentation.nix
+++ b/nixos/modules/misc/documentation.nix
@@ -39,6 +39,7 @@ let
             _module.check = false;
           } ] ++ docModules.eager;
           specialArgs = specialArgs // {
+            class = "nixos";
             pkgs = scrubDerivations "pkgs" pkgs;
             # allow access to arbitrary options for eager modules, eg for getting
             # option types from lazy modules
diff --git a/pkgs/top-level/default.nix b/pkgs/top-level/default.nix
index b32aabc3a1fd..f54ce84aedad 100644
--- a/pkgs/top-level/default.nix
+++ b/pkgs/top-level/default.nix
@@ -82,6 +82,7 @@ in let
         config = config1;
       })
     ];
+    specialArgs.class = "nixpkgsConfig";
   };
 
   # take all the rest as-is