diff --git a/batch/makedist.sh b/batch/makedist.sh
index 3b55852fc..bd753ee68 100755
--- a/batch/makedist.sh
+++ b/batch/makedist.sh
@@ -220,6 +220,7 @@ src/assigners/a_preference.php
 src/assigners/a_review.php
 src/assigners/a_status.php
 src/assigners/a_tag.php
+src/assigners/a_taganno.php
 src/assigners/a_unsubmitreview.php
 src/assignmentcountset.php
 src/assignmentset.php
diff --git a/src/assigners/a_copytag.php b/src/assigners/a_copytag.php
index 51faa4569..f4be91872 100644
--- a/src/assigners/a_copytag.php
+++ b/src/assigners/a_copytag.php
@@ -10,10 +10,15 @@ function __construct(Conf $conf, $aj) {
         $this->move = $aj->move ?? false;
     }
     function load_state(AssignmentState $state) {
-        Tag_AssignmentParser::load_tag_state($state);
+        Tag_Assignable::load($state);
+        TagAnno_Assignable::load($state);
+    }
+    function paper_universe($req, AssignmentState $state) {
+        return "reqpost";
     }
     function allow_paper(PaperInfo $prow, AssignmentState $state) {
-        if (($whyNot = $state->user->perm_edit_some_tag($prow))) {
+        if ($prow->paperId > 0
+            && ($whyNot = $state->user->perm_edit_some_tag($prow))) {
             return new AssignmentError($whyNot);
         } else {
             return true;
@@ -35,6 +40,7 @@ function apply(PaperInfo $prow, Contact $contact, $req, AssignmentState $state)
             $state->error($tagger->error_ftext(true));
             return false;
         }
+        $ltag = strtolower($tag);
         $new_tag = $tagger->check($req["new_tag"] ?? "", Tagger::NOVALUE);
         if (!$new_tag) {
             if ($tagger->error_code() === Tagger::EEMPTY) {
@@ -46,7 +52,8 @@ function apply(PaperInfo $prow, Contact $contact, $req, AssignmentState $state)
         }
 
         // if you can't view the tag, you can't copy or move the tag
-        if (!$state->user->can_view_tag($prow, $tag)) {
+        if ($prow->paperId > 0
+            && !$state->user->can_view_tag($prow, $tag)) {
             return Tag_AssignmentParser::cannot_view_error($prow, $tag, $state);
         }
 
@@ -60,18 +67,39 @@ function apply(PaperInfo $prow, Contact $contact, $req, AssignmentState $state)
             return false;
         }
 
-        $ltag = strtolower($tag);
-        $res = $state->query(new Tag_Assignable($prow->paperId, $ltag));
-        if (!$res) {
-            return true;
+        // real paper: change/move tag
+        if ($prow->paperId > 0) {
+            $res = $state->query(new Tag_Assignable($prow->paperId, $ltag));
+            if (!$res) {
+                return true;
+            }
+            assert(count($res) === 1);
+
+            $lnew_tag = strtolower($new_tag);
+            $state->add(new Tag_Assignable($prow->paperId, $lnew_tag, $new_tag, $res[0]->_index));
+            if ($this->move) {
+                $state->remove($res[0]);
+            }
         }
-        assert(count($res) === 1);
 
-        $lnew_tag = strtolower($new_tag);
-        $state->add(new Tag_Assignable($prow->paperId, $lnew_tag, $new_tag, $res[0]->_index));
-        if ($this->move) {
-            $state->remove($res[0]);
+        // placeholder: change/move tag annotations
+        if ($prow->paperId < 0
+            && $state->user->can_edit_tag_anno($tag)
+            && $state->user->can_edit_tag_anno($new_tag)
+            && ($ares = $state->query(new TagAnno_Assignable($tag, null)))) {
+            if (!$state->query(new TagAnno_Assignable($new_tag, null))) {
+                foreach ($ares as $taa) {
+                    $state->add($taa->with_tag($new_tag));
+                }
+            }
+            if ($this->move
+                && !$state->query(new Tag_Assignable(null, $ltag))) {
+                foreach ($ares as $taa) {
+                    $x = $state->remove($taa);
+                }
+            }
         }
+
         return true;
     }
 }
diff --git a/src/assigners/a_status.php b/src/assigners/a_status.php
index 0ecaed7a8..90855660b 100644
--- a/src/assigners/a_status.php
+++ b/src/assigners/a_status.php
@@ -105,7 +105,7 @@ function apply(PaperInfo $prow, Contact $contact, $req, AssignmentState $state)
                 $res->_withdrawn = Conf::$now;
                 $res->_submitted = -$res->_submitted;
                 if ($state->conf->tags()->has(TagInfo::TFM_VOTES)) {
-                    Tag_AssignmentParser::load_tag_state($state);
+                    Tag_Assignable::load($state);
                     $state->register_preapply_function("withdraw {$prow->paperId}", new Withdraw_PreapplyFunction($prow->paperId));
                 }
             }
diff --git a/src/assigners/a_tag.php b/src/assigners/a_tag.php
index 0b4f12ec9..0d2a6e30e 100644
--- a/src/assigners/a_tag.php
+++ b/src/assigners/a_tag.php
@@ -36,6 +36,16 @@ function match($q) {
             && ($q->ltag ?? $this->ltag) === $this->ltag
             && ($q->_index ?? $this->_index) === $this->_index;
     }
+    static function load(AssignmentState $state) {
+        if (!$state->mark_type("tag", ["pid", "ltag"], "Tag_Assigner::make")) {
+            return;
+        }
+        $result = $state->conf->qe("select paperId, tag, tagIndex from PaperTag where paperId?a", $state->paper_ids());
+        while (($row = $result->fetch_row())) {
+            $state->load(new Tag_Assignable(+$row[0], strtolower($row[1]), $row[1], (float) $row[2]));
+        }
+        Dbl::free($result);
+    }
 }
 
 class NextTagAssigner implements AssignmentPreapplyFunction {
@@ -78,7 +88,7 @@ function preapply(AssignmentState $state) {
         $ltag = strtolower($this->tag);
         foreach ($this->pidindex as $pid => $index) {
             if ($index >= $this->first_index && $index < $this->next_index) {
-                $x = $state->query_unmodified(new Tag_Assignable($pid, $ltag));
+                $x = $state->query_unedited(new Tag_Assignable($pid, $ltag));
                 if (!empty($x)) {
                     $state->add(new Tag_Assignable($pid, $ltag, $this->tag, $this->next_index($this->isseq), true));
                 }
@@ -110,18 +120,8 @@ function __construct(Conf $conf, $aj) {
     function expand_papers($req, AssignmentState $state) {
         return $this->itype ? "ALL" : (string) $req["paper"];
     }
-    static function load_tag_state(AssignmentState $state) {
-        if (!$state->mark_type("tag", ["pid", "ltag"], "Tag_Assigner::make")) {
-            return;
-        }
-        $result = $state->conf->qe("select paperId, tag, tagIndex from PaperTag where paperId?a", $state->paper_ids());
-        while (($row = $result->fetch_row())) {
-            $state->load(new Tag_Assignable(+$row[0], strtolower($row[1]), $row[1], (float) $row[2]));
-        }
-        Dbl::free($result);
-    }
     function load_state(AssignmentState $state) {
-        self::load_tag_state($state);
+        Tag_Assignable::load($state);
     }
     function allow_paper(PaperInfo $prow, AssignmentState $state) {
         if (($whyNot = $state->user->perm_edit_some_tag($prow))) {
diff --git a/src/assigners/a_taganno.php b/src/assigners/a_taganno.php
new file mode 100644
index 000000000..e2a39efcd
--- /dev/null
+++ b/src/assigners/a_taganno.php
@@ -0,0 +1,91 @@
+<?php
+// a_taganno.php -- HotCRP assignment helper classes
+// Copyright (c) 2006-2023 Eddie Kohler; see LICENSE.
+
+class TagAnno_Assignable extends Assignable {
+    /** @var string */
+    public $ltag;
+    /** @var int */
+    public $annoId;
+    /** @var string */
+    public $_tag;
+    /** @var ?float */
+    public $_tagIndex;
+    /** @var ?string */
+    public $_heading;
+    /** @var ?string */
+    public $_infoJson;
+    /** @param string $tag
+     * @param int $annoId
+     * @param ?float $index
+     * @param ?string $heading
+     * @param ?string $infoJson */
+    function __construct($tag, $annoId, $index = null, $heading = null, $infoJson = null) {
+        $this->type = "taganno";
+        $this->pid = 0;
+        $this->ltag = strtolower($tag);
+        $this->annoId = $annoId;
+        $this->_tag = $tag;
+        $this->_tagIndex = $index;
+        $this->_heading = $heading;
+        $this->_infoJson = $infoJson;
+    }
+    /** @return self */
+    function fresh() {
+        return new TagAnno_Assignable($this->_tag, $this->annoId);
+    }
+    /** @param string $t
+     * @return self */
+    function with_tag($t) {
+        $x = clone $this;
+        $x->ltag = strtolower($t);
+        $x->_tag = $t;
+        return $x;
+    }
+    /** @param Assignable $q
+     * @return bool */
+    function match($q) {
+        '@phan-var-force TagAnno_Assignable $q';
+        return ($q->ltag ?? $this->ltag) === $this->ltag
+            && ($q->annoId ?? $this->annoId) === $this->annoId;
+    }
+    static function load(AssignmentState $state) {
+        if (!$state->mark_type("taganno", ["ltag", "annoId"], "TagAnno_Assigner::make")) {
+            return;
+        }
+        $result = $state->conf->qe("select tag, annoId, tagIndex, heading, infoJson from PaperTagAnno");
+        while (($row = $result->fetch_row())) {
+            $state->load(new TagAnno_Assignable($row[0], +$row[1], +$row[2], $row[3], $row[4]));
+        }
+        Dbl::free($result);
+    }
+}
+
+class TagAnno_Assigner extends Assigner {
+    function __construct(AssignmentItem $item, AssignmentState $state) {
+        parent::__construct($item, $state);
+    }
+    static function make(AssignmentItem $item, AssignmentState $state) {
+        if (!$state->user->can_edit_tag_anno($item["ltag"])) {
+            throw new AssignmentError("<0>You can’t edit this tag’s annotations");
+        }
+        return new TagAnno_Assigner($item, $state);
+    }
+    function unparse_description() {
+        return "tag annotation";
+    }
+    function add_locks(AssignmentSet $aset, &$locks) {
+        $locks["PaperTagAnno"] = "write";
+    }
+    function execute(AssignmentSet $aset) {
+        if ($this->item->deleted()) {
+            $aset->stage_qe("delete from PaperTagAnno where tag=? and annoId=?",
+                            $this->item->pre("_tag"), $this->item->pre("annoId"));
+        } else {
+            $aset->stage_qe("insert into PaperTagAnno set tag=?, annoId=?, tagIndex=?, heading=?, infoJson=? ?U on duplicate key update tagIndex=?U(tagIndex), heading=?U(heading), infoJson=?U(infoJson)",
+                            $this->item->pre("_tag"), $this->item->pre("annoId"),
+                            $this->item->post("_tagIndex"), $this->item->post("_heading"),
+                            $this->item->post("_infoJson"));
+        }
+    }
+}
diff --git a/src/assignmentset.php b/src/assignmentset.php
index 280a215d8..63a5df821 100644
--- a/src/assignmentset.php
+++ b/src/assignmentset.php
@@ -83,9 +83,16 @@ function deleted() {
         return $this->deleted;
     }
     /** @return bool */
-    function modified() {
+    function edited() {
         return !!$this->after;
     }
+    /** @return bool */
+    function changed() {
+        return $this->after
+            && ($this->deleted
+                ? $this->existed
+                : !$this->existed || !$this->after->match($this->before));
+    }
     /** @param bool $pre
      * @param string $offset */
     function get($pre, $offset) {
@@ -324,10 +331,10 @@ function query($q) {
     /** @template T
      * @param T $q
      * @return list<T> */
-    function query_unmodified($q) {
+    function query_unedited($q) {
         $res = [];
         foreach ($this->query_items($q) as $item) {
-            if (!$item->modified())
+            if (!$item->edited())
                 $res[] = $item->before;
         }
         return $res;
@@ -387,8 +394,7 @@ function diff() {
         $diff = [];
         foreach ($this->st as $pid => $st) {
             foreach ($st->items as $item) {
-                if ($item->after
-                    && (!$item->existed() || !$item->after->match($item->before)))
+                if ($item->changed())
                     $diff[$pid][] = $item;
             }
         }
@@ -737,11 +743,13 @@ function __construct($type) {
         $this->type = $type;
     }
     // Return a descriptor of the set of papers relevant for this action.
-    // Returns `""` or `"none"`.
+    // `"req"`, the default, means call `apply` for each requested paper.
+    // `"none"` means call `apply` exactly once with a placeholder paper.
+    // `"reqpost"` means each requested paper, then once with a placeholder.
     /** @param CsvRow $req
-     * @return ''|'none' */
+     * @return 'req'|'none'|'reqpost' */
     function paper_universe($req, AssignmentState $state) {
-        return "";
+        return "req";
     }
     // Optionally expand the set of interesting papers. Returns a search
     // expression, such as "ALL", or false.
@@ -1608,25 +1616,27 @@ private function apply_req(AssignmentParser $aparser = null, $req) {
         $this->astate->paper_exact_match = $pfield_straight;
 
         // check conflicts and perform assignment
-        if ($paper_universe === "none") {
-            $prow = $this->astate->placeholder_prow();
-            $any_success = $this->apply_paper($prow, $contacts, $aparser, $req) === 1;
-        } else {
-            $any_success = false;
-            foreach ($pids as $p) {
-                $prow = $this->astate->prow($p);
-                if (!$prow) {
-                    $this->error("<5>" . $this->user->no_paper_whynot($p)->unparse_html());
-                } else {
-                    $ret = $this->apply_paper($prow, $contacts, $aparser, $req);
-                    if ($ret === 1) {
-                        $any_success = true;
-                    } else if ($ret < 0) {
-                        break;
-                    }
+        $any_success = false;
+        foreach ($pids as $p) {
+            $prow = $this->astate->prow($p);
+            if (!$prow) {
+                $this->error("<5>" . $this->user->no_paper_whynot($p)->unparse_html());
+            } else {
+                $ret = $this->apply_paper($prow, $contacts, $aparser, $req);
+                if ($ret === 1) {
+                    $any_success = true;
+                } else if ($ret < 0) {
+                    break;
                 }
             }
         }
+        if ($paper_universe === "none" || $paper_universe === "reqpost") {
+            $prow = $this->astate->placeholder_prow();
+            $ret = $this->apply_paper($prow, $contacts, $aparser, $req);
+            if ($ret === 1) {
+                $any_success = true;
+            }
+        }
 
         if (!$any_success) {
             $this->astate->mark_matching_errors();
diff --git a/test/t_tags.php b/test/t_tags.php
index 709bfe7fc..be4ee04ef 100644
--- a/test/t_tags.php
+++ b/test/t_tags.php
@@ -236,4 +236,51 @@ function test_tag_anno() {
 
         $this->conf->qe("delete from PaperTagAnno where tag='t'");
     }
+
+    function test_copy_tag_anno() {
+        $v = [];
+        foreach ([0, 10, 10, 10, 30, 31, 32, 50] as $i => $n) {
+            $v[] = ["t", $i + 1, $n, "H" . ($i + 1)];
+        }
+        $this->conf->qe("insert into PaperTagAnno (tag,annoId,tagIndex,heading) values ?v", $v);
+
+        $dt = $this->conf->tags()->ensure("t");
+        $dtt = $this->conf->tags()->ensure("tt");
+
+        $dt->invalidate_order_anno();
+        xassert($dt->has_order_anno());
+        $dtt->invalidate_order_anno();
+        xassert(!$dtt->has_order_anno());
+
+        xassert_assign($this->u_chair, "action,paper,tag,new_tag\ncopytag,all,t,tt\n");
+
+        $dt->invalidate_order_anno();
+        xassert($dt->has_order_anno());
+        $dtt->invalidate_order_anno();
+        xassert($dtt->has_order_anno());
+
+        $sv = [[-1, null], [0, 1], [1, 1], [10, 4], [10, 4], [12, 4], [30, 5], [31, 6], [32, 7], [33, 7], [49, 7], [50, 8], [60, 8]];
+        foreach ($sv as $m) {
+            xassert_eqq($dt->order_anno_search($m[0])->annoId ?? null, $m[1]);
+            xassert_eqq($dtt->order_anno_search($m[0])->annoId ?? null, $m[1]);
+        }
+
+        xassert_assign($this->u_chair, "action,paper,tag,new_tag\nmovetag,all,tt,tu\n");
+
+        $dtu = $this->conf->tags()->ensure("tu");
+        $dt->invalidate_order_anno();
+        xassert($dt->has_order_anno());
+        $dtt->invalidate_order_anno();
+        xassert(!$dtt->has_order_anno());
+        $dtu->invalidate_order_anno();
+        xassert($dtu->has_order_anno());
+
+        $sv = [[-1, null], [0, 1], [1, 1], [10, 4], [10, 4], [12, 4], [30, 5], [31, 6], [32, 7], [33, 7], [49, 7], [50, 8], [60, 8]];
+        foreach ($sv as $m) {
+            xassert_eqq($dt->order_anno_search($m[0])->annoId ?? null, $m[1]);
+            xassert_eqq($dtu->order_anno_search($m[0])->annoId ?? null, $m[1]);
+        }
+
+        $this->conf->qe("delete from PaperTagAnno where tag in ('t','tt','tu')");
+    }
 }