diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index e90ecc03..f645b45c 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -156,6 +156,8 @@ jobs:
           xcodebuild -scheme cmux -configuration Release -derivedDataPath build-arm \
             -destination 'platform=macOS,arch=arm64' \
             -clonedSourcePackagesDirPath .spm-cache \
+            ARCHS="arm64" \
+            ONLY_ACTIVE_ARCH=YES \
             CODE_SIGNING_ALLOWED=NO ASSETCATALOG_COMPILER_APPICON_NAME=AppIcon-Nightly build
 
       - name: Build universal app (Release)
@@ -167,15 +169,23 @@ jobs:
             ONLY_ACTIVE_ARCH=NO \
             CODE_SIGNING_ALLOWED=NO ASSETCATALOG_COMPILER_APPICON_NAME=AppIcon-Nightly build
 
-      - name: Verify universal binaries
+      - name: Verify nightly binary architectures
         run: |
           set -euo pipefail
+          ARM_APP_BINARY="build-arm/Build/Products/Release/cmux.app/Contents/MacOS/cmux"
+          ARM_CLI_BINARY="build-arm/Build/Products/Release/cmux.app/Contents/Resources/bin/cmux"
           APP_BINARY="build-universal/Build/Products/Release/cmux.app/Contents/MacOS/cmux"
           CLI_BINARY="build-universal/Build/Products/Release/cmux.app/Contents/Resources/bin/cmux"
+          ARM_APP_ARCHS="$(lipo -archs "$ARM_APP_BINARY")"
+          ARM_CLI_ARCHS="$(lipo -archs "$ARM_CLI_BINARY")"
           APP_ARCHS="$(lipo -archs "$APP_BINARY")"
           CLI_ARCHS="$(lipo -archs "$CLI_BINARY")"
+          echo "Arm app binary architectures: $ARM_APP_ARCHS"
+          echo "Arm CLI binary architectures: $ARM_CLI_ARCHS"
           echo "App binary architectures: $APP_ARCHS"
           echo "CLI binary architectures: $CLI_ARCHS"
+          [[ "$ARM_APP_ARCHS" == "arm64" ]]
+          [[ "$ARM_CLI_ARCHS" == "arm64" ]]
           [[ "$APP_ARCHS" == *arm64* && "$APP_ARCHS" == *x86_64* ]]
           [[ "$CLI_ARCHS" == *arm64* && "$CLI_ARCHS" == *x86_64* ]]
 
diff --git a/tests/test_nightly_universal_build.sh b/tests/test_nightly_universal_build.sh
index b6b9e63a..e86dbf36 100644
--- a/tests/test_nightly_universal_build.sh
+++ b/tests/test_nightly_universal_build.sh
@@ -11,25 +11,31 @@ if ! awk '
   in_arm && /^      - name:/ { in_arm=0 }
   in_universal && /^      - name:/ { in_universal=0 }
   in_arm && /-destination '\''platform=macOS,arch=arm64'\''/ { saw_arm_destination=1 }
+  in_arm && /ARCHS="arm64"/ { saw_arm_archs=1 }
+  in_arm && /ONLY_ACTIVE_ARCH=YES/ { saw_arm_only_active_arch=1 }
   in_universal && /-destination '\''generic\/platform=macOS'\''/ { saw_universal_destination=1 }
   in_universal && /ARCHS="arm64 x86_64"/ { saw_universal_archs=1 }
   in_universal && /ONLY_ACTIVE_ARCH=NO/ { saw_universal_only_active_arch=1 }
   END {
-    exit !(saw_arm_destination && saw_universal_destination && saw_universal_archs && saw_universal_only_active_arch)
+    exit !(saw_arm_destination && saw_arm_archs && saw_arm_only_active_arch && saw_universal_destination && saw_universal_archs && saw_universal_only_active_arch)
   }
 ' "$WORKFLOW_FILE"; then
-  echo "FAIL: nightly workflow must build both Apple Silicon and universal variants explicitly"
+  echo "FAIL: nightly workflow must force Apple Silicon nightly to arm64-only and universal nightly to both slices"
   exit 1
 fi
 
 if ! awk '
-  /^      - name: Verify universal binaries/ { in_verify=1; next }
+  /^      - name: Verify nightly binary architectures/ { in_verify=1; next }
   in_verify && /^      - name:/ { in_verify=0 }
+  in_verify && /lipo -archs "\$ARM_APP_BINARY"/ { saw_arm_app=1 }
+  in_verify && /lipo -archs "\$ARM_CLI_BINARY"/ { saw_arm_cli=1 }
   in_verify && /lipo -archs "\$APP_BINARY"/ { saw_app=1 }
   in_verify && /lipo -archs "\$CLI_BINARY"/ { saw_cli=1 }
-  END { exit !(saw_app && saw_cli) }
+  in_verify && /\[\[ "\$ARM_APP_ARCHS" == "arm64" \]\]/ { saw_arm_app_assert=1 }
+  in_verify && /\[\[ "\$ARM_CLI_ARCHS" == "arm64" \]\]/ { saw_arm_cli_assert=1 }
+  END { exit !(saw_arm_app && saw_arm_cli && saw_app && saw_cli && saw_arm_app_assert && saw_arm_cli_assert) }
 ' "$WORKFLOW_FILE"; then
-  echo "FAIL: nightly workflow must verify both app and CLI universal slices with lipo"
+  echo "FAIL: nightly workflow must verify arm-only and universal slices with lipo"
   exit 1
 fi