diff --git a/src/commands/set-parameters.yml b/src/commands/set-parameters.yml
index 47631d1..1f9783c 100755
--- a/src/commands/set-parameters.yml
+++ b/src/commands/set-parameters.yml
@@ -14,7 +14,8 @@ parameters:
     default: ""
     description: >
       Mapping of path regular expressions to pipeline parameters and
-      values. One mapping per line, whitespace-delimited.
+      values. One mapping per line, whitespace-delimited. If duplicate
+      parameter keys are found, the last matching pattern will apply.
   output-path:
     type: string
     default: "/tmp/pipeline-parameters.json"