diff --git a/workflows/tests/test_workflow_execution.py b/workflows/tests/test_workflow_execution.py
index 472c645..f8eef84 100644
--- a/workflows/tests/test_workflow_execution.py
+++ b/workflows/tests/test_workflow_execution.py
@@ -158,6 +158,23 @@ def test_semantic_strategies_format(self):
 			assert 'priority' in strategy, "Strategy missing 'priority'"
 			assert 'metadata' in strategy, "Strategy missing 'metadata'"
 
+	# Test 11: _resolve_placeholders returns original string for positional format specifiers
+	def test_resolve_placeholders_positional_format_specifier(self):
+		"""Positional placeholders like {0} must not crash; original string is returned unchanged."""
+		def _resolve_placeholders(data, context):
+			if isinstance(data, str):
+				try:
+					if '{' in data and '}' in data:
+						return data.format(**context)
+					return data
+				except (KeyError, IndexError, ValueError):
+					return data
+			return data
+
+		url = "https://example.com/item/{0}/details"
+		result = _resolve_placeholders(url, {})
+		assert result == url, f"Expected original URL, got: {result}"
+
 		# Validate semantic-only (no CSS/xpath)
 		strategy_types = [s['type'] for s in strategies]
 		assert 'css' not in strategy_types, 'Should not have CSS strategies'
diff --git a/workflows/workflow_use/workflow/service.py b/workflows/workflow_use/workflow/service.py
index 1a6c325..b4656a2 100644
--- a/workflows/workflow_use/workflow/service.py
+++ b/workflows/workflow_use/workflow/service.py
@@ -517,9 +517,11 @@ def _resolve_placeholders(self, data: Any) -> Any:
 					formatted_data = data.format(**self.context)
 					return formatted_data
 				return data  # No placeholders, return as is
-			except KeyError:
-				# A key in the placeholder was not found in the context.
-				# Return the original string as per previous behavior.
+			except (KeyError, IndexError, ValueError):
+				# A key in the placeholder was not found in the context (KeyError),
+				# or a positional format specifier like {0} was present (IndexError),
+				# or the format string was otherwise invalid (ValueError).
+				# Return the original string unchanged.
 				return data
 
 		# TODO: This next things are not really supported atm, we'll need to to do it in the future.