--- a/doc/Host-tools-overview	Fri Mar 19 05:19:56 2021 +0000
+++ b/doc/Host-tools-overview	Fri Mar 19 06:02:36 2021 +0000
@@ -187,6 +187,20 @@
 		for talking to serially-interfaced devices that mix ASCII with
 		binary in their serial talk.
 
+fc-simint	This program is a specialized front end to fc-simtool, allowing
+		the latter tool to operate on SIM cards inside Calypso phones
+		and development boards.  fc-simint loads and runs simagent on
+		the Calypso device in the manner of loadtools, then passes the
+		open file descriptor to fc-simtool.
+
+fc-simtool	Maintained in a separate fc-sim-tools repository, fc-simtool is
+		our tool for operating on SIM cards.  Its primary mode of usage
+		is operating on SIM cards inserted into special smart card
+		reader/programmer devices, without going through any kind of
+		phone or other GSM device, but fc-simtool can also be invoked
+		indirectly via fc-simint, in which case it operates on SIM cards
+		inside Calypso devices.
+
 fc-tch2fr	This hack-utility takes a TCH downlink recording produced with
 		the tch record command in fc-shell and converts it to a playable
 		libgsm file which will most likely contain some garbage by