diff --git a/packages/cultnet-py/tests/test_raw_record_stamp.py b/packages/cultnet-py/tests/test_raw_record_stamp.py
new file mode 100644
index 00000000..d6e6cba6
--- /dev/null
+++ b/packages/cultnet-py/tests/test_raw_record_stamp.py
@@ -0,0 +1,57 @@
+"""raw_record_to_envelope is the one place a replicated raw record becomes an envelope; it refuses a record whose storedAt is no stamp.
+
+The stamp shape is tests/vectors/stored-at-stamp/stamps.msgpack (variants:ruling:raw-put-without-stamp-refused); cultmesh-py tests the
+whole replication paths, this tests the function itself.
+"""
+
+from __future__ import annotations
+
+import unittest
+from pathlib import Path
+from typing import Any
+
+import msgpack
+from cultcache_py import define_database_entry_type
+from cultnet_py.replication import raw_record_to_envelope
+
+VECTOR = Path(__file__).resolve().parents[3] / "tests/vectors/stored-at-stamp/stamps.msgpack"
+ROWS: list[tuple[str, bool]] = [(text, parses) for text, parses in msgpack.unpackb(VECTOR.read_bytes(), raw=False)]
+NOTE = define_database_entry_type(
+    "tests.envelope_note",
+    [("schema_version", 0), ("text", 1)],
+    schema_id="sha256:envelope-note",
+    schema_name="tests.envelope_note",
+    schema_version="tests.envelope_note.v1",
+)
+
+
+def record_with(stamp: Any) -> dict[str, Any]:
+    record = {
+        "schemaId": "sha256:envelope-note",
+        "recordKey": "note:1",
+        "payload": NOTE.encode_payload({"schema_version": "tests.envelope_note.v1", "text": "t"}),
+    }
+    if stamp is not None:
+        record["storedAt"] = stamp
+    return record
+
+
+class RawRecordToEnvelopeStampTests(unittest.TestCase):
+    def test_every_vector_row_is_an_envelope_or_a_refusal_as_the_vector_says(self) -> None:
+        self.assertGreater(len(ROWS), 30)
+        for text, parses in ROWS:
+            with self.subTest(text=text):
+                if parses:
+                    self.assertEqual(raw_record_to_envelope(NOTE, "sha256:envelope-note", record_with(text)).stored_at, text)
+                else:
+                    with self.assertRaises(ValueError):
+                        raw_record_to_envelope(NOTE, "sha256:envelope-note", record_with(text))
+
+    def test_a_missing_or_non_string_stamp_is_refused(self) -> None:
+        for stamp in (None, 12345, b"2026-11-07T00:00:00Z"):
+            with self.subTest(stamp=stamp), self.assertRaises(ValueError):
+                raw_record_to_envelope(NOTE, "sha256:envelope-note", record_with(stamp))
+
+
+if __name__ == "__main__":
+    unittest.main()