diff --git a/nix/devshell.nix b/nix/devshell.nix
index 9288558..f389f2b 100644
--- a/nix/devshell.nix
+++ b/nix/devshell.nix
@@ -19,6 +19,8 @@ let
     env = {
       UV_PYTHON = pythonSet.python.interpreter;
       UV_PYTHON_DOWNLOADS = "never";
+      UV_CONCURRENT_DOWNLOADS = "4";
+      UV_HTTP_TIMEOUT = "600";
     };
     shellHook = ''
       unset PYTHONPATH
@@ -38,23 +40,32 @@ let
       }
     );
 
+  driverLibs = lib.optionalString pkgs.stdenv.hostPlatform.isLinux "${pkgs.addDriverRunpath.driverLink}/lib";
+
   uv2nix = mkDevShell {
     packages = [ virtualenv ];
-    env.UV_NO_SYNC = "1";
+    env = {
+      UV_NO_SYNC = "1";
+    }
+    // lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux {
+      LD_LIBRARY_PATH = driverLibs;
+    };
   };
 
   impure = mkDevShell {
     packages = [ pythonSet.python ];
     env = lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux {
-      LD_LIBRARY_PATH = lib.makeLibraryPath [ pkgs.stdenv.cc.cc.lib ];
+      LD_LIBRARY_PATH = lib.makeLibraryPath [ pkgs.stdenv.cc.cc.lib ] + ":" + driverLibs;
     };
     shellHook = ''
-      uv sync
+      if [ ! -x .venv/bin/python ] || [ uv.lock -nt .venv/pyvenv.cfg ]; then
+        uv sync --frozen
+      fi
       . .venv/bin/activate
     '';
   };
 in
 {
   inherit impure uv2nix;
-  default = impure;
+  default = uv2nix;
 }
diff --git a/nix/python.nix b/nix/python.nix
index 1851a86..87aa3df 100644
--- a/nix/python.nix
+++ b/nix/python.nix
@@ -9,34 +9,53 @@ let
 
   pythonOverlay = workspace.mkPyprojectOverlay { sourcePreference = "wheel"; };
 
-  # sdist-only deps that build with setuptools but omit it from
-  # build-system.requires, so uv2nix has nothing to bootstrap them with.
-  needsSetuptools = [
-    "watchdog"
-  ];
+  packageOverrides = final: prev: {
+    # uv.lock omits build-system metadata required for this sdist build.
+    watchdog = prev.watchdog.overrideAttrs (old: {
+      nativeBuildInputs =
+        old.nativeBuildInputs
+        ++ final.resolveBuildSystem {
+          setuptools = [ ];
+        };
+    });
+  };
 
-  pythonOverrides =
-    final: prev:
-    lib.genAttrs needsSetuptools (
-      name:
-      prev.${name}.overrideAttrs (old: {
-        nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ [ final.setuptools ];
-      })
-    );
+  isCudaWheel =
+    name:
+    lib.hasPrefix "nvidia-" name
+    || builtins.elem name [
+      "torch"
+      "triton"
+    ];
+
+  cudaWheelOverrides =
+    _final: prev:
+    lib.mapAttrs (
+      _name: package:
+      package.overrideAttrs {
+        # Linux torch depends on CUDA libraries shipped by sibling wheels.
+        # autoPatchelf cannot resolve them across separate derivations.
+        autoPatchelfIgnoreMissingDeps = true;
+      }
+    ) (lib.filterAttrs (name: _package: isCudaWheel name) prev);
 in
 {
   inherit workspace;
 
   mkPythonSet =
     pkgs:
+    let
+      overlays = [
+        inputs.pyproject-build-systems.overlays.wheel
+        pythonOverlay
+        packageOverrides
+      ]
+      ++ lib.optionals pkgs.stdenv.hostPlatform.isLinux [
+        cudaWheelOverrides
+      ];
+    in
     (pkgs.callPackage inputs.pyproject-nix.build.packages {
       python = pkgs.python314;
     }).overrideScope
-      (
-        lib.composeManyExtensions [
-          inputs.pyproject-build-systems.overlays.wheel
-          pythonOverlay
-          pythonOverrides
-        ]
-      );
+      (lib.composeManyExtensions overlays);
 }