diff --git a/.github/workflows/main-stock-ubuntu.yml b/.github/workflows/main-stock-ubuntu.yml
index 7a92e3a9..c5543522 100644
--- a/.github/workflows/main-stock-ubuntu.yml
+++ b/.github/workflows/main-stock-ubuntu.yml
@@ -26,12 +26,16 @@ jobs:
           sudo apt update
           echo "::group::cmake install"
           sudo apt install -y cmake
+          echo "::endgroup"
           echo "::group::git install"
           sudo apt install -y git
+          echo "::endgroup"
           echo "::group::pybind11-dev install"
           sudo apt install -y pybind11-dev
+          echo "::endgroup"
           echo "::group::llvm18 install"
           sudo apt install -y llvm-18-dev
+          echo "::endgroup"
           #echo "::group::clang18 install"
           #sudo apt install -y clang-18
           #echo "::group::lldb18 install"
@@ -48,8 +52,10 @@ jobs:
           echo "::group::catch2 configure"
           mkdir .build
           cmake -B .build -S .
+          echo "::endgroup"
           echo "::group::catch2 install"
           sudo cmake --build .build --target install
+          echo "::endgroup"
 
           # this should be sufficient for find_package(Catch2) to work
 
@@ -63,10 +69,13 @@ jobs:
           mkdir -p ${PREFIX}
           echo "::group::xo-cmake configure"
           cmake -B .build0 -S xo-cmake -DCMAKE_INSTALL_PREFIX=${PREFIX}
+          echo "::endgroup"
           echo "::group::xo-cmake build"
           cmake --build .build0
+          echo "::endgroup"
           echo "::group::xo-cmake install"
           cmake --install .build0
+          echo "::endgroup"
 
       - name: build xo subprojects
         run: |
@@ -74,14 +83,17 @@ jobs:
           PATH=${{github.workspace}}/local/bin:${PATH}
           echo "::group::xo configure"
           cmake -B .build -S . -DCMAKE_INSTALL_PREFIX=${PREFIX} -DCMAKE_PREFIX_PATH=/usr/local # -DCMAKE_FIND_DEBUG_MODE=ON
+          echo "::endgroup"
 
           # note: xo-foo targets exist, but don't build anything
 
           echo "::group::xo build"
           cmake --build .build #--verbose
+          echo "::endgroup"
 
           echo "::group::xo install"
           cmake --install .build
+          echo "::endgroup"
 
       - name: print install path
         run: |
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e9a849a6..773d5115 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -84,7 +84,7 @@ add_subdirectory(xo-pyexpression)
 add_subdirectory(xo-tokenizer)
 add_subdirectory(xo-reader)
 add_subdirectory(xo-jit)
-#add_subdirectory(xo-pyjit)
+add_subdirectory(xo-pyjit)
 #add_subdirectory(xo-callback)
 #add_subdirectory(xo-webutil)
 #add_subdirectory(xo-pywebutil)
diff --git a/default.nix b/default.nix
index 938e2d4a..f3d02c30 100644
--- a/default.nix
+++ b/default.nix
@@ -60,7 +60,7 @@ let
           xo-jit            = self.callPackage pkgs/xo-jit.nix            { stdenv = customStdenv;
                                                                             clang = llvmPackages.clang;
                                                                             llvm = llvmPackages.llvm; };
-#          xo-pyjit          = self.callPackage pkgs/xo-pyjit.nix          {};
+          xo-pyjit          = self.callPackage pkgs/xo-pyjit.nix          {};
 #          xo-callback       = self.callPackage pkgs/xo-callback.nix       {};
 #          xo-webutil        = self.callPackage pkgs/xo-webutil.nix        {};
 #          xo-pywebutil      = self.callPackage pkgs/xo-pywebutil.nix      {};
diff --git a/pkgs/xo-pyjit.nix b/pkgs/xo-pyjit.nix
new file mode 100644
index 00000000..04633742
--- /dev/null
+++ b/pkgs/xo-pyjit.nix
@@ -0,0 +1,39 @@
+{
+  # nixpkgs dependencies
+  stdenv, cmake, catch2, # ... other deps here
+
+  # xo dependencies
+  xo-cmake, xo-pyutil, xo-jit,
+
+  xo-pyexpression,
+  #xo-pyreflect,
+
+  # args
+
+  #   attrset for fetching source code.
+  #    { type, owner, repo, ref }
+  #
+  #   e.g. type="github", owner="rconybea", repo="cmake-examples", ref="ex1b"
+  #
+  #   see [[../flake.nix]]
+  #
+  #cmake-examples-ex1-path
+
+  # someconfigurationoption ? false
+} :
+
+stdenv.mkDerivation (finalattrs:
+  {
+    name = "xo-pyjit";
+    version = "1.0";
+
+    src = ../xo-pyjit;
+
+    cmakeFlags = ["-DCMAKE_MODULE_PATH=${xo-cmake}/share/cmake"];
+    doCheck = true;
+    nativeBuildInputs = [ cmake catch2 xo-cmake ];
+    propagatedBuildInputs = [ xo-pyutil
+                              #xo-pyreflect
+                              xo-pyexpression
+                              xo-jit ];
+  })
diff --git a/pkgs/xo-userenv.nix b/pkgs/xo-userenv.nix
index bc3fb0fc..c7bdd032 100644
--- a/pkgs/xo-userenv.nix
+++ b/pkgs/xo-userenv.nix
@@ -53,7 +53,7 @@
   xo-tokenizer,
   xo-reader,
   xo-jit,
-#  xo-pyjit
+  xo-pyjit
 
   # other args