Just found out that I’ve been piping things through wc for no reason.
Heh. Here’s a quick patch, if you want to add this to the manual page.

Signed-off-by: Sandra Snan <sandra.snan@handgranat.org>
---
 notmuch.1 |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/notmuch.1 b/notmuch.1
index e573749..4d300c0 100644
--- a/notmuch.1
+++ b/notmuch.1
@@ -126,7 +126,7 @@ syntax. See the
 section below for more details on the supported syntax.
 
 The
-.BR search " and "show
+.BR "search" ", " "show" " and " "count"
 commands are used to query the email database.
 .RS 4
 .TP 4
@@ -239,6 +239,22 @@ See the
 .B "SEARCH SYNTAX"
 section below for details of the supported syntax for <search-terms>.
 .RE
+.TP
+.BR count " <search-term>..."
+
+Count messages matching the search terms.
+
+The number of matching messages is output to stdout.
+
+A common use of
+.B notmuch count
+is to display the count of messages matching both a specific tag and
+either inbox or unread
+
+See the
+.B "SEARCH SYNTAX"
+section below for details of the supported syntax for <search-terms>.
+.RE
 .RE
 
 The
-- 
1.7.0