diff --git a/convex/liveChat.ts b/convex/liveChat.ts
index 1468d96..d24eac1 100644
--- a/convex/liveChat.ts
+++ b/convex/liveChat.ts
@@ -103,6 +103,42 @@ export const startSession = mutation({
 
     const now = Date.now()
 
+    // Calcular não lidas iniciais: mensagens do ticket após a última sessão encerrada
+    // que não foram enviadas pela própria máquina/usuário vinculado.
+    const lastEndedSession = await ctx.db
+      .query("liveChatSessions")
+      .withIndex("by_ticket", (q) => q.eq("ticketId", ticketId))
+      .filter((q) => q.eq(q.field("status"), "ENDED"))
+      .collect()
+      .then((sessions) =>
+        sessions.reduce(
+          (latest, current) =>
+            !latest || (current.endedAt ?? 0) > (latest.endedAt ?? 0) ? current : latest,
+          null as typeof sessions[number] | null
+        )
+      )
+
+    const cutoff = lastEndedSession?.endedAt ?? 0
+
+    const machineUserIds = [
+      machine.assignedUserId,
+      ...(machine.linkedUserIds ?? []),
+      ticket.requesterId,
+    ]
+      .filter(Boolean)
+      .map((id) => id!.toString())
+
+    const unreadByMachine = await ctx.db
+      .query("ticketChatMessages")
+      .withIndex("by_ticket_created", (q) => q.eq("ticketId", ticketId))
+      .collect()
+      .then((messages) =>
+        messages.filter((msg) => {
+          if (msg.createdAt <= cutoff) return false
+          return !machineUserIds.includes(msg.authorId.toString())
+        }).length
+      )
+
     // Criar nova sessao
     const sessionId = await ctx.db.insert("liveChatSessions", {
       tenantId: ticket.tenantId,
@@ -117,7 +153,7 @@ export const startSession = mutation({
       status: "ACTIVE",
       startedAt: now,
       lastActivityAt: now,
-      unreadByMachine: 0,
+      unreadByMachine,
       unreadByAgent: 0,
     })