diff --git a/skills/kugetsu/scripts/kugetsu b/skills/kugetsu/scripts/kugetsu
index 3e847d0..d293a3c 100755
--- a/skills/kugetsu/scripts/kugetsu
+++ b/skills/kugetsu/scripts/kugetsu
@@ -481,6 +481,13 @@ write_index() {
     local issues_json="$3"
     local temp_file="$INDEX_FILE.tmp.$$"
     printf '{"base": %s, "pm_agent": %s, "issues": %s}\n' "$base" "$pm_agent" "$issues_json" > "$temp_file"
+    
+    if ! python3 -c "import json; json.load(open('$temp_file'))" 2>/dev/null; then
+        echo "Error: write_index would create malformed JSON, aborting. base=$base, pm_agent=$pm_agent, issues_json=$issues_json" >&2
+        rm -f "$temp_file"
+        return 1
+    fi
+    
     mv "$temp_file" "$INDEX_FILE"
 }
 
diff --git a/skills/kugetsu/scripts/kugetsu-index.sh b/skills/kugetsu/scripts/kugetsu-index.sh
index 8eec8c2..f1e6695 100755
--- a/skills/kugetsu/scripts/kugetsu-index.sh
+++ b/skills/kugetsu/scripts/kugetsu-index.sh
@@ -15,6 +15,13 @@ write_index() {
     local issues_json="$3"
     local temp_file="$INDEX_FILE.tmp.$$"
     printf '{"base": %s, "pm_agent": %s, "issues": %s}\n' "$base" "$pm_agent" "$issues_json" > "$temp_file"
+    
+    if ! python3 -c "import json; json.load(open('$temp_file'))" 2>/dev/null; then
+        echo "Error: write_index would create malformed JSON, aborting. base=$base, pm_agent=$pm_agent, issues_json=$issues_json" >&2
+        rm -f "$temp_file"
+        return 1
+    fi
+    
     mv "$temp_file" "$INDEX_FILE"
 }