diff --git a/doc/coc.txt b/doc/coc.txt
index edebbb44033..568fb54e3d1 100644
--- a/doc/coc.txt
+++ b/doc/coc.txt
@@ -2445,10 +2445,12 @@ Acceptable {action} names for |CocAction()| and |CocActionAsync()|.
 
 	Get all diagnostic items of the current Neovim session.
 
-"diagnosticInfo"					*CocAction('diagnosticInfo')*
+"diagnosticInfo" [{target}]				*CocAction('diagnosticInfo')*
 
 	Show diagnostic message at the current position, do not truncate.
 
+	Optional {target} could be `float` or `echo`.
+
 "diagnosticToggle" [{enable}]	 			*CocAction('diagnosticToggle')*
 
 	Enable/disable diagnostics on the fly, not work when `displayByAle` is