diff --git a/src/bespokelabs/curator/llm/llm.py b/src/bespokelabs/curator/llm/llm.py
index a43c14e0..833e16cc 100644
--- a/src/bespokelabs/curator/llm/llm.py
+++ b/src/bespokelabs/curator/llm/llm.py
@@ -78,6 +78,7 @@ def __init__(
         generation_params: dict | None = None,
         backend_params: BackendParamsType | None = None,
         system_prompt: str | None = None,
+        default_app_id: Optional[str] = None,
     ):
         """Initialize a LLM.
 
@@ -117,6 +118,7 @@ def __init__(
                     - gpu_memory_utilization: The GPU memory utilization to use for the VLLM backend
                     - batch_size: The size of the batch to use, only used if batch is True
             system_prompt: The system prompt to use for the LLM
+            default_app_id: The default application ID to use when opening datasets in Curator Viewer
         """
         generation_params = generation_params or {}
 
@@ -143,6 +145,8 @@ def __init__(
             return_completions_object=self.return_completions_object,
         )
 
+        self.default_app_id = default_app_id
+
     def _hash_fingerprint(self, dataset_hash: str = "", disable_cache: bool = False):
         if disable_cache:
             fingerprint = xxh64(os.urandom(8)).hexdigest()
@@ -262,6 +266,10 @@ def __call__(
             "run_hash": fingerprint,
             "batch_mode": self.batch_mode,
         }
+        
+        # Only include default_app_id in metadata dictionary if it's not None
+        if self.default_app_id is not None:
+            metadata_dict["default_app_id"] = self.default_app_id
 
         existing_session_id = metadata_db.get_existing_session_id(metadata_dict["run_hash"])
         existing_viewer_sync = metadata_db.check_existing_hosted_sync(metadata_dict["run_hash"])