diff --git a/README.md b/README.md
index f92e3a2..a5a2ec9 100644
--- a/README.md
+++ b/README.md
@@ -194,6 +194,13 @@ jobs:
     # Set this action as failed if no test results were found
     fail-on-empty: 'true'
 
+    # Controls whether test report details are collapsed or expanded.
+    # Supported options:
+    #   auto: Collapse only if all tests pass (default behavior)
+    #   always: Always collapse the report details
+    #   never: Always expand the report details
+    collapsed: 'auto'
+
     # Relative path under $GITHUB_WORKSPACE where the repository was checked out.
     working-directory: ''