diff --git a/src/aws_durable_execution_sdk_python/execution.py b/src/aws_durable_execution_sdk_python/execution.py
index e3e7be5..5b31d53 100644
--- a/src/aws_durable_execution_sdk_python/execution.py
+++ b/src/aws_durable_execution_sdk_python/execution.py
@@ -217,8 +217,17 @@ def wrapper(event: Any, context: LambdaContext) -> MutableMapping[str, Any]:
             invocation_input = event
             service_client = invocation_input.service_client
         else:
-            logger.debug("durableExecutionArn: %s", event.get("DurableExecutionArn"))
-            invocation_input = DurableExecutionInvocationInput.from_dict(event)
+            try:
+                logger.debug(
+                    "durableExecutionArn: %s", event.get("DurableExecutionArn")
+                )
+                invocation_input = DurableExecutionInvocationInput.from_dict(event)
+            except (KeyError, TypeError, AttributeError) as e:
+                msg = (
+                    "The payload is not the correct Durable Function input. "
+                    "Please set DurableConfig on the AWS Lambda to invoke it as a Durable Function."
+                )
+                raise ExecutionError(msg) from e
 
             # Local runner always uses its own client, otherwise use custom or default
             if invocation_input.is_local_runner:
diff --git a/tests/execution_test.py b/tests/execution_test.py
index 68a06d1..57c83c7 100644
--- a/tests/execution_test.py
+++ b/tests/execution_test.py
@@ -2012,3 +2012,59 @@ def test_handler(event: Any, context: DurableContext) -> dict:
     # THEN the execution succeeds using the custom client
     assert result["Status"] == InvocationStatus.SUCCEEDED.value
     assert result["Result"] == '{"result": "success"}'
+
+
+def test_durable_execution_with_non_durable_payload_raises_error():
+    """Test that invoking a durable function with a regular event raises a helpful error."""
+
+    # GIVEN a durable function
+    @durable_execution
+    def test_handler(event: Any, context: DurableContext) -> dict:
+        return {"result": "success"}
+
+    # GIVEN a regular Lambda event (not a durable execution payload)
+    regular_event = {"key": "value", "data": "test"}
+
+    lambda_context = Mock()
+    lambda_context.aws_request_id = "test-request"
+    lambda_context.client_context = None
+    lambda_context.identity = None
+    lambda_context._epoch_deadline_time_in_ms = 1000000  # noqa: SLF001
+    lambda_context.invoked_function_arn = None
+    lambda_context.tenant_id = None
+
+    # WHEN the handler is invoked with a non-durable payload
+    # THEN it raises a ValueError with a helpful message
+    with pytest.raises(
+        ExecutionError,
+        match="The payload is not the correct Durable Function input",
+    ):
+        test_handler(regular_event, lambda_context)
+
+
+def test_durable_execution_with_non_dict_event_raises_error():
+    """Test that invoking a durable function with a non-dict event raises a helpful error."""
+
+    # GIVEN a durable function
+    @durable_execution
+    def test_handler(event: Any, context: DurableContext) -> dict:
+        return {"result": "success"}
+
+    # GIVEN a non-dict event
+    non_dict_event = "not a dict"
+
+    lambda_context = Mock()
+    lambda_context.aws_request_id = "test-request"
+    lambda_context.client_context = None
+    lambda_context.identity = None
+    lambda_context._epoch_deadline_time_in_ms = 1000000  # noqa: SLF001
+    lambda_context.invoked_function_arn = None
+    lambda_context.tenant_id = None
+
+    # WHEN the handler is invoked with a non-dict event
+    # THEN it raises a ValueError with a helpful message
+    with pytest.raises(
+        ExecutionError,
+        match="The payload is not the correct Durable Function input",
+    ):
+        test_handler(non_dict_event, lambda_context)