diff --git a/docs/dev/dev.rst b/docs/dev/dev.rst
index 14f7662b..ff5e6d1c 100644
--- a/docs/dev/dev.rst
+++ b/docs/dev/dev.rst
@@ -3,6 +3,6 @@ Developer Guide
 
  .. toctree::
 
-    extending
     contributing
-    tools
\ No newline at end of file
+    under_the_hood
+    extending
\ No newline at end of file
diff --git a/docs/dev/tools.rst b/docs/dev/tools.rst
deleted file mode 100644
index 257fc0e2..00000000
--- a/docs/dev/tools.rst
+++ /dev/null
@@ -1,13 +0,0 @@
-Developer Tools
-===============
-
-Custom Model Builders
----------------------
-The following decorator should be used for new model builders, e.g. ::
-
-  @nequip.model.model_builder
-  def my_new_model_builder(arg1, arg2):
-      return model(arg1, arg2)
-
-
-.. autofunction:: nequip.model.model_builder
\ No newline at end of file
diff --git a/docs/dev/under_the_hood.rst b/docs/dev/under_the_hood.rst
new file mode 100644
index 00000000..0b118a6f
--- /dev/null
+++ b/docs/dev/under_the_hood.rst
@@ -0,0 +1,23 @@
+Under The Hood
+##############
+
+This page explains key aspects of the infrastructure.
+
+Model Building
+==============
+
+
+Model Builder Decorator
+-----------------------
+The following decorator should be used for new model builders, e.g. ::
+
+  @nequip.model.model_builder
+  def my_new_model_builder(arg1, arg2):
+      return model(arg1, arg2)
+
+
+.. autofunction:: nequip.model.model_builder
+
+Dtypes in Model Building
+------------------------
+``model_dtype`` is imposed by using ``torch.set_default_dtype()`` to set the default ``dtype`` to ``model_dtype`` for the duration of model building, such that parameter tensors created during model building will be in the default ``dtype``, which was set to ``model_dtype``.
\ No newline at end of file