diff --git a/scripts/lint-agents.sh b/scripts/lint-agents.sh
index 086b386c..caf61571 100755
--- a/scripts/lint-agents.sh
+++ b/scripts/lint-agents.sh
@@ -112,6 +112,9 @@ lint_file() {
     if ! grep -qE -- "^${field}:" <<<"$frontmatter"; then
       echo "ERROR $file: missing frontmatter field '${field}'"
       errors=$((errors + 1))
+    elif [[ ! "$(get_field "$field" "$file")" =~ [^[:space:]] ]]; then
+      echo "ERROR $file: frontmatter field '${field}' must not be empty"
+      errors=$((errors + 1))
     fi
   done
 
diff --git a/scripts/test-convert-frontmatter.sh b/scripts/test-convert-frontmatter.sh
index 4162cd48..75df39ff 100755
--- a/scripts/test-convert-frontmatter.sh
+++ b/scripts/test-convert-frontmatter.sh
@@ -56,4 +56,28 @@ assert_quoted \
   "$OUTPUT_DIR/qwen/agents/programmatic-display-buyer.md" \
   tools
 
-echo "PASS: converted YAML frontmatter keeps scalar values safely quoted"
+# A present but empty required field is unusable discovery metadata. Check the
+# source linter directly, including YAML's quoted empty-string form.
+cat > "$OUTPUT_DIR/agent.md" <<'EOF'
+---
+name: Example Agent
+description: Builds useful examples
+color: red
+---
+
+## Identity
+
+## Core Mission
+
+## Critical Rules
+
+EOF
+for field in name description color; do
+  sed "s/^${field}:.*/${field}: \"\"/" "$OUTPUT_DIR/agent.md" > "$OUTPUT_DIR/empty-$field.md"
+  if "$SCRIPT_DIR/lint-agents.sh" "$OUTPUT_DIR/empty-$field.md" > /dev/null; then
+    printf 'Expected linter to reject empty %s metadata\n' "$field" >&2
+    exit 1
+  fi
+done
+
+echo "PASS: converted YAML frontmatter stays quoted and required source metadata is nonempty"
diff --git a/scripts/test-convert-outputs.sh b/scripts/test-convert-outputs.sh
index b198c96a..d8bd5718 100755
--- a/scripts/test-convert-outputs.sh
+++ b/scripts/test-convert-outputs.sh
@@ -199,8 +199,10 @@ src_bad = []
 for slug, (_gf_desc, _gf_name, path) in list(src.items()):
     try:
         data = frontmatter(open(os.path.join(R, path), encoding="utf-8").read())
-        assert isinstance(data, dict) and isinstance(data.get("name"), str) \
-            and isinstance(data.get("description"), str), "missing name/description"
+        assert isinstance(data, dict) and all(
+            isinstance(data.get(field), str) and data[field].strip()
+            for field in ("name", "description", "color")
+        ), "missing or empty name/description/color"
         assert data["description"][:1] not in ('"', "'"), "description starts with a quote character"
         src[slug] = (data["description"], data["name"], path)
     except Exception as e: