diff --git a/notmuch-tag.c b/notmuch-tag.c
index 36b9b092..0a6b140c 100644
--- a/notmuch-tag.c
+++ b/notmuch-tag.c
@@ -53,10 +53,14 @@ _escape_tag (char *buf, const char *tag)
     return buf;
 }
 
+typedef struct {
+    const char *tag;
+    notmuch_bool_t remove;
+} tag_operation_t;
+
 static char *
-_optimize_tag_query (void *ctx, const char *orig_query_string, char *argv[],
-		     int *add_tags, int add_tags_count,
-		     int *remove_tags, int remove_tags_count)
+_optimize_tag_query (void *ctx, const char *orig_query_string,
+		     const tag_operation_t *tag_ops)
 {
     /* This is subtler than it looks.  Xapian ignores the '-' operator
      * at the beginning both queries and parenthesized groups and,
@@ -71,15 +75,16 @@ _optimize_tag_query (void *ctx, const char *orig_query_string, char *argv[],
     int i;
     unsigned int max_tag_len = 0;
 
+    /* Don't optimize if there are no tag changes. */
+    if (tag_ops[0].tag == NULL)
+	return talloc_strdup (ctx, orig_query_string);
+
     /* Allocate a buffer for escaping tags.  This is large enough to
      * hold a fully escaped tag with every character doubled plus
      * enclosing quotes and a NUL. */
-    for (i = 0; i < add_tags_count; i++)
-	if (strlen (argv[add_tags[i]] + 1) > max_tag_len)
-	    max_tag_len = strlen (argv[add_tags[i]] + 1);
-    for (i = 0; i < remove_tags_count; i++)
-	if (strlen (argv[remove_tags[i]] + 1) > max_tag_len)
-	    max_tag_len = strlen (argv[remove_tags[i]] + 1);
+    for (i = 0; tag_ops[i].tag; i++)
+	if (strlen (tag_ops[i].tag) > max_tag_len)
+	    max_tag_len = strlen (tag_ops[i].tag);
     escaped = talloc_array(ctx, char, max_tag_len * 2 + 3);
     if (!escaped)
 	return NULL;
@@ -90,16 +95,11 @@ _optimize_tag_query (void *ctx, const char *orig_query_string, char *argv[],
     else
 	query_string = talloc_asprintf (ctx, "( %s ) and (", orig_query_string);
 
-    for (i = 0; i < add_tags_count && query_string; i++) {
+    for (i = 0; tag_ops[i].tag && query_string; i++) {
 	query_string = talloc_asprintf_append_buffer (
-	    query_string, "%snot tag:%s", join,
-	    _escape_tag (escaped, argv[add_tags[i]] + 1));
-	join = " or ";
-    }
-    for (i = 0; i < remove_tags_count && query_string; i++) {
-	query_string = talloc_asprintf_append_buffer (
-	    query_string, "%stag:%s", join,
-	    _escape_tag (escaped, argv[remove_tags[i]] + 1));
+	    query_string, "%s%stag:%s", join,
+	    tag_ops[i].remove ? "" : "not ",
+	    _escape_tag (escaped, tag_ops[i].tag));
 	join = " or ";
     }
 
@@ -113,9 +113,8 @@ _optimize_tag_query (void *ctx, const char *orig_query_string, char *argv[],
 int
 notmuch_tag_command (void *ctx, int argc, char *argv[])
 {
-    int *add_tags, *remove_tags;
-    int add_tags_count = 0;
-    int remove_tags_count = 0;
+    tag_operation_t *tag_ops;
+    int tag_ops_count = 0;
     char *query_string;
     notmuch_config_t *config;
     notmuch_database_t *notmuch;
@@ -133,35 +132,33 @@ notmuch_tag_command (void *ctx, int argc, char *argv[])
     action.sa_flags = SA_RESTART;
     sigaction (SIGINT, &action, NULL);
 
-    add_tags = talloc_size (ctx, argc * sizeof (int));
-    if (add_tags == NULL) {
-	fprintf (stderr, "Out of memory.\n");
-	return 1;
-    }
-
-    remove_tags = talloc_size (ctx, argc * sizeof (int));
-    if (remove_tags == NULL) {
-	fprintf (stderr, "Out of memory.\n");
-	return 1;
-    }
-
     argc--; argv++; /* skip subcommand argument */
 
+    /* Array of tagging operations (add or remove), terminated with an
+     * empty element. */
+    tag_ops = talloc_array (ctx, tag_operation_t, argc + 1);
+    if (tag_ops == NULL) {
+	fprintf (stderr, "Out of memory.\n");
+	return 1;
+    }
+
     for (i = 0; i < argc; i++) {
 	if (strcmp (argv[i], "--") == 0) {
 	    i++;
 	    break;
 	}
-	if (argv[i][0] == '+') {
-	    add_tags[add_tags_count++] = i;
-	} else if (argv[i][0] == '-') {
-	    remove_tags[remove_tags_count++] = i;
+	if (argv[i][0] == '+' || argv[i][0] == '-') {
+	    tag_ops[tag_ops_count].tag = argv[i] + 1;
+	    tag_ops[tag_ops_count].remove = (argv[i][0] == '-');
+	    tag_ops_count++;
 	} else {
 	    break;
 	}
     }
 
-    if (add_tags_count == 0 && remove_tags_count == 0) {
+    tag_ops[tag_ops_count].tag = NULL;
+
+    if (tag_ops_count == 0) {
 	fprintf (stderr, "Error: 'notmuch tag' requires at least one tag to add or remove.\n");
 	return 1;
     }
@@ -175,9 +172,7 @@ notmuch_tag_command (void *ctx, int argc, char *argv[])
 
     /* Optimize the query so it excludes messages that already have
      * the specified set of tags. */
-    query_string = _optimize_tag_query (ctx, query_string, argv,
-					add_tags, add_tags_count,
-					remove_tags, remove_tags_count);
+    query_string = _optimize_tag_query (ctx, query_string, tag_ops);
     if (query_string == NULL) {
 	fprintf (stderr, "Out of memory.\n");
 	return 1;
@@ -211,12 +206,12 @@ notmuch_tag_command (void *ctx, int argc, char *argv[])
 
 	notmuch_message_freeze (message);
 
-	for (i = 0; i < remove_tags_count; i++)
-	    notmuch_message_remove_tag (message,
-					argv[remove_tags[i]] + 1);
-
-	for (i = 0; i < add_tags_count; i++)
-	    notmuch_message_add_tag (message, argv[add_tags[i]] + 1);
+	for (i = 0; tag_ops[i].tag; i++) {
+	    if (tag_ops[i].remove)
+		notmuch_message_remove_tag (message, tag_ops[i].tag);
+	    else
+		notmuch_message_add_tag (message, tag_ops[i].tag);
+	}
 
 	notmuch_message_thaw (message);
 
diff --git a/test/tagging b/test/tagging
index 3acf1bc0..e4782ed4 100755
--- a/test/tagging
+++ b/test/tagging
@@ -43,7 +43,7 @@ notmuch tag +tag4 -tag4 One
 notmuch tag -tag4 +tag4 Two
 output=$(notmuch search \* | notmuch_search_sanitize)
 test_expect_equal "$output" "\
-thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; One (:\"  inbox tag1 tag4 unread)
+thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; One (:\"  inbox tag1 unread)
 thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; Two (inbox tag1 tag4 unread)"
 
 test_done