diff --git a/README.md b/README.md
index d35ee9c..35a2f1e 100644
--- a/README.md
+++ b/README.md
@@ -105,4 +105,4 @@ The node name may be the class type (`TXTBatchLoader`), the display name, the wo
 - PyTorch 2.0 or newer
 - Codecs required by the selected video format
 
-Current package version: `1.2.0`
+Current package version: `1.2.1`
diff --git a/__init__.py b/__init__.py
index 58c9c82..4297a81 100644
--- a/__init__.py
+++ b/__init__.py
@@ -10,9 +10,6 @@ from .nodes.lora_batch_process import LoraBatchLoader
 from .nodes.video_batch_process import VideoBatchSaver  # type: ignore
 from .nodes.any_batch_process import AnyBatchGroup, AssetFilter
 from .nodes.model3d_batch_process import Model3DBatchSaver, Model3DBatchPreview
-from .nodes.runtime_filename_format import install_runtime_filename_substitution
-
-install_runtime_filename_substitution()
 
 WEB_DIRECTORY = "./web"
 
diff --git a/nodes/runtime_filename_format.py b/nodes/runtime_filename_format.py
index 2ed3604..cb0643a 100644
--- a/nodes/runtime_filename_format.py
+++ b/nodes/runtime_filename_format.py
@@ -70,6 +70,7 @@ def record_runtime_output(
     prompt_id=None,
 ):
     """Record a node output so a saver can reference it in the same prompt."""
+    install_runtime_filename_substitution()
     aliases = {str(node_type)}
     if display_name:
         aliases.add(str(display_name))
@@ -99,6 +100,7 @@ def replace_runtime_placeholders(text, prompt_id=None):
     if not isinstance(text, str) or "%" not in text:
         return text
 
+    install_runtime_filename_substitution()
     resolved_prompt_id = prompt_id if prompt_id is not None else _current_prompt_id()
     with _LOCK:
         values = {}
@@ -120,7 +122,11 @@ def replace_runtime_placeholders(text, prompt_id=None):
 
 
 def install_runtime_filename_substitution():
-    """Install the lightweight hook used by all ComfyUI saver nodes."""
+    """Install the lightweight hook used by all ComfyUI saver nodes.
+
+    Called lazily from record/replace instead of at import time, so loading
+    this package never modifies the host application by itself.
+    """
     try:
         import folder_paths
     except ImportError:
diff --git a/pyproject.toml b/pyproject.toml
index 74905ae..577dc2a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [project]
 name = "batch-process"
 description = "A collection of nodes for batch processing texts, images, videos, and LoRAs in ComfyUI"
-version = "1.2.0"
+version = "1.2.1"
 license = {file = "LICENSE"}
 
 [project.urls]