diff --git a/README.md b/README.md
index ec289a8..c1ccc74 100644
--- a/README.md
+++ b/README.md
@@ -8,3 +8,14 @@ Or place ```/path/to/laydient.py``` in the Post-processing scripts section in Pr
 
 ## how it works
 it searches for ```LAYER_CHANGE``` in the input gcode, counts them, then generates a gradient with that number of steps. Then it searches again and inserts toolchanges into the gcode at the appropriate layers. Finally, it outputs the code as ```input-filename_gradient.gcode``` into the source directory.
+
+### toolchanges
+This script inserts the following:
+``` G10
+T#
+G11```
+
+This retracts the filament, swaps the tool, then unretracts. The rest of the toolchange/purge is up to your firmware.
+
+## IMPORTANT
+Make sure you slice your file for a single extruder, this does not take existing toolchanges into account.