diff --git a/docs/how-to/write-plans.md b/docs/how-to/write-plans.md
index cba1ab4958..a25d3e128e 100644
--- a/docs/how-to/write-plans.md
+++ b/docs/how-to/write-plans.md
@@ -42,6 +42,9 @@ Then in your plan module:
 :language: python
 ```
 
+> [!NOTE]
+> In order for this to work, the `MyDeviceComposite` needs to be made available to blueapi by importing it into the `planFunctions` module where it's needed. Factories for the individual devices within the composite also need to be available in the relevant beamline device module.
+
 
 ## Injecting Metadata