diff --git a/Overlord-Client/cmd/agent/session.go b/Overlord-Client/cmd/agent/session.go
index fad2b3e..29bd4c7 100644
--- a/Overlord-Client/cmd/agent/session.go
+++ b/Overlord-Client/cmd/agent/session.go
@@ -469,6 +469,38 @@ func getPingInterval() time.Duration {
 	return time.Duration(ms) * time.Millisecond
 }
 
+func classifySessionError(err error) (reason, detail string) {
+	if err == nil {
+		return "crash", ""
+	}
+	msg := err.Error()
+	msgLower := strings.ToLower(msg)
+	if strings.Contains(msgLower, "panic") {
+		return "panic", truncateStr(msg, 300)
+	}
+	var closeErr *websocket.CloseError
+	if errors.As(err, &closeErr) {
+		if closeErr.Code == websocket.StatusNormalClosure || closeErr.Code == websocket.StatusGoingAway {
+			return "normal", ""
+		}
+		return "network", fmt.Sprintf("ws close code=%d reason=%s", closeErr.Code, truncateStr(closeErr.Reason, 100))
+	}
+	if strings.Contains(msgLower, "timed out from inactivity") || strings.Contains(msgLower, "pong timeout") {
+		return "timeout", truncateStr(msg, 300)
+	}
+	if strings.Contains(msgLower, "context canceled") || strings.Contains(msgLower, "context deadline exceeded") {
+		return "normal", ""
+	}
+	return "network", truncateStr(msg, 300)
+}
+
+func truncateStr(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n] + "…"
+}
+
 func runSession(ctx context.Context, cancel context.CancelFunc, conn *websocket.Conn, cfg config.Config) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
@@ -480,7 +512,14 @@ func runSession(ctx context.Context, cancel context.CancelFunc, conn *websocket.
 		}
 	}()
 	defer cancel()
-	defer conn.Close(websocket.StatusNormalClosure, "bye")
+	defer func() {
+		reason, detail := classifySessionError(err)
+		di := wire.DisconnectInfo{Type: "disconnect_info", Reason: reason, Detail: detail}
+		sendCtx, sendCancel := context.WithTimeout(context.Background(), 2*time.Second)
+		defer sendCancel()
+		_ = wire.WriteMsg(sendCtx, conn, di)
+		conn.Close(websocket.StatusNormalClosure, "bye")
+	}()
 
 	identity := config.DeriveIdentity()
 	log.Printf("[purgatory] identity fingerprint=%s", identity.Fingerprint)
diff --git a/Overlord-Client/cmd/agent/wire/protocol.go b/Overlord-Client/cmd/agent/wire/protocol.go
index 4e2f0f7..a8f129c 100644
--- a/Overlord-Client/cmd/agent/wire/protocol.go
+++ b/Overlord-Client/cmd/agent/wire/protocol.go
@@ -248,3 +248,9 @@ type ProxyClose struct {
 	Type         string `msgpack:"type"`
 	ConnectionID string `msgpack:"connectionId"`
 }
+
+type DisconnectInfo struct {
+	Type   string `msgpack:"type"`
+	Reason string `msgpack:"reason"`           // "normal", "panic", "crash", "network", "timeout"
+	Detail string `msgpack:"detail,omitempty"` // error message
+}
diff --git a/Overlord-Server/public/assets/main.css b/Overlord-Server/public/assets/main.css
index d01b43b..ebc4511 100644
--- a/Overlord-Server/public/assets/main.css
+++ b/Overlord-Server/public/assets/main.css
@@ -2184,6 +2184,7 @@ body.sb-collapsed .sb-collapse-btn i {
 body.sb-collapsed .sb-link {
   justify-content: center;
   padding: 12px 0;
+  gap: 0;
 }
 .sb-icon {
   flex-shrink: 0;
diff --git a/Overlord-Server/public/assets/render.js b/Overlord-Server/public/assets/render.js
index 726ba13..fda69a4 100644
--- a/Overlord-Server/public/assets/render.js
+++ b/Overlord-Server/public/assets/render.js
@@ -266,6 +266,14 @@ export function createRenderer({
               <i class="fa-solid fa-circle"></i>
               ${client.online ? "Online" : "Offline"}
             </span>
+            ${!client.online && client.disconnectReason && client.disconnectReason !== "normal" ? (() => {
+              const iconMap = { panic: "fa-skull-crossbones", crash: "fa-skull", timeout: "fa-clock", network: "fa-plug-circle-xmark" };
+              const colorMap = { panic: "text-red-400", crash: "text-red-400", timeout: "text-amber-400", network: "text-slate-400" };
+              const icon = iconMap[client.disconnectReason] || "fa-circle-exclamation";
+              const color = colorMap[client.disconnectReason] || "text-slate-400";
+              const detail = client.disconnectDetail ? escapeHtml(client.disconnectDetail) : "";
+              return `<span class="pill pill-ghost text-xs ${color}" ${detail ? `title="${detail}"` : ""}><i class="fa-solid ${icon}"></i> ${escapeHtml(client.disconnectReason)}</span>`;
+            })() : ""}
           </div>
           ${hasTagNote ? `<div class="client-tag-note rounded-lg border border-amber-900/60 bg-amber-950/20 px-3 py-2 text-sm text-amber-100 whitespace-pre-wrap break-words max-h-48 overflow-auto ${isTagNoteExpanded ? "" : "hidden"}">${escapeHtml(customTagNote)}</div>` : ""}
           <div class="flex items-center gap-2 flex-wrap text-sm text-slate-300">
diff --git a/Overlord-Server/src/db.ts b/Overlord-Server/src/db.ts
index 902921c..bcb9a18 100644
--- a/Overlord-Server/src/db.ts
+++ b/Overlord-Server/src/db.ts
@@ -97,6 +97,12 @@ db.run(
 db.run(
   `CREATE INDEX IF NOT EXISTS idx_clients_ping_ms ON clients(ping_ms);`,
 );
+try {
+  db.run(`ALTER TABLE clients ADD COLUMN disconnect_reason TEXT`);
+} catch {}
+try {
+  db.run(`ALTER TABLE clients ADD COLUMN disconnect_detail TEXT`);
+} catch {}
 
 db.run(`
   CREATE TABLE IF NOT EXISTS banned_ips (
@@ -304,13 +310,22 @@ export function upsertClientRow(
   }
 }
 
-export function setOnlineState(id: string, online: boolean) {
-  db.run(
-    `UPDATE clients SET online=?, last_seen=? WHERE id=?`,
-    online ? 1 : 0,
-    Date.now(),
-    id,
-  );
+export function setOnlineState(id: string, online: boolean, disconnectReason?: string, disconnectDetail?: string) {
+  if (online) {
+    db.run(
+      `UPDATE clients SET online=1, last_seen=?, disconnect_reason=NULL, disconnect_detail=NULL WHERE id=?`,
+      Date.now(),
+      id,
+    );
+  } else {
+    db.run(
+      `UPDATE clients SET online=0, last_seen=?, disconnect_reason=?, disconnect_detail=? WHERE id=?`,
+      Date.now(),
+      disconnectReason ?? null,
+      disconnectDetail ?? null,
+      id,
+    );
+  }
 }
 
 export function deleteClientRow(id: string) {
@@ -541,7 +556,7 @@ export function listClients(filters: ListFilters): ListResult {
 
   const rows = db
     .query<any>(
-      `SELECT id, hwid, role, host, os, arch, version, user, nickname, custom_tag as customTag, custom_tag_note as customTagNote, monitors, country, last_seen as lastSeen, online, ping_ms as pingMs, bookmarked, enrollment_status as enrollmentStatus, public_key as publicKey, key_fingerprint as keyFingerprint, cpu, gpu, ram
+      `SELECT id, hwid, role, host, os, arch, version, user, nickname, custom_tag as customTag, custom_tag_note as customTagNote, monitors, country, last_seen as lastSeen, online, ping_ms as pingMs, bookmarked, enrollment_status as enrollmentStatus, public_key as publicKey, key_fingerprint as keyFingerprint, cpu, gpu, ram, disconnect_reason as disconnectReason, disconnect_detail as disconnectDetail
        FROM clients
        ${whereSql}
        ${orderBy}
@@ -573,6 +588,8 @@ export function listClients(filters: ListFilters): ListResult {
     cpu: c.cpu || null,
     gpu: c.gpu || null,
     ram: c.ram || null,
+    disconnectReason: c.disconnectReason || null,
+    disconnectDetail: c.disconnectDetail || null,
     thumbnail: getThumbnail(c.id),
   }));
 
diff --git a/Overlord-Server/src/server/routes/websocket-lifecycle-routes.ts b/Overlord-Server/src/server/routes/websocket-lifecycle-routes.ts
index ff42802..225c9eb 100644
--- a/Overlord-Server/src/server/routes/websocket-lifecycle-routes.ts
+++ b/Overlord-Server/src/server/routes/websocket-lifecycle-routes.ts
@@ -555,6 +555,16 @@ export async function handleWebSocketMessage(
         }
         break;
       }
+      case "disconnect_info": {
+        const reason = typeof (payload as any).reason === "string" ? (payload as any).reason : "";
+        const detail = typeof (payload as any).detail === "string" ? (payload as any).detail : "";
+        if (reason) {
+          ws.data.disconnectReason = reason;
+          ws.data.disconnectDetail = detail || undefined;
+          logger.debug(`[disconnect_info] ${client.id} reason=${reason}`);
+        }
+        break;
+      }
       default:
         break;
     }
@@ -709,15 +719,18 @@ export function handleWebSocketClose(
     });
   }
 
+  const storedDisconnectReason = ws.data.disconnectReason;
+  const storedDisconnectDetail = ws.data.disconnectDetail;
+
   clientManager.deleteClient(clientId);
   stopAllProxiesForClient(clientId);
   clearClientSyncState(clientId);
   deps.notifyConsoleClosed(clientId, "Client disconnected");
-  setOnlineState(clientId, false);
+  setOnlineState(clientId, false, storedDisconnectReason, storedDisconnectDetail);
   deps.clearPendingNotificationScreenshots(clientId);
   deps.clearClientPluginState(clientId);
   deps.notifyDashboard();
-  logger.info(`[close] ${clientId} code=${code} reason=${reason}`);
+  logger.info(`[close] ${clientId} code=${code} reason=${reason} disconnect_reason=${storedDisconnectReason || "unknown"}`);
 
   if (role === "client") {
     deps.notifyRemoteDesktopStatus(clientId, "offline", "Client disconnected");
@@ -729,7 +742,7 @@ export function handleWebSocketClose(
       action: AuditAction.CLIENT_DISCONNECT,
       targetClientId: clientId,
       success: true,
-      details: JSON.stringify({ code, reason: String(reason || "") }),
+      details: JSON.stringify({ code, reason: String(reason || ""), disconnectReason: storedDisconnectReason || null }),
     });
   }
 }
diff --git a/Overlord-Server/src/sessions/types.ts b/Overlord-Server/src/sessions/types.ts
index 1ba7e89..90871fd 100644
--- a/Overlord-Server/src/sessions/types.ts
+++ b/Overlord-Server/src/sessions/types.ts
@@ -24,6 +24,8 @@ export type SocketData = {
   autoTasksRan?: boolean;
   autoDeploysRan?: boolean;
   enrollmentNonce?: string;
+  disconnectReason?: string;
+  disconnectDetail?: string;
 };
 
 export type ConsoleSession = {
diff --git a/Overlord-Server/src/types.ts b/Overlord-Server/src/types.ts
index f02e2d7..79e4cb0 100644
--- a/Overlord-Server/src/types.ts
+++ b/Overlord-Server/src/types.ts
@@ -31,6 +31,8 @@ export type ClientInfo = {
   enrollmentStatus?: EnrollmentStatus;
   publicKey?: string;
   keyFingerprint?: string;
+  disconnectReason?: string;
+  disconnectDetail?: string;
 };
 
 export type ListFilters = {
diff --git a/Overlord-Server/src/wsValidation.ts b/Overlord-Server/src/wsValidation.ts
index 585b258..710a36d 100644
--- a/Overlord-Server/src/wsValidation.ts
+++ b/Overlord-Server/src/wsValidation.ts
@@ -32,6 +32,7 @@ export const ALLOWED_CLIENT_MESSAGE_TYPES = new Set([
   "clipboard_content",
   "proxy_data",
   "proxy_close",
+  "disconnect_info",
 ]);
 
 export function isAllowedClientMessageType(type: string): boolean {