diff --git a/internal/engine/duckdb/crossrepo_contract_test.go b/internal/engine/duckdb/crossrepo_contract_test.go
new file mode 100644
index 000000000..07c441113
--- /dev/null
+++ b/internal/engine/duckdb/crossrepo_contract_test.go
@@ -0,0 +1,19 @@
+package duckdb
+
+import (
+	"strings"
+	"testing"
+)
+
+// The DuckDB adapter consumes darkwing's parser and AST. A quoted COLLATE
+// name is accepted only by darkwing's hardened transformer and must survive
+// conversion into sqlc's statement AST.
+func TestCrossRepoDuckDBCollateContract(t *testing.T) {
+	statements, err := NewParser().Parse(strings.NewReader("SELECT 'x' COLLATE 'nocase';"))
+	if err != nil {
+		t.Fatalf("DuckDB query should parse through the darkwing adapter: %v", err)
+	}
+	if len(statements) != 1 {
+		t.Fatalf("expected one converted statement, got %d", len(statements))
+	}
+}