diff --git a/scripts/test-multiplayer-sql.mjs b/scripts/test-multiplayer-sql.mjs
index 6656394..b701260 100644
--- a/scripts/test-multiplayer-sql.mjs
+++ b/scripts/test-multiplayer-sql.mjs
@@ -102,7 +102,7 @@ try {
       "Guest",
     ]);
     const roster = (await act(moderationRoom, 1)).players;
-    const friend = roster.find((p) => p.name === "Account friend");
+    let friend = roster.find((p) => p.name === "Account friend");
     let guest = roster.find((p) => p.name === "Guest");
     const community = async (who, action, payload = {}) =>
       (
@@ -180,11 +180,33 @@ try {
       secret(3),
       "Guest",
     ]);
+    await community(1, "unadmin", { playerId: friend.id });
+    await chat(2, "Signed-in player", randomUUID());
+    await act(moderationRoom, 2, "leave");
+    await db.query("select public.join_multiplayer_room($1,$2,$3,$4)", [
+      moderationRoom,
+      secret(8),
+      secondAccount,
+      "Ignored",
+    ]);
+    await assert.rejects(
+      chat(8, "Different browser", randomUUID()),
+      /slow mode/,
+    );
+    await db.query(
+      "update public.party_chat_account_cooldowns set last_message_at=clock_timestamp()-interval '11 seconds' where room_id=$1 and account_id=$2",
+      [moderationRoom, secondAccount],
+    );
+    await chat(8, "Allowed after the delay", randomUUID());
+    friend = (await act(moderationRoom, 1)).players.find(
+      (p) => p.name === "Account friend",
+    );
+    assert.ok(friend);
     await community(1, "ban", { playerId: friend.id });
     await assert.rejects(
       db.query("select public.join_multiplayer_room($1,$2,$3,$4)", [
         moderationRoom,
-        secret(8),
+        secret(9),
         secondAccount,
         "Ignored",
       ]),
@@ -194,10 +216,14 @@ try {
     const privileges = (
       await db.query(`select
       has_table_privilege('anon','public.party_chat_cooldowns','select') as anon_read,
-      has_table_privilege('authenticated','public.party_chat_cooldowns','select') as authenticated_read`)
+      has_table_privilege('authenticated','public.party_chat_cooldowns','select') as authenticated_read,
+      has_table_privilege('anon','public.party_chat_account_cooldowns','select') as anon_account_read,
+      has_table_privilege('authenticated','public.party_chat_account_cooldowns','select') as authenticated_account_read`)
     ).rows[0];
     assert.equal(privileges.anon_read, false);
     assert.equal(privileges.authenticated_read, false);
+    assert.equal(privileges.anon_account_read, false);
+    assert.equal(privileges.authenticated_account_read, false);
     await db.query("delete from public.multiplayer_rooms where id=$1", [
       moderationRoom,
     ]);
diff --git a/supabase/migrations/20261027120223_party_chat_account_cooldowns.sql b/supabase/migrations/20261027120223_party_chat_account_cooldowns.sql
new file mode 100644
index 0000000..36f958a
--- /dev/null
+++ b/supabase/migrations/20261027120223_party_chat_account_cooldowns.sql
@@ -0,0 +1,58 @@
+-- Serialize the backfill with room joins, leaves, and chat writes.
+lock table public.multiplayer_rooms in exclusive mode;
+
+create table public.party_chat_account_cooldowns (
+  room_id uuid not null references public.multiplayer_rooms(id) on delete cascade,
+  account_id uuid not null references public.profiles(id) on delete cascade,
+  last_message_at timestamptz not null,
+  primary key(room_id, account_id)
+);
+create index party_chat_account_cooldowns_account on public.party_chat_account_cooldowns(account_id);
+alter table public.party_chat_account_cooldowns enable row level security;
+revoke all on public.party_chat_account_cooldowns from public, anon, authenticated;
+grant all on public.party_chat_account_cooldowns to service_role;
+
+-- Include the retained browser cooldown even when a player's messages were deleted.
+insert into public.party_chat_account_cooldowns(room_id, account_id, last_message_at)
+select p.room_id, p.account_id, max(c.last_message_at)
+from public.multiplayer_players p
+join public.party_chat_cooldowns c on c.room_id=p.room_id and c.access_hash=p.access_hash
+where p.account_id is not null
+group by p.room_id, p.account_id;
+
+create or replace function public.multiplayer_chat(p_room uuid,p_access_hash text,p_text text default null,p_client_id uuid default null)
+returns jsonb language plpgsql security invoker set search_path='' as $$
+declare room public.multiplayer_rooms; player public.multiplayer_players; result jsonb; duplicate_message boolean;
+begin
+ select * into room from public.multiplayer_rooms where id=p_room for update;
+ select * into player from public.multiplayer_players where room_id=p_room and access_hash=p_access_hash and not has_left;
+ duplicate_message := player.id is not null and p_client_id is not null and exists(
+  select 1 from public.multiplayer_messages where room_id=p_room and player_id=player.id and client_id=p_client_id
+ );
+ if player.id is not null and p_text is not null and room.chat_slow_seconds>0 and player.id<>room.host_player_id
+  and not exists(select 1 from public.party_moderators where room_id=p_room and player_id=player.id)
+  and not duplicate_message
+  and (exists(select 1 from public.party_chat_cooldowns where room_id=p_room and access_hash=p_access_hash
+    and last_message_at>clock_timestamp()-make_interval(secs=>room.chat_slow_seconds))
+   or (player.account_id is not null and exists(select 1 from public.party_chat_account_cooldowns
+    where room_id=p_room and account_id=player.account_id
+    and last_message_at>clock_timestamp()-make_interval(secs=>room.chat_slow_seconds))))
+ then raise exception 'Chat slow mode: wait before sending another message'; end if;
+ result:=public.multiplayer_chat_unchecked(p_room,p_access_hash,p_text,p_client_id);
+ if player.id is not null and p_text is not null and p_client_id is not null and not duplicate_message then
+  insert into public.party_chat_cooldowns(room_id,access_hash,last_message_at)
+  values(p_room,p_access_hash,clock_timestamp())
+  on conflict(room_id,access_hash) do update set last_message_at=excluded.last_message_at;
+  if player.account_id is not null then
+   insert into public.party_chat_account_cooldowns(room_id,account_id,last_message_at)
+   values(p_room,player.account_id,clock_timestamp())
+   on conflict(room_id,account_id) do update set last_message_at=excluded.last_message_at;
+  end if;
+ end if;
+ return jsonb_set(result,'{messages}',coalesce((select jsonb_agg(msg || jsonb_build_object('tag',tag.tag) order by ord)
+  from jsonb_array_elements(result->'messages') with ordinality x(msg,ord)
+  left join public.party_tags tag on tag.room_id=p_room and tag.player_id=(msg->>'playerId')::uuid),'[]'::jsonb));
+end; $$;
+revoke all on function public.multiplayer_chat(uuid,text,text,uuid) from public,anon,authenticated;
+grant execute on function public.multiplayer_chat(uuid,text,text,uuid) to service_role;
+notify pgrst,'reload schema';