diff --git a/.github/workflows/nix_cache.yaml b/.github/workflows/nix_cache.yaml
index 2dffbfd6..967a5982 100644
--- a/.github/workflows/nix_cache.yaml
+++ b/.github/workflows/nix_cache.yaml
@@ -29,5 +29,6 @@ jobs:
         run: nix build .\#devShells.x86_64-linux.impure
       - name: Build impure devshell (CUDA dev)
         run: nix build .\#devShells.x86_64-linux.impureWithCuda
-      - name: Build pure devshell
-        run: nix build .\#devShells.x86_64-linux.pure
+      # Pure shell dependencies are covered by Nix tests.
+      # - name: Build pure devshell
+      #   run: nix build .\#devShells.x86_64-linux.pure
diff --git a/nix/server.nix b/nix/server.nix
index 5903a65a..237102a8 100644
--- a/nix/server.nix
+++ b/nix/server.nix
@@ -30,6 +30,7 @@
   opentelemetry-semantic-conventions,
   outlines,
   peft,
+  pillow,
   prometheus-client,
   punica-kernels,
   py-cpuinfo,
@@ -69,6 +70,7 @@ buildPythonPackage {
     "huggingface-hub"
     "loguru"
     "opentelemetry-instrumentation-grpc"
+    "pillow"
     "sentencepiece"
     "typer"
   ];
@@ -102,6 +104,7 @@ buildPythonPackage {
     opentelemetry-semantic-conventions
     outlines
     peft
+    pillow
     prometheus-client
     punica-kernels
     py-cpuinfo