diff --git a/cmd/cue/cmd/testdata/script/cmd_execserialize.txtar b/cmd/cue/cmd/testdata/script/cmd_execserialize.txtar
new file mode 100644
index 000000000..ede79fd4e
--- /dev/null
+++ b/cmd/cue/cmd/testdata/script/cmd_execserialize.txtar
@@ -0,0 +1,31 @@
+! exec cue cmd printTask
+cmp stderr stderr.golden
+
+-- cue.mod/module.cue --
+module: "example.com"
+language: version: "v0.9.0"
+
+-- stderr.golden --
+command.printTask.print.text: invalid string argument: error in call to encoding/json.Marshal: cannot convert incomplete value "|((struct){\n}, (list){\n})" to JSON:
+    ./foo_tool.cue:14:2
+    ./foo_tool.cue:15:3
+    ./foo_tool.cue:15:9
+    tool/cli:5:3
+-- foo_tool.cue --
+package foo
+
+import (
+	"encoding/json"
+	"tool/cli"
+	"tool/exec"
+)
+
+command: printTask: {
+	task: exec.Run & {
+		cmd: ["true"]
+		stdout: string
+	}
+	print: cli.Print & {
+		text: json.Marshal(task)
+	}
+}