diff --git a/src/builtin_actions.py b/src/builtin_actions.py
index 3d72ad9..e54eb2f 100644
--- a/src/builtin_actions.py
+++ b/src/builtin_actions.py
@@ -478,7 +478,7 @@ def _result_has_work(result: str | None) -> bool:
     'No new emails to summarize', 'Tagged 0 / Moved 0', etc. when nothing
     was done. Used to decide whether to record the run or noop it.
     """
-    if not result:
+    if not isinstance(result, str) or not result:
         return False
     low = result.lower()
     if "processed 0" in low or "no new" in low or "nothing to" in low:
@@ -554,7 +554,7 @@ _HEURISTIC_CRITICAL = ["surgery", "court", "wedding day", "funeral", "delivery d
 
 def _classify_event_heuristic(summary: str) -> tuple:
     """Quick heuristic classification — returns (event_type, importance) or (None, None) if unclear."""
-    s = (summary or "").lower()
+    s = (summary if isinstance(summary, str) else "").lower()
     etype = None
     for t, kws in _HEURISTIC_TYPES.items():
         if any(k in s for k in kws):
diff --git a/tests/test_builtin_actions_nonstring.py b/tests/test_builtin_actions_nonstring.py
new file mode 100644
index 0000000..61bd34f
--- /dev/null
+++ b/tests/test_builtin_actions_nonstring.py
@@ -0,0 +1,21 @@
+"""Regression: builtin_actions heuristics must tolerate non-string input.
+
+_result_has_work did `result.lower()` after a falsy-only guard, and
+_classify_event_heuristic did `(summary or "").lower()`; a truthy non-string
+(e.g. a dict) raised AttributeError. They now coerce/guard non-strings.
+"""
+from src.builtin_actions import _result_has_work, _classify_event_heuristic
+
+
+def test_result_has_work_non_string():
+    assert _result_has_work({"x": 1}) is False
+    assert _result_has_work(123) is False
+
+
+def test_classify_event_heuristic_non_string():
+    out = _classify_event_heuristic(123)
+    assert isinstance(out, tuple)
+
+
+def test_valid_inputs_unchanged():
+    assert _result_has_work("Processed 0 emails") is False