diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c0ec61d2..a4435fb9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -35,20 +35,20 @@ jobs:
     steps:
       - id: matrix
         name: build matrix
+        shell: python
         run: |
-          jq --version
-          QUERY='reduce .[] as $platform ([]; . += reduce $platform.policies.[] as $policy ([];. += [{policy: $policy, platform: $platform.platform, runner: $platform.runner}]))'
-          echo "${QUERY}"
-          JSON=$(cat << EOF | jq -c "${QUERY}"
-          [
-            {"platform": "x86_64", "runner": "ubuntu-22.04", "policies": ["manylinux2014", "manylinux_2_28", "manylinux_2_34", "musllinux_1_2"]},
-            {"platform": "aarch64", "runner": "ubuntu-22.04", "policies": ["manylinux2014", "manylinux_2_28", "manylinux_2_34", "musllinux_1_2"]},
-            {"platform": "i686", "runner": "ubuntu-22.04", "policies": ["manylinux2014", "musllinux_1_2"]},
-            {"platform": "armv7l", "runner": "ubuntu-22.04", "policies": ["manylinux_2_31", "musllinux_1_2"]}
+          import os
+          import json
+          reduced = [
+              ("x86_64", "ubuntu-22.04", ("manylinux2014", "manylinux_2_28", "manylinux_2_34", "musllinux_1_2")),
+              ("aarch64", "ubuntu-22.04", ("manylinux2014", "manylinux_2_28", "manylinux_2_34", "musllinux_1_2")),
+              ("i686", "ubuntu-22.04", ("manylinux2014", "musllinux_1_2")),
+              ("armv7l", "ubuntu-22.04", ("manylinux_2_31", "musllinux_1_2")),
           ]
-          EOF
-          )
-          echo "matrix=${JSON}" >> $GITHUB_OUTPUT
+          expanded = [{"policy": policy, "platform": platform, "runner": runner} for platform, runner, policies in reduced for policy in policies]
+          print(json.dumps(expanded, indent=2))
+          with open(os.environ["GITHUB_OUTPUT"], "at") as f:
+              f.write(f"matrix={json.dumps(expanded)}")
 
   build_manylinux:
     name: ${{ matrix.policy }}_${{ matrix.platform }}