diff --git a/jupyter_ydoc/ystdin.py b/jupyter_ydoc/ystdin.py
index 514dc7a..9b451b9 100644
--- a/jupyter_ydoc/ystdin.py
+++ b/jupyter_ydoc/ystdin.py
@@ -1,36 +1,39 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+from uuid import uuid4
+
 from pycrdt import Map, Text
 
 
-def add_stdin(cell: Map, prompt: str = "", password: bool = False) -> None:
+def add_stdin(cell: Map, prompt: str = "", password: bool = False) -> str:
     """
-    Adds an stdin Map in the cell outputs.
+    Adds an stdin Map in the cell outputs, and returns its ID.
 
     Schema:
 
     .. code-block:: json
 
         {
-            "state": Map[
-                "pending": bool,
-                "password": bool
-            ],
+            "output_type": "stdin",
+            "id": str,
+            "submitted": bool,
+            "password": bool
             "prompt": str,
             "input": Text
         }
     """
+    idx = uuid4().hex
     stdin = Map(
         {
             "output_type": "stdin",
-            "state": {
-                "pending": True,
-                "password": password,
-            },
+            "id": idx,
+            "submitted": False,
+            "password": password,
             "prompt": prompt,
             "input": Text(),
         }
     )
     outputs = cell.get("outputs")
     outputs.append(stdin)
+    return idx
diff --git a/tests/test_ydocs.py b/tests/test_ydocs.py
index e003dc5..6138e65 100644
--- a/tests/test_ydocs.py
+++ b/tests/test_ydocs.py
@@ -12,7 +12,6 @@ def test_yblob():
     changes = []
 
     def callback(topic, event):
-        print(topic, event)
         changes.append((topic, event))
 
     yblob.observe(callback)
@@ -33,20 +32,22 @@ def test_stdin():
         }
     )
     ycell = ynotebook.ycells[0]
-    add_stdin(ycell)
+    add_stdin(ycell, prompt="pwd:", password=True)
+    stdin = ycell["outputs"][0]["input"]
+    stdin += "mypassword"
     cell = ycell.to_py()
     # cell ID is random, ignore that
     del cell["id"]
+    # input ID is random, ignore that
+    del cell["outputs"][0]["id"]
     assert cell == {
         "outputs": [
             {
                 "output_type": "stdin",
-                "input": "",
-                "prompt": "",
-                "state": {
-                    "password": False,
-                    "pending": True,
-                },
+                "input": "mypassword",
+                "prompt": "pwd:",
+                "password": True,
+                "submitted": False,
             }
         ],
         "source": "",