diff --git a/coordinode/coordinode/client.py b/coordinode/coordinode/client.py
index 3c08685..68bf865 100644
--- a/coordinode/coordinode/client.py
+++ b/coordinode/coordinode/client.py
@@ -2011,9 +2011,10 @@ async def create_constraint(
                 returned with its running build, so a retry after a lost reply
                 does not start a second build.
             wait: Seconds to wait for the build of the owned index. ``None``:
-                the server's default. ``0``: return once the constraint and its
-                build are admitted. The call's deadline is extended by it, so
-                the deadline does not expire while the server is still waiting.
+                as long as the client's timeout. ``0``: return once the
+                constraint and its build are admitted. The call's deadline is
+                extended by it, so the deadline does not expire while the
+                server is still waiting.
         """
         from coordinode._proto.coordinode.v2.graph.schema_pb2 import (  # type: ignore[import]
             ConstraintKind,
@@ -2043,12 +2044,13 @@ async def create_constraint(
         )
         if property_type is not None:
             req.property_type.CopyFrom(self._property_type_proto(property_type, "the constraint"))
-        timeout = self._timeout
-        if wait is not None:
-            # A zero wait is sent too: absent takes the server's default.
-            req.wait.FromTimedelta(datetime.timedelta(seconds=wait))
-            timeout += wait
-        created = await self._schema_stub.CreateConstraint(req, timeout=timeout)
+        # Always sent: an absent wait takes the server's default, which this
+        # client cannot see and may exceed its deadline. Without one named,
+        # the server waits as long as this client's timeout.
+        if wait is None:
+            wait = self._timeout
+        req.wait.FromTimedelta(datetime.timedelta(seconds=wait))
+        created = await self._schema_stub.CreateConstraint(req, timeout=self._timeout + wait)
         return ConstraintInfo(created)
 
     async def drop_constraint(self, name: str, *, if_exists: bool = False) -> None:
diff --git a/tests/unit/test_schema_crud.py b/tests/unit/test_schema_crud.py
index bb33ef5..3dffa5f 100644
--- a/tests/unit/test_schema_crud.py
+++ b/tests/unit/test_schema_crud.py
@@ -411,8 +411,23 @@ async def _inner() -> None:
             assert (sent.name, sent.label, list(sent.properties)) == ("l_key", "L", ["a", "b"])
             assert sent.kind == schema_pb2.CONSTRAINT_KIND_NODE_KEY and sent.if_not_exists
             assert not sent.HasField("property_type")
-            # No wait named: the server's own default applies, so none is sent.
-            assert not sent.HasField("wait")
+
+        asyncio.run(_inner())
+
+    def test_default_wait_ends_before_the_deadline(self):
+        # With no wait named, the server's own default applies (60 s on
+        # 0.7.2, operator-tunable), longer than the client's 30 s timeout: a
+        # build between the two ended the call with DEADLINE_EXCEEDED while
+        # the server went on to create the constraint. The client's timeout
+        # is sent as the wait instead, and the deadline covers it.
+        async def _inner() -> None:
+            client = self._client()
+            await client.create_constraint("L", "email", "unique")
+            call = client._schema_stub.CreateConstraint.call_args
+            sent = call.args[0]
+            assert sent.HasField("wait")
+            assert sent.wait.ToTimedelta().total_seconds() == pytest.approx(client._timeout)
+            assert call.kwargs["timeout"] > client._timeout
 
         asyncio.run(_inner())