diff --git a/tests/test_python_patterns.py b/tests/test_python_patterns.py
index 329813e..f86416a 100644
--- a/tests/test_python_patterns.py
+++ b/tests/test_python_patterns.py
@@ -7,6 +7,7 @@
 These tests run without a live database — all external calls are mocked.
 """
 import ast
+import glob
 import inspect
 import re
 import textwrap
@@ -120,3 +121,64 @@ def test_tracks_failures(self):
             "rollup_refresh.py should track failures"
         assert "failures.append" in source, \
             "rollup_refresh.py should append to failures list"
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# Schema-drift guard
+# ─────────────────────────────────────────────────────────────────────────────
+
+WORKFLOW_GLOB = "databricks/workflows/*.py"
+SQL_GLOB = "sql/*.sql"
+
+# `lakets.<object>` references in Python (registries, functions used in SQL).
+_LAKETS_REF = re.compile(r"\blakets\.([a-zA-Z_][a-zA-Z0-9_]*)")
+# Logger names like getLogger("lakets.partition_manager") are not DB objects.
+_GETLOGGER = re.compile(r"getLogger\([^)]*\)")
+# `CREATE [OR REPLACE] TABLE|VIEW|FUNCTION|... [IF NOT EXISTS] lakets.<object>`.
+_DEFINITION = re.compile(
+    r"CREATE\s+(?:OR\s+REPLACE\s+)?"
+    r"(?:TABLE|VIEW|MATERIALIZED\s+VIEW|FUNCTION|AGGREGATE|PROCEDURE)\s+"
+    r"(?:IF\s+NOT\s+EXISTS\s+)?lakets\.([a-zA-Z_][a-zA-Z0-9_]*)",
+    re.IGNORECASE,
+)
+
+
+def _defined_lakets_objects() -> set:
+    """All lakets.* tables/views/functions/aggregates defined across sql/*.sql."""
+    defined = set()
+    for path in glob.glob(SQL_GLOB):
+        with open(path) as f:
+            defined.update(_DEFINITION.findall(f.read()))
+    return defined
+
+
+def _referenced_lakets_objects(source: str) -> set:
+    """lakets.* objects referenced in a workflow file, excluding logger names."""
+    return set(_LAKETS_REF.findall(_GETLOGGER.sub("", source)))
+
+
+class TestSchemaReferences:
+    """Every ``lakets.<object>`` the workflow jobs reference must exist in the
+    SQL modules. Guards against schema drift like the hypertable->chronotable
+    rename that left ``lakets._hypertable_registry`` references behind in
+    partition_manager.py / retention_job.py and only failed at runtime."""
+
+    def test_sql_definitions_parse(self):
+        """Sanity: the SQL modules yield a non-empty set of lakets objects."""
+        defined = _defined_lakets_objects()
+        assert "_chronotable_registry" in defined, \
+            "expected core registries in sql/*.sql — check SQL_GLOB / regex"
+
+    def test_workflow_lakets_references_are_defined(self):
+        """No workflow file may reference a lakets object absent from sql/*.sql."""
+        defined = _defined_lakets_objects()
+        problems = []
+        for path in sorted(glob.glob(WORKFLOW_GLOB)):
+            refs = _referenced_lakets_objects(_read_source(path))
+            missing = sorted(r for r in refs if r not in defined)
+            if missing:
+                problems.append(f"{path.split('/')[-1]}: {missing}")
+        assert not problems, (
+            "Workflow jobs reference lakets objects not defined in sql/*.sql "
+            "(schema drift):\n  " + "\n  ".join(problems)
+        )