diff --git a/doc/manual/meson.build b/doc/manual/meson.build
index 28ff1f587..cfb6be36f 100644
--- a/doc/manual/meson.build
+++ b/doc/manual/meson.build
@@ -63,6 +63,7 @@ nix3_cli_json = custom_target(
   command : [ nix, '__dump-cli' ],
   capture : true,
   output : 'nix.json',
+  env : nix_env_for_docs,
 )
 
 generate_manual_deps = files(
diff --git a/doc/manual/src/command-ref/meson.build b/doc/manual/src/command-ref/meson.build
index 6405ce685..03d5f0a9c 100644
--- a/doc/manual/src/command-ref/meson.build
+++ b/doc/manual/src/command-ref/meson.build
@@ -62,4 +62,5 @@ conf_file_md = custom_target(
     experimental_features_shortlist_md,
   ],
   output : 'conf-file.md',
+  env : nix_env_for_docs,
 )