diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index d55f86ef3c2..151b016679d 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -19,7 +19,9 @@ def warning_on_one_line(msg, category, filename, lineno, file=None, line=None):
     return "%s:%s: %s:\n\n%s\n\n" % (filename, lineno, category.__name__, msg)
 
 
-warnings.formatwarning = warning_on_one_line
+# Note: We no longer globally modify warnings.formatwarning to avoid polluting
+# the user's warning system. If custom warning formatting is needed internally,
+# use warnings.warn_explicit() or format within specific warning calls.
 
 
 class PlotlyRenderer(Renderer):
diff --git a/plotly/tools.py b/plotly/tools.py
index 67f828204d7..cb3332a781e 100644
--- a/plotly/tools.py
+++ b/plotly/tools.py
@@ -60,7 +60,9 @@ def warning_on_one_line(message, category, filename, lineno, file=None, line=Non
     return "%s:%s: %s:\n\n%s\n\n" % (filename, lineno, category.__name__, message)
 
 
-warnings.formatwarning = warning_on_one_line
+# Note: We no longer globally modify warnings.formatwarning to avoid polluting
+# the user's warning system. If custom warning formatting is needed internally,
+# use warnings.warn_explicit() or format within specific warning calls.
 
 
 ### mpl-related tools ###