diff --git a/.env.example b/.env.example
index f7f5c75..846f90c 100644
--- a/.env.example
+++ b/.env.example
@@ -4,6 +4,10 @@ NODE_ENV=production
 BOT_TOKEN=
 BOT_CLIENT_ID=
 BOT_CLIENT_SECRET=
+# Optional: register slash commands only on this guild (instant sync for dev).
+# Leave empty in production so commands are global. When set, global commands
+# are cleared; when empty, leftover guild-scoped commands are cleared on startup
+# so Discord does not show every command twice.
 BOT_GUILD_ID=
 DATABASE_URL=postgresql://nexumi:nexumi@postgres:5432/nexumi
 REDIS_URL=redis://redis:6379
diff --git a/apps/bot/src/commands.ts b/apps/bot/src/commands.ts
index 4f3b501..e74e256 100644
--- a/apps/bot/src/commands.ts
+++ b/apps/bot/src/commands.ts
@@ -69,38 +69,82 @@ const commands: SlashCommand[] = [
 const map = new Map(commands.map((c) => [c.data.name, c]));
 const contextMenuMap = new Map(utilityContextMenus.map((c) => [c.data.name, c]));
 
+function buildCommandBody(): object[] {
+  const seen = new Set<string>();
+  const body: object[] = [];
+  for (const command of [...commands, ...utilityContextMenus]) {
+    const json = command.data.toJSON() as { name: string; type?: number };
+    const key = `${json.type ?? 1}:${json.name}`;
+    if (seen.has(key)) {
+      logger.warn({ name: json.name, type: json.type }, 'Skipping duplicate command definition');
+      continue;
+    }
+    seen.add(key);
+    body.push(json);
+  }
+  return body;
+}
+
+/**
+ * Guild-scoped leftovers + global commands both appear in Discord's picker.
+ * Always clear the unused scope so each command shows once.
+ */
+async function clearGuildCommandLeftovers(rest: REST, clientId: string): Promise<number> {
+  const guilds = (await rest.get(Routes.userGuilds())) as Array<{ id: string }>;
+  let cleared = 0;
+  for (const guild of guilds) {
+    const existing = (await rest.get(
+      Routes.applicationGuildCommands(clientId, guild.id)
+    )) as unknown[];
+    if (existing.length === 0) {
+      continue;
+    }
+    await rest.put(Routes.applicationGuildCommands(clientId, guild.id), { body: [] });
+    cleared += 1;
+  }
+  return cleared;
+}
+
 export async function registerCommands() {
   const rest = new REST({ version: '10' }).setToken(env.BOT_TOKEN);
-  const body = [
-    ...commands.map((c) => c.data.toJSON()),
-    ...utilityContextMenus.map((c) => c.data.toJSON())
-  ];
+  const body = buildCommandBody();
 
   // Guild commands sync instantly; global can take up to ~1h.
   if (env.BOT_GUILD_ID) {
     await rest.put(Routes.applicationGuildCommands(env.BOT_CLIENT_ID, env.BOT_GUILD_ID), {
       body
     });
+    // Remove global copies so the guild does not show every command twice.
+    await rest.put(Routes.applicationCommands(env.BOT_CLIENT_ID), { body: [] });
     logger.info(
       {
         scope: 'guild',
         guildId: env.BOT_GUILD_ID,
-        count: commands.length,
-        contextMenus: utilityContextMenus.length
+        count: body.length,
+        clearedGlobal: true
       },
-      'Registered guild application commands'
+      'Registered guild application commands and cleared global commands'
     );
     return;
   }
 
   await rest.put(Routes.applicationCommands(env.BOT_CLIENT_ID), { body });
+
+  // Wipe leftover guild-scoped registrations from earlier BOT_GUILD_ID / shard runs.
+  let clearedGuilds = 0;
+  try {
+    clearedGuilds = await clearGuildCommandLeftovers(rest, env.BOT_CLIENT_ID);
+  } catch (error) {
+    logger.warn({ error }, 'Failed to clear leftover guild application commands');
+  }
+
   logger.info(
     {
       scope: 'global',
-      count: commands.length,
-      contextMenus: utilityContextMenus.length
+      count: body.length,
+      clearedGuilds
     },
-    'Registered global application commands'
+    'Registered global application commands and cleared guild-scoped leftovers'
   );
 }