diff --git a/scripts/ci-update-coverage-badge.sh b/scripts/ci-update-coverage-badge.sh
index a3ca23e..b15f70b 100755
--- a/scripts/ci-update-coverage-badge.sh
+++ b/scripts/ci-update-coverage-badge.sh
@@ -40,18 +40,29 @@ if grep -q "${BADGE_TYPE}_Coverage-${COVERAGE}%" README.md || grep -q "coverage-
     exit 0
 fi
 
+# Cross-platform sed command
+# Detect if we're on macOS (BSD sed) or Linux (GNU sed)
+SED_CMD=""
+if [[ "$(uname)" == "Darwin" ]]; then
+    # macOS - requires empty string after -i
+    SED_CMD="sed -i ''"
+else
+    # Linux - standard GNU sed
+    SED_CMD="sed -i"
+fi
+
 # Update README - handle both old and new badge formats
 if [ "$BADGE_TYPE" = "bdd" ] || [ "$BADGE_TYPE" = "unit" ]; then
     # For BDD/Unit badges, add them if they don't exist, or update if they do
     if grep -q "${BADGE_TYPE}_Coverage" README.md; then
-        sed -i "s|https://img.shields.io/badge/${BADGE_TYPE}_Coverage-.*-.*?style=flat-square|${BADGE_URL}|" README.md
+        $SED_CMD "s|https://img.shields.io/badge/${BADGE_TYPE}_Coverage-.*-.*?style=flat-square|${BADGE_URL}|" README.md
     else
         # Add new badge line after the main coverage badge
-        sed -i "/coverage-.*-.*?style=flat-square/a\\n${BADGE_URL}" README.md
+        $SED_CMD "/coverage-.*-.*?style=flat-square/a\\n${BADGE_URL}" README.md
     fi
 else
     # For combined coverage, use the original logic
-    sed -i "s|https://img.shields.io/badge/coverage-.*-.*?style=flat-square|${BADGE_URL}|" README.md
+    $SED_CMD "s|https://img.shields.io/badge/coverage-.*-.*?style=flat-square|${BADGE_URL}|" README.md
 fi
 
 # Set up git