feat(py): add directory and file prompt loading in genkit matching JS SDK

py/packages/genkit/src/genkit/ai/_registry.py

@@ -296,6 +296,7 @@ def define_indexer(
             description: Optional description for the indexer.
         """
         indexer_meta = metadata if metadata else {}
+
         if 'indexer' not in indexer_meta:
             indexer_meta['indexer'] = {}
         if 'label' not in indexer_meta['indexer'] or not indexer_meta['indexer']['label']:
@@ -323,7 +324,7 @@ def define_evaluator(
         metadata: dict[str, Any] | None = None,
         description: str | None = None,
     ) -> Action:
-        """Define a evaluator action.
+        """Define an evaluator action.
 
         This action runs the callback function on the every sample of
         the input dataset.
@@ -607,6 +608,38 @@ def define_prompt(
             use=use,
         )
 
+    async def prompt(
+        self,
+        name: str,
+        variant: str | None = None,
+    ):
+        """Look up a prompt by name and optional variant.
+
+        This matches the JavaScript prompt() function behavior.
+
+        Can look up prompts that were:
+        1. Defined programmatically using define_prompt()
+        2. Loaded from .prompt files using load_prompt_folder()
+
+        Args:
+            registry: The registry to look up the prompt from.
+            name: The name of the prompt.
+            variant: Optional variant name.
+            dir: Optional directory parameter (accepted for compatibility but not used).
+
+        Returns:
+            An ExecutablePrompt instance.
+
+        Raises:
+            GenkitError: If the prompt is not found.
+        """
+
+        return await lookup_prompt(
+            registry=self.registry,
+            name=name,
+            variant=variant,
+        )
+
 
 class FlowWrapper:
     """A wapper for flow functions to add `stream` method."""