diff --git a/.github/workflows/layers_partition_balance.yml b/.github/workflows/layers_partition_balance.yml
index abd23c42f08..76cc6a581fd 100644
--- a/.github/workflows/layers_partition_balance.yml
+++ b/.github/workflows/layers_partition_balance.yml
@@ -154,6 +154,7 @@ jobs:
           for (( VERSION=START_VERSION; VERSION<=END_VERSION; VERSION++ )); do
             NAME="${LAYER}-${ARCHITECTURE}"
             METADATA="source/${VERSION}.json"
+            POLICY="source/${VERSION}.policy.json"
             ZIP="source/${VERSION}.zip"
 
             aws --region us-east-1 lambda get-layer-version-by-arn \
@@ -162,6 +163,17 @@ jobs:
             LOCATION=$(jq -r '.Content.Location' "$METADATA")
             curl --fail --location --retry 3 --retry-delay 2 --output "$ZIP" "$LOCATION"
 
+            if ! aws --region us-east-1 lambda get-layer-version-policy \
+              --layer-name "arn:aws:lambda:us-east-1:017000801446:layer:${NAME}" \
+              --version-number "$VERSION" > "$POLICY" 2> policy-error.txt; then
+              if grep -q ResourceNotFoundException policy-error.txt; then
+                echo '{"Policy":null}' > "$POLICY"
+              else
+                cat policy-error.txt
+                exit 1
+              fi
+            fi
+
             EXPECTED_SHA=$(jq -r '.Content.CodeSha256' "$METADATA")
             ACTUAL_SHA=$(openssl dgst -sha256 -binary "$ZIP" | openssl enc -base64)
             if [[ "$ACTUAL_SHA" != "$EXPECTED_SHA" ]]; then
@@ -250,15 +262,26 @@ jobs:
           mkdir -p target
 
           has_public_permission() {
-            jq -e '
+            local result
+
+            if jq -e '
               (.Policy | if type == "string" then fromjson else . end)
               | any(.Statement[]?;
-                  .Sid == "PublicLayer"
-                  and .Effect == "Allow"
-                  and ((.Action | if type == "array" then . else [.] end) | index("lambda:GetLayerVersion") != null)
+                  .Effect == "Allow"
+                  and ((.Action // [] | if type == "array" then . else [.] end) | any(. == "*" or . == "lambda:*" or . == "lambda:GetLayerVersion"))
                   and (((.Principal | if type == "object" then .AWS // "" else . end) | if type == "array" then . else [.] end) | index("*") != null)
+                  and ((.Condition // {}) | length == 0)
                 )
-            ' "$1" > /dev/null
+            ' "$1" > /dev/null; then
+              return 0
+            else
+              result=$?
+              if (( result > 1 )); then
+                echo "Unable to evaluate layer policy $1 (jq exit ${result})"
+                exit 1
+              fi
+              return 1
+            fi
           }
 
           if ! aws --region "$REGION" lambda list-layer-versions \
@@ -276,6 +299,7 @@ jobs:
 
           for (( VERSION=START_VERSION; VERSION<=END_VERSION; VERSION++ )); do
             METADATA="source/${VERSION}.json"
+            SOURCE_POLICY="source/${VERSION}.policy.json"
             ZIP="source/${VERSION}.zip"
             TARGET_METADATA="target/${VERSION}.json"
             TARGET_ARN="arn:${PARTITION}:lambda:${REGION}:${AWS_ACCOUNT}:layer:${NAME}:${VERSION}"
@@ -313,6 +337,12 @@ jobs:
               exit 1
             fi
 
+            SOURCE_IS_PUBLIC=false
+            if has_public_permission "$SOURCE_POLICY"; then
+              SOURCE_IS_PUBLIC=true
+            fi
+            echo "Commercial source ${NAME}:${VERSION} public: ${SOURCE_IS_PUBLIC}"
+
             if [[ "$VERSION_EXISTS" == "true" ]]; then
               echo "${NAME}:${VERSION} already exists in ${REGION} with the expected SHA"
             else
@@ -323,13 +353,21 @@ jobs:
               fi
             fi
 
+            if [[ "$SOURCE_IS_PUBLIC" == "false" ]] && [[ "$HAS_PUBLIC_PERMISSION" == "true" ]]; then
+              echo "${NAME}:${VERSION} in ${REGION} is public but its commercial source is private"
+              exit 1
+            fi
+
             if [[ "$DRY_RUN" != "false" ]]; then
               if [[ "$VERSION_EXISTS" == "false" ]]; then
                 echo "Would publish ${NAME}:${VERSION} to ${REGION}"
                 CURRENT_POSITION=$VERSION
-              elif [[ "$HAS_PUBLIC_PERMISSION" == "false" ]]; then
+              elif [[ "$SOURCE_IS_PUBLIC" == "true" ]] && [[ "$HAS_PUBLIC_PERMISSION" == "false" ]]; then
                 echo "Would add public permission to ${NAME}:${VERSION} in ${REGION}"
               fi
+              if [[ "$SOURCE_IS_PUBLIC" == "false" ]]; then
+                echo "Would keep ${NAME}:${VERSION} private in ${REGION}"
+              fi
               continue
             fi
 
@@ -352,7 +390,7 @@ jobs:
               CURRENT_POSITION=$PUBLISHED_VERSION
             fi
 
-            if [[ "$HAS_PUBLIC_PERMISSION" == "false" ]]; then
+            if [[ "$SOURCE_IS_PUBLIC" == "true" ]] && [[ "$HAS_PUBLIC_PERMISSION" == "false" ]]; then
               if ! aws --region "$REGION" lambda add-layer-version-permission \
                 --layer-name "$NAME" \
                 --statement-id PublicLayer \
@@ -375,11 +413,24 @@ jobs:
               exit 1
             fi
 
-            aws --region "$REGION" lambda get-layer-version-policy \
+            if ! aws --region "$REGION" lambda get-layer-version-policy \
               --layer-name "$NAME" \
-              --version-number "$VERSION" > scratch/policy.json
-            if ! has_public_permission scratch/policy.json; then
-              echo "${NAME}:${VERSION} in ${REGION} is missing the expected public permission"
+              --version-number "$VERSION" > scratch/policy.json 2> scratch/policy-error.txt; then
+              if grep -q ResourceNotFoundException scratch/policy-error.txt; then
+                echo '{"Policy":null}' > scratch/policy.json
+              else
+                cat scratch/policy-error.txt
+                exit 1
+              fi
+            fi
+
+            TARGET_IS_PUBLIC=false
+            if has_public_permission scratch/policy.json; then
+              TARGET_IS_PUBLIC=true
+            fi
+
+            if [[ "$TARGET_IS_PUBLIC" != "$SOURCE_IS_PUBLIC" ]]; then
+              echo "${NAME}:${VERSION} in ${REGION} does not match its commercial source visibility"
               exit 1
             fi
           done
diff --git a/.github/workflows/layers_partitions.yml b/.github/workflows/layers_partitions.yml
index 65b80f30748..55492733625 100644
--- a/.github/workflows/layers_partitions.yml
+++ b/.github/workflows/layers_partitions.yml
@@ -98,6 +98,21 @@ jobs:
         run: |
           aws --region us-east-1 lambda get-layer-version-by-arn --arn arn:aws:lambda:us-east-1:017000801446:layer:${{ matrix.layer }}-${{ matrix.arch }}:${{ inputs.version }} --query 'Content.Location' | xargs curl -L -o ${{ matrix.layer }}-${{ matrix.arch }}.zip
           aws --region us-east-1 lambda get-layer-version-by-arn --arn arn:aws:lambda:us-east-1:017000801446:layer:${{ matrix.layer }}-${{ matrix.arch }}:${{ inputs.version }} > ${{ matrix.layer }}-${{ matrix.arch }}.json
+      - name: Grab Policy
+        env:
+          LAYER_NAME: ${{ matrix.layer }}-${{ matrix.arch }}
+          VERSION: ${{ inputs.version }}
+        run: |
+          if ! aws --region us-east-1 lambda get-layer-version-policy \
+            --layer-name "arn:aws:lambda:us-east-1:017000801446:layer:${LAYER_NAME}" \
+            --version-number "$VERSION" > "${LAYER_NAME}.policy.json" 2> policy-error.txt; then
+            if grep -q ResourceNotFoundException policy-error.txt; then
+              echo '{"Policy":null}' > "${LAYER_NAME}.policy.json"
+            else
+              cat policy-error.txt
+              exit 1
+            fi
+          fi
       - name: Store Zip
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
@@ -112,6 +127,13 @@ jobs:
           path: ${{ matrix.layer }}-${{ matrix.arch }}.json
           retention-days: 1
           if-no-files-found: error
+      - name: Store Policy
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: ${{ matrix.layer }}-${{ matrix.arch }}.policy.json
+          path: ${{ matrix.layer }}-${{ matrix.arch }}.policy.json
+          retention-days: 1
+          if-no-files-found: error
 
   copy:
     name: Copy
@@ -146,10 +168,37 @@ jobs:
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: ${{ matrix.layer }}-${{ matrix.arch }}.json
+      - name: Download Policy
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          name: ${{ matrix.layer }}-${{ matrix.arch }}.policy.json
       - name: Verify Layer Signature
         run: |
           SHA=$(jq -r '.Content.CodeSha256' '${{ matrix.layer }}-${{ matrix.arch }}.json')
           test "$(openssl dgst -sha256 -binary ${{ matrix.layer }}-${{ matrix.arch }}.zip | openssl enc -base64)" == "$SHA" && echo "SHA OK: ${SHA}" || exit 1
+      - id: source_policy
+        name: Source Layer Visibility
+        run: |
+          if jq -e '
+            (.Policy | if type == "string" then fromjson else . end)
+            | any(.Statement[]?;
+                .Effect == "Allow"
+                and ((.Action // [] | if type == "array" then . else [.] end) | any(. == "*" or . == "lambda:*" or . == "lambda:GetLayerVersion"))
+                and (((.Principal | if type == "object" then .AWS // "" else . end) | if type == "array" then . else [.] end) | index("*") != null)
+                and ((.Condition // {}) | length == 0)
+              )
+          ' '${{ matrix.layer }}-${{ matrix.arch }}.policy.json' > /dev/null; then
+            echo 'public=true' >> "$GITHUB_OUTPUT"
+            echo 'Commercial source layer is public'
+          else
+            RESULT=$?
+            if (( RESULT > 1 )); then
+              echo "Unable to evaluate source layer policy (jq exit ${RESULT})"
+              exit 1
+            fi
+            echo 'public=false' >> "$GITHUB_OUTPUT"
+            echo 'Commercial source layer is private'
+          fi
       - id: transform
         run: |
           echo 'CONVERTED_REGION=${{ matrix.region }}' | tr 'a-z\-' 'A-Z_' >> "$GITHUB_OUTPUT"
@@ -160,8 +209,29 @@ jobs:
           aws-region: ${{ matrix.region}}
           mask-aws-account-id: true
           audience: ${{ needs.setup.outputs.aud }}
+      - name: Validate target account
+        env:
+          AWS_ACCOUNT: ${{ secrets[format('AWS_ACCOUNT_{0}', steps.transform.outputs.CONVERTED_REGION)] }}
+          PARTITION: ${{ needs.setup.outputs.partition }}
+          REGION: ${{ matrix.region }}
+        run: |
+          if [[ ! "$AWS_ACCOUNT" =~ ^[0-9]{12}$ ]]; then
+            echo "AWS account secret for ${REGION} is missing or invalid"
+            exit 1
+          fi
+
+          CALLER_ACCOUNT=$(aws --region "$REGION" sts get-caller-identity --query Account --output text)
+          CALLER_ARN=$(aws --region "$REGION" sts get-caller-identity --query Arn --output text)
+
+          if [[ "$CALLER_ACCOUNT" != "$AWS_ACCOUNT" ]] || [[ "$CALLER_ARN" != "arn:${PARTITION}:"* ]]; then
+            echo "Assumed role does not match the expected account and partition for ${REGION}"
+            exit 1
+          fi
       - name: Create Layer
         id: create-layer
+        env:
+          SOURCE_IS_PUBLIC: ${{ steps.source_policy.outputs.public }}
+          VERSION: ${{ inputs.version }}
         run: |
           jq '{"LayerName": "${{ matrix.layer }}-${{ matrix.arch }}", "Description": .Description, "CompatibleRuntimes": .CompatibleRuntimes, "CompatibleArchitectures": .CompatibleArchitectures, "LicenseInfo": .LicenseInfo} | with_entries(select(.value != null))' '${{ matrix.layer }}-${{ matrix.arch }}.json' > input.json
 
@@ -171,17 +241,25 @@ jobs:
             --query 'Version' \
             --output text)
 
+          if (( LAYER_VERSION != VERSION )); then
+            echo "Expected to publish as version ${VERSION}, received ${LAYER_VERSION}"
+            exit 1
+          fi
+
           echo "LAYER_VERSION=$LAYER_VERSION" >> "$GITHUB_OUTPUT"
 
-          aws --region ${{ matrix.region}} lambda add-layer-version-permission \
-            --layer-name ${{ matrix.layer }}-${{ matrix.arch }} \
-            --statement-id 'PublicLayer' \
-            --action lambda:GetLayerVersion \
-            --principal '*' \
-            --version-number "$LAYER_VERSION"
+          if [[ "$SOURCE_IS_PUBLIC" == "true" ]]; then
+            aws --region ${{ matrix.region}} lambda add-layer-version-permission \
+              --layer-name ${{ matrix.layer }}-${{ matrix.arch }} \
+              --statement-id 'PublicLayer' \
+              --action lambda:GetLayerVersion \
+              --principal '*' \
+              --version-number "$LAYER_VERSION"
+          fi
       - name: Verify Layer
         env:
           LAYER_VERSION: ${{ steps.create-layer.outputs.LAYER_VERSION }}
+          SOURCE_IS_PUBLIC: ${{ steps.source_policy.outputs.public }}
         run: |
           export layer_output='${{ matrix.layer }}-${{ matrix.arch }}-${{matrix.region}}.json'
           aws --region ${{ matrix.region}} lambda get-layer-version-by-arn --arn 'arn:${{ needs.setup.outputs.partition }}:lambda:${{ matrix.region}}:${{ secrets[format('AWS_ACCOUNT_{0}', steps.transform.outputs.CONVERTED_REGION)] }}:layer:${{ matrix.layer }}-${{ matrix.arch }}:${{ env.LAYER_VERSION }}' > $layer_output
@@ -190,6 +268,41 @@ jobs:
           test "$REMOTE_SHA" == "$LOCAL_SHA" && echo "SHA OK: ${LOCAL_SHA}" || exit 1
           jq -s -r '["Layer Arn", "Runtimes", "Version", "Description", "SHA256"], ([.[0], .[1]] | .[] | [.LayerArn, (.CompatibleRuntimes | join("/")), .Version, .Description, .Content.CodeSha256]) |@tsv' '${{ matrix.layer }}-${{ matrix.arch }}.json' $layer_output | column -t -s $'\t'
 
+          if ! aws --region ${{ matrix.region}} lambda get-layer-version-policy \
+            --layer-name '${{ matrix.layer }}-${{ matrix.arch }}' \
+            --version-number "$LAYER_VERSION" > target-policy.json 2> policy-error.txt; then
+            if grep -q ResourceNotFoundException policy-error.txt; then
+              echo '{"Policy":null}' > target-policy.json
+            else
+              cat policy-error.txt
+              exit 1
+            fi
+          fi
+
+          TARGET_IS_PUBLIC=false
+          if jq -e '
+            (.Policy | if type == "string" then fromjson else . end)
+            | any(.Statement[]?;
+                .Effect == "Allow"
+                and ((.Action // [] | if type == "array" then . else [.] end) | any(. == "*" or . == "lambda:*" or . == "lambda:GetLayerVersion"))
+                and (((.Principal | if type == "object" then .AWS // "" else . end) | if type == "array" then . else [.] end) | index("*") != null)
+                and ((.Condition // {}) | length == 0)
+              )
+          ' target-policy.json > /dev/null; then
+            TARGET_IS_PUBLIC=true
+          else
+            RESULT=$?
+            if (( RESULT > 1 )); then
+              echo "Unable to evaluate target layer policy (jq exit ${RESULT})"
+              exit 1
+            fi
+          fi
+
+          if [[ "$TARGET_IS_PUBLIC" != "$SOURCE_IS_PUBLIC" ]]; then
+            echo "Published layer visibility does not match its commercial source"
+            exit 1
+          fi
+
       - name: Store Metadata - ${{ matrix.region }}
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with: