diff --git a/server/status.py b/server/status.py
index 644efbe..85f4ea6 100644
--- a/server/status.py
+++ b/server/status.py
@@ -69,6 +69,28 @@ def _is_host_mode_request() -> bool:
     return bool(session.get("host_mode")) and (TERMINAL_SANDBOX_MODE or "").lower() == "host"
 
 
+@status_bp.route('/api/health')
+@api_login_required
+def get_health():
+    """轻量健康检查：用于前端连接心跳，避免触发重型 status 计算。"""
+    started_at = time.perf_counter()
+    heartbeat_id = request.headers.get("X-Connection-Heartbeat", "").strip()
+    username = session.get("username") or "-"
+    payload = {
+        "success": True,
+        "status": "ok",
+        "server_time_ms": int(time.time() * 1000),
+    }
+    elapsed_ms = (time.perf_counter() - started_at) * 1000
+    if request.args.get("diag") == "1" or elapsed_ms >= 800:
+        log_conn_diag(
+            f"health hb={heartbeat_id or '-'} user={username} "
+            f"elapsed_ms={elapsed_ms:.1f} host_mode={bool(session.get('host_mode'))} "
+            f"workspace_id={session.get('workspace_id') or '-'}"
+        )
+    return jsonify(payload)
+
+
 @status_bp.route('/api/status')
 @api_login_required
 @with_terminal
diff --git a/static/src/app/methods/ui.ts b/static/src/app/methods/ui.ts
index 60908ce..1dba2f6 100644
--- a/static/src/app/methods/ui.ts
+++ b/static/src/app/methods/ui.ts
@@ -2025,18 +2025,32 @@ export const uiMethods = {
   },
 
   async checkConnectionHealth() {
+    if (this.connectionHeartbeatInFlight) {
+      connectionDiag('log', 'health-skip-inflight', {
+        seq: this.connectionHeartbeatSeq,
+        isConnected: !!this.isConnected,
+        failCount: this.connectionHeartbeatFailCount
+      });
+      return;
+    }
+    this.connectionHeartbeatInFlight = true;
     const seq = Number(this.connectionHeartbeatSeq || 0) + 1;
     this.connectionHeartbeatSeq = seq;
     const requestId = `${Date.now()}-${seq}`;
     const startedAt = Date.now();
     const diagEnabled = isConnectionDiagEnabled();
-    const statusUrl = diagEnabled ? '/api/status?diag=1' : '/api/status';
+    const healthUrl = diagEnabled ? '/api/health?diag=1' : '/api/health';
     const wasConnected = !!this.isConnected;
     let responseStatus: number | null = null;
     const controller = typeof AbortController !== 'undefined' ? new AbortController() : null;
-    const timeoutId = controller ? window.setTimeout(() => controller.abort(), 5000) : null;
+    const timeoutMs =
+      typeof this.connectionHeartbeatRequestTimeoutMs === 'number' &&
+      this.connectionHeartbeatRequestTimeoutMs > 0
+        ? this.connectionHeartbeatRequestTimeoutMs
+        : 5000;
+    const timeoutId = controller ? window.setTimeout(() => controller.abort(), timeoutMs) : null;
     try {
-      const response = await fetch(statusUrl, {
+      const response = await fetch(healthUrl, {
         method: 'GET',
         cache: 'no-store',
         headers: {
@@ -2066,6 +2080,7 @@ export const uiMethods = {
             failCountBeforeRecover,
             status: responseStatus,
             diagEnabled,
+            endpoint: healthUrl,
             conversationId: this.currentConversationId || null,
             taskInProgress: !!this.taskInProgress,
             streamingMessage: !!this.streamingMessage,
@@ -2083,6 +2098,7 @@ export const uiMethods = {
           seq,
           elapsedMs: this.connectionHeartbeatLastLatencyMs,
           status: responseStatus,
+          endpoint: healthUrl,
           visibility: document?.visibilityState || 'unknown'
         });
       }
@@ -2094,12 +2110,20 @@ export const uiMethods = {
       const errName = error?.name || 'Error';
       const errMessage = error?.message || String(error);
       this.connectionHeartbeatLastError = `${errName}: ${errMessage}`;
-      // 一次失败就先置灰，避免“服务已断但常亮绿色”的误导
-      this.isConnected = false;
-      if (wasConnected) {
+      const failThreshold =
+        typeof this.connectionHeartbeatFailThreshold === 'number' &&
+        this.connectionHeartbeatFailThreshold > 0
+          ? this.connectionHeartbeatFailThreshold
+          : 3;
+      const shouldDisconnect = nextFailCount >= failThreshold;
+      // 改为连续失败阈值后再置灰，避免偶发请求超时导致“假断连”
+      if (shouldDisconnect) {
+        this.isConnected = false;
+      }
+      if (wasConnected && shouldDisconnect) {
         this.connectionHeartbeatLastChangeAt = Date.now();
       }
-      const shouldLogFail = wasConnected || nextFailCount <= 3 || nextFailCount % 10 === 0;
+      const shouldLogFail = wasConnected || nextFailCount <= failThreshold || nextFailCount % 10 === 0;
       connectionDiag(
         shouldLogFail ? 'warn' : 'log',
         'health-failed',
@@ -2109,9 +2133,12 @@ export const uiMethods = {
           elapsedMs: this.connectionHeartbeatLastLatencyMs,
           failCount: nextFailCount,
           status: responseStatus,
+          endpoint: healthUrl,
           diagEnabled,
           wasConnected,
           nowConnected: !!this.isConnected,
+          failThreshold,
+          shouldDisconnect,
           errorName: errName,
           errorMessage: errMessage,
           timeout: errName === 'AbortError',
@@ -2125,6 +2152,7 @@ export const uiMethods = {
         { force: shouldLogFail }
       );
     } finally {
+      this.connectionHeartbeatInFlight = false;
       if (timeoutId) {
         clearTimeout(timeoutId);
       }
diff --git a/static/src/app/state.ts b/static/src/app/state.ts
index 76b298f..d2e60b2 100644
--- a/static/src/app/state.ts
+++ b/static/src/app/state.ts
@@ -144,6 +144,9 @@ export function dataState() {
     connectionHeartbeatLastError: '',
     connectionHeartbeatLastStatusCode: null,
     connectionHeartbeatLastChangeAt: 0,
+    connectionHeartbeatInFlight: false,
+    connectionHeartbeatFailThreshold: 3,
+    connectionHeartbeatRequestTimeoutMs: 5000,
     connectionHeartbeatIntervalMs: 8000,
     connectionHeartbeatDisconnectedIntervalMs: 1000,