diff --git a/eval_protocol/mcp_servers/tau2/tests/test_tau2_e2e.py b/eval_protocol/mcp_servers/tau2/tests/test_tau2_e2e.py
index 5003ae16..03a61be4 100644
--- a/eval_protocol/mcp_servers/tau2/tests/test_tau2_e2e.py
+++ b/eval_protocol/mcp_servers/tau2/tests/test_tau2_e2e.py
@@ -747,15 +747,28 @@ def tau2_airline_eval(
         elif role == "user":
             trajectory_objects.append(UserMessage(role=role, content=content))
         elif role == "tool":
-            tool_id = msg.tool_call_id
+            tool_id = msg.tool_call_id or ""
             trajectory_objects.append(ToolMessage(id=tool_id, role=role, content=content, requestor="assistant"))
 
     reward = 1.0
 
+    # Convert incoming action dicts to typed Action objects for the evaluator
+    action_objs: Optional[List[Action]] = None
+    if actions is not None:
+        action_objs = []
+        for a in actions:
+            if isinstance(a, Action):
+                action_objs.append(a)
+            elif isinstance(a, dict):
+                action_objs.append(Action(**a))
+            else:
+                raise TypeError("actions must be a list of Action or dict items")
+
     evaluation_criteria = EvaluationCriteria(
         nl_assertions=nl_assertions,
         communicate_info=communicate_info,
-        actions=actions,
+        actions=action_objs,
+        env_assertions=None,
         reward_basis=[
             RewardType.NL_ASSERTION,
             RewardType.DB,
@@ -796,7 +809,8 @@ def tau2_airline_eval(
     action_bases = {RewardType.ACTION}
     nl_bases = {RewardType.NL_ASSERTION}
     comm_bases = {RewardType.COMMUNICATE}
-    task_reward_basis = set(task.evaluation_criteria.reward_basis)
+    # task.evaluation_criteria can be Optional in the type hints; guard for None
+    task_reward_basis = set(task.evaluation_criteria.reward_basis) if task.evaluation_criteria else set()
 
     reward_breakdown = {}
     if task_reward_basis & env_bases:
diff --git a/eval_protocol/rewards/lean_prover.py b/eval_protocol/rewards/lean_prover.py
index 347cf6a4..45b23bf5 100644
--- a/eval_protocol/rewards/lean_prover.py
+++ b/eval_protocol/rewards/lean_prover.py
@@ -467,17 +467,16 @@ def deepseek_huggingface_prover_benchmark(
         current_top_level_reason += f" Sub-evaluation: {result_reason}"
 
     if verbose:
+        info_payload = {
+            "id": (dataset_item.get("id", "") if dataset_item else ""),
+            "has_expected_proof": expected_proof is not None,
+            "has_reference_solution": reference_solution is not None,
+            "has_answer": (("answer" in dataset_item) if dataset_item else False),
+        }
         combined_metrics["dataset_info"] = MetricResult(
             score=1.0,
             is_score_valid=True,
-            reason=json.dumps(
-                {
-                    "id": dataset_item.get("id", ""),
-                    "has_expected_proof": expected_proof is not None,
-                    "has_reference_solution": reference_solution is not None,
-                    "has_answer": "answer" in dataset_item if dataset_item else False,
-                }
-            ),
+            reason=json.dumps(info_payload),
         )
 
     return EvaluateResult(score=result_score, reason=current_top_level_reason, metrics=combined_metrics)
diff --git a/eval_protocol/typed_interface.py b/eval_protocol/typed_interface.py
index 97dafdf3..19146a1c 100644
--- a/eval_protocol/typed_interface.py
+++ b/eval_protocol/typed_interface.py
@@ -13,6 +13,7 @@
     cast,
     get_args,
     get_origin,
+    overload,
 )
 
 from pydantic import TypeAdapter, ValidationError
@@ -36,6 +37,33 @@
 F = TypeVar("F", bound=Callable[..., Any])
 
 
+# Precise overloads help static type checkers preserve the original function signature.
+@overload
+def reward_function(
+    _func: F,
+    *,
+    mode: EvaluationMode = "pointwise",
+    id: Optional[str] = None,
+    requirements: Optional[List[str]] = None,
+    resources: Optional[ResourceDict] = None,
+    concurrency: Optional[int] = None,
+    timeout: Optional[int] = None,
+) -> F: ...
+
+
+@overload
+def reward_function(
+    _func: None = ...,  # when used as @reward_function(...)
+    *,
+    mode: EvaluationMode = "pointwise",
+    id: Optional[str] = None,
+    requirements: Optional[List[str]] = None,
+    resources: Optional[ResourceDict] = None,
+    concurrency: Optional[int] = None,
+    timeout: Optional[int] = None,
+) -> Callable[[F], F]: ...
+
+
 def reward_function(
     _func: Optional[F] = None,
     *,