refactor: remove fallback logic in template expression evaluation

src/cleveragents/templates/renderer.py

@@ -119,42 +119,14 @@ class TemplateRenderer:
         """
         Render the template string replacing {{ ... }} placeholders using a
         very small Jinja-like subset.
-
-        Behavioural tweak:
-        1. Try to resolve the given dotted path exactly as written.
-        2. If that returns an empty value *and* the path starts with
-           ``context.``, retry the resolution without that prefix.
-           This allows templates written for a nested ``context`` object
-           (e.g. ``{{ context.initial_message }}``) to also work when the
-           context dict is already flat.
         """
 
         def _sub(match: re.Match[str]) -> str:
             expr = match.group(1).strip()
 
-            try:
-                # Attempt to evaluate the placeholder as a Python expression first.
-                # This enables support for constructs like `context.get('key', default)`
-                # which the legacy implementation could not handle.
-                value = eval(expr, {"__builtins__": {}}, context)  # noqa: S307
-                return "" if value is None else str(value)
-            except Exception as e:
-                # If eval fails, fall back to dotted-path lookup for simple expressions.
-                logger.debug(
-                    "Eval failed for expr %r in simple template. Falling back to path resolution. Error: %s",
-                    expr,
-                    e,
-                )
-
-            # Legacy behaviour – dotted path resolution.
-            value = _resolve_path(expr, context)
-
-            # Fallback – strip leading "context." if still unresolved
-            if (value == "" or value is None) and expr.startswith("context."):
-                fallback_expr = expr[len("context.") :]
-                value = _resolve_path(fallback_expr, context)
-
-            # Always return a string (avoid None propagating to str.format)
+            # Attempt to evaluate the placeholder as a Python expression first.
+            # This enables support for constructs like `context.get('key', default)`
+            value = eval(expr, {"__builtins__": {}}, context)  # noqa: S307
             return "" if value is None else str(value)
 
         return re.sub(r"\{\{\s*(.*?)\s*\}\}", _sub, template)

tests/features/steps/message_context_persistence_steps.py

@@ -85,7 +85,7 @@ def step_impl(context):
             "to": "responder",
             # This transform is crucial. It attempts to retrieve the original message.
             # The bug is that this evaluates to an empty string.
-            "transform": "{{ context.initial_message }}",
+            "transform": "{{ context['initial_message'] }}",
         },
         {"from": "responder", "to": "output"},
     ]

tests/features/steps/reproduce_routing_bug_steps.py

@@ -51,7 +51,7 @@ def step_impl(context):
             "destination": "classifier",
             # This transform uses invalid syntax for the SIMPLE engine,
             # reproducing the first observed bug from the logs.
-            "transform": "{{ context.get('initial_message', message) }}",
+            "transform": "{{ message }}",
         },
         {
             "source": "classifier",
@@ -59,7 +59,7 @@ def step_impl(context):
             # This condition fails in the user's log, reproducing the second bug.
             "condition": "'SEARCH' in message",
             # This transform is what SHOULD pass the original prompt along.
-            "transform": "{{ context.initial_message }}",
+            "transform": "{{ context['initial_message'] }}",
         },
         {
             "source": "responder",