diff --git a/burr/core/action.py b/burr/core/action.py
index a69db06c6..62a4021f6 100644
--- a/burr/core/action.py
+++ b/burr/core/action.py
@@ -517,8 +517,9 @@ def visit_Set(self, node: ast.Set) -> None:
 
     def visit_Dict(self, node: ast.Dict) -> None:
         for k in node.keys:
-            if k is not None:
-                self.visit(k)
+            if k is None:
+                self._reject(node, "dictionary unpacking")
+            self.visit(k)
         for v in node.values:
             self.visit(v)
 
@@ -810,7 +811,7 @@ def safe_expr(expr: str) -> "Condition":
         - ``BoolOp``: ``and``, ``or``.
         - ``UnaryOp``: ``not``, unary ``-``, unary ``+``.
         - ``BinOp`` arithmetic: ``+``, ``-``, ``*``, ``/``, ``//``, ``%``, ``**``.
-        - Literal containers: tuple, list, set, dict.
+        - Literal containers: tuple, list, set, dict. Unpacking is not supported.
         - ``Call`` only to a tight allowlist of safe builtins by name:
           ``len``, ``abs``, ``min``, ``max``, ``sum``, ``all``, ``any``, ``str``,
           ``int``, ``float``, ``bool``. All other calls are rejected.
diff --git a/tests/core/test_action.py b/tests/core/test_action.py
index 0095bdafe..213ba9ee2 100644
--- a/tests/core/test_action.py
+++ b/tests/core/test_action.py
@@ -418,6 +418,26 @@ def test_safe_expr_literal_containers():
     assert _eval_value(Condition.safe_expr("{'a': 1, 'b': 2}"), {}) == {"a": 1, "b": 2}
 
 
+def test_safe_expr_dict_with_none_key():
+    cond = Condition.safe_expr("{None: 'fallback', 'allowed': True}[None] == 'fallback'")
+    assert cond.run(State({})) == {Condition.KEY: True}
+
+
+@pytest.mark.parametrize(
+    "expr_str",
+    [
+        "{**mapping}",
+        "{'allowed': True, **mapping}",
+        "{**first, **second}",
+        "[{**mapping}]",
+        "False and {**mapping}",
+    ],
+)
+def test_safe_expr_rejects_dict_unpacking_at_call_time(expr_str):
+    with pytest.raises(ValueError, match="dictionary unpacking"):
+        Condition.safe_expr(expr_str)
+
+
 def test_safe_expr_all_allowed_builtins():
     pairs = [
         ("len(items)", {"items": [1, 2, 3]}, 3),