try 2

.gitignore

@@ -1,3 +1 @@
 /result
-# we ignore flake.lock because this isn't intended to pin a specific version of nixpkgs
-/flake.lock

default.nix

@@ -1,5 +1,22 @@
-{ ... }:
-{
-  imports = [ ./module.nix ];
-  nixpkgs.overlays = import ./overlay.nix;
-}
+let
+  lockFile = builtins.fromJSON (builtins.readFile ./flake.lock);
+  nixpkgs = builtins.fetchTarball {
+    url = "";
+    sha256 = lockFile.nodes.nixpkgs.locked.narHash;
+  };
+  lix = builtins.fetchTarball {
+    url = "";
+    sha256 = lockFile.nodes.lix.locked.narHash;
+  };
+  lix-module = builtins.fetchTarball {
+    url = "";
+    sha256 = lockFile.nodes.lix-module.locked.narHash;
+  };
+in
+args: 
+  import "${nixpkgs}" {
+    overlays = [
+      (import ./overlay.nix)
+      (import "${lix-module}/overlay.nix" { inherit lix; })
+    ] ++ args.overlays;
+  } // (builtins.removeAttrs args [ "overlays" ])

flake.lock

@@ -0,0 +1,57 @@
+{
+  "nodes": {
+    "lix": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1723503926,
+        "narHash": "sha256-Rosl9iA9MybF5Bud4BTAQ9adbY81aGmPfV8dDBGl34s=",
+        "rev": "bcaeb6388b8916ac6d1736e3aa2b13313e6a6bd2",
+        "type": "tarball",
+        "url": "https://git.lix.systems/api/v1/repos/lix-project/lix/archive/bcaeb6388b8916ac6d1736e3aa2b13313e6a6bd2.tar.gz?rev=bcaeb6388b8916ac6d1736e3aa2b13313e6a6bd2"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://git.lix.systems/lix-project/lix/archive/2.91.0.tar.gz"
+      }
+    },
+    "lix-module": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1723510904,
+        "narHash": "sha256-zNW/rqNJwhq2lYmQf19wJerRuNimjhxHKmzrWWFJYts=",
+        "rev": "622a2253a071a1fb97a4d3c8103a91114acc1140",
+        "type": "tarball",
+        "url": "https://git.lix.systems/api/v1/repos/lix-project/nixos-module/archive/622a2253a071a1fb97a4d3c8103a91114acc1140.tar.gz?rev=622a2253a071a1fb97a4d3c8103a91114acc1140"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://git.lix.systems/lix-project/nixos-module/archive/2.91.0.tar.gz"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1729256560,
+        "narHash": "sha256-/uilDXvCIEs3C9l73JTACm4quuHUsIHcns1c+cHUJwA=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "4c2fcb090b1f3e5b47eaa7bd33913b574a11e0a0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "lix": "lix",
+        "lix-module": "lix-module",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -2,6 +2,8 @@
   description = "dragnpkgs together with nixpkgs and lix";
 
   inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
     lix-module = {
       url = "https://git.lix.systems/lix-project/nixos-module/archive/2.91.0.tar.gz";
       flake = false;