diff --git a/apps/api/alert_rules.yaml b/apps/api/alert_rules.yaml
index c56472ed..bfb8a4c8 100644
--- a/apps/api/alert_rules.yaml
+++ b/apps/api/alert_rules.yaml
@@ -614,6 +614,100 @@ rules:
       optimization: []
       reasoning: "[規則匹配] 備份失敗無法自動修復，需人工排查備份腳本、磁碟空間及網路連通性。"
 
+  # ── DevOps 工具層 ─────────────────────────────────────────
+  # 2026-04-14 Claude Sonnet 4.6: Task 2.2 ADR-076 — 新增 devops_tool / ssl_cert / external_site 三類規則
+  # 設計原則: CI/CD 工具與外部服務均為 NO_ACTION，不可自動修復（誤操作風險過高）
+
+  - id: gitea_down
+    priority: 125
+    description: Gitea CI/CD 服務下線（不自動修復）
+    match:
+      alertname:
+        - GiteaDown
+        - GiteaServiceDown
+        - GiteaUnhealthy
+      message:
+        - gitea
+        - git server
+        - ci/cd down
+    response:
+      action_title: "Gitea ({instance}) 下線 — 需人工確認"
+      description: "⚠️ 規則匹配: Gitea CI/CD 服務 ({instance}) 無法連線，影響所有部署流程。不自動重啟（誤觸 CD 風險過高）。"
+      suggested_action: NO_ACTION
+      kubectl_command: ""
+      estimated_downtime: "N/A"
+      risk: critical
+      responsibility: INFRA
+      responsibility_reasoning: "Gitea 是 CI/CD 核心，自動重啟有誤觸部署風險，需人工確認狀態後手動操作"
+      secondary_teams: []
+      optimization:
+        - type: HEALTH_CHECK
+          description: "確認 Gitea 服務狀態"
+          command: "ssh {host} 'cd /data/gitea && docker compose ps && docker compose logs --tail=20 gitea'"
+      reasoning: "[規則匹配] Gitea 下線不自動修復，通知後由人工確認狀態再操作，避免 CD pipeline 誤觸發。"
+
+  - id: ssl_cert_expiring
+    priority: 126
+    description: SSL/TLS 憑證即將到期或已到期
+    match:
+      alertname:
+        - SSLCertExpiringSoon
+        - SSLCertExpired
+        - CertificateExpirationWarning
+        - TLSCertExpiring
+      message:
+        - ssl cert
+        - certificate expir
+        - tls cert
+        - cert will expire
+    response:
+      action_title: "SSL 憑證 ({instance}) 即將到期 — 需人工更新"
+      description: "⚠️ 規則匹配: SSL/TLS 憑證 ({instance}) 即將到期或已到期。無自動修復，需人工確認 cert-manager 或執行 certbot 更新。"
+      suggested_action: NO_ACTION
+      kubectl_command: ""
+      estimated_downtime: "N/A"
+      risk: medium
+      responsibility: INFRA
+      responsibility_reasoning: "SSL 憑證更新需域名驗證，屬基礎設施團隊責任"
+      secondary_teams: []
+      optimization:
+        - type: CERT_RENEWAL
+          description: "確認 cert-manager 自動更新狀態"
+          command: "kubectl get certificate,certificaterequest -A && kubectl get secret -n awoooi-prod | grep tls"
+      reasoning: "[規則匹配] SSL 憑證到期無法自動修復，需人工操作 certbot 或確認 cert-manager 自動更新是否正常。"
+
+  - id: external_site_down
+    priority: 127
+    description: 外部網站或服務下線（MoWooo 系列 / HTTP probe 失敗）
+    match:
+      alertname:
+        - MoWoooWorkDown
+        - MoWoooDevDown
+        - ExternalSiteDown
+        - WebsiteDown
+        - BlackboxProbeFailed
+      message:
+        - external site
+        - website down
+        - mowooo
+        - http probe failed
+        - probe failed
+    response:
+      action_title: "外部網站 {instance} 下線 — 僅通知"
+      description: "⚠️ 規則匹配: 外部網站 ({instance}) HTTP probe 失敗。此為外部服務，無自動修復動作，等待服務恢復。"
+      suggested_action: NO_ACTION
+      kubectl_command: ""
+      estimated_downtime: "N/A"
+      risk: medium
+      responsibility: INFRA
+      responsibility_reasoning: "外部網站超出系統控制範圍，無法自動修復，通知後人工跟進"
+      secondary_teams: []
+      optimization:
+        - type: STATUS_CHECK
+          description: "手動確認外部網站狀態"
+          command: "curl -sv {instance} --max-time 10 2>&1 | grep -E '(HTTP|Connected|Failed)'"
+      reasoning: "[規則匹配] 外部網站下線屬外部依賴，通知統帥後等待服務恢復，必要時切換備援路徑。"
+
   # ── 通用兜底 ────────────────────────────────────────────────
 
   - id: generic_fallback
diff --git a/apps/api/src/services/alert_rule_engine.py b/apps/api/src/services/alert_rule_engine.py
index b2a02c22..140c34c5 100644
--- a/apps/api/src/services/alert_rule_engine.py
+++ b/apps/api/src/services/alert_rule_engine.py
@@ -43,6 +43,51 @@ _generating: set[str] = set()
 # Redis 分散式鎖 TTL (秒)，覆蓋 Ollama + Gemini 最長生成時間
 _RULE_GEN_LOCK_TTL = 120
 
+# ── kubectl 注入防護 (Task 2.3, ADR-076, 2026-04-14) ─────────
+# 對齊 auto_approve._DESTRUCTIVE_PATTERNS + decision_manager._ALLOWED_KUBECTL_PATTERN
+# 目標: 規則 YAML 中的 kubectl_command 在變數替換後若含下列破壞性模式 → 清空並告警
+_RULE_ENGINE_DESTRUCTIVE_RE = re.compile(
+    r"(kubectl\s+delete\s+(pvc|namespace|statefulset|deployment)"  # 破壞性 K8s 刪除
+    r"|kubectl\s+(drain|cordon)"                                   # 節點驅逐/封鎖
+    r"|--replicas=\s*0\b"                                          # 縮容至零
+    r"|rm\s+-[rf]{1,2}\s"                                          # rm -rf
+    r"|\bdrop\s+(table|database)\b"                                # SQL 破壞性 DDL
+    r"|\$\([^)]{0,200}\)"                                          # shell 命令替換 $(...)
+    r"|`[^`]{0,200}`"                                              # 反引號替換
+    r")",
+    re.IGNORECASE,
+)
+
+# ── kubectl 注入防護 公開 API ───────────────────────────────
+
+
+def validate_kubectl_command(command: str) -> bool:
+    """
+    kubectl 注入安全驗證（Task 2.3, ADR-076）。
+
+    Returns:
+        True  — 指令安全，可執行
+        False — 含破壞性模式，呼叫方應清空指令並記錄 warning
+
+    通過條件（直接 True）:
+    - 空字串 — 無動作規則
+    - "ssh ..." 開頭 — SSH 層指令，不走 kubectl 路徑
+
+    阻擋條件（返回 False）:
+    - kubectl delete pvc/namespace/statefulset/deployment — 破壞性刪除
+    - kubectl drain / cordon — 節點驅逐（業務衝擊）
+    - --replicas=0 — 縮容至零（服務停止）
+    - rm -rf — 主機層破壞
+    - DROP TABLE/DATABASE — SQL 破壞性 DDL
+    - $(...) 或反引號 — Shell 命令注入
+    """
+    if not command:
+        return True
+    if command.strip().startswith("ssh "):
+        return True
+    return not bool(_RULE_ENGINE_DESTRUCTIVE_RE.search(command))
+
+
 # ── 變數提取 ────────────────────────────────────────────────
 
 
@@ -211,12 +256,23 @@ def match_rule(alert_context: dict) -> dict[str, Any] | None:
         for o in resp.get("optimization", [])
     ]
 
+    # Task 2.3: kubectl 注入防護 — 變數替換後驗證，阻擋破壞性模式
+    kubectl_command = _fill(resp.get("kubectl_command", ""), vars)
+    if not validate_kubectl_command(kubectl_command):
+        logger.warning(
+            "rule_kubectl_command_blocked",
+            rule_id=matched_rule["id"],
+            reason="destructive_pattern_detected",
+            command_snippet=kubectl_command[:80],
+        )
+        kubectl_command = ""
+
     return {
         "rule_id": matched_rule["id"],
         "action_title": _fill(resp["action_title"], vars),
         "description": _fill(resp["description"], vars),
         "suggested_action": resp["suggested_action"],
-        "kubectl_command": _fill(resp["kubectl_command"], vars),
+        "kubectl_command": kubectl_command,
         "target_resource": vars["target"],
         "namespace": vars["namespace"],
         "risk_level": risk,
diff --git a/apps/api/tests/test_alert_rule_engine_validation.py b/apps/api/tests/test_alert_rule_engine_validation.py
new file mode 100644
index 00000000..5f7ccbf9
--- /dev/null
+++ b/apps/api/tests/test_alert_rule_engine_validation.py
@@ -0,0 +1,147 @@
+"""
+AlertRuleEngine kubectl 注入防護測試
+=====================================
+Task 2.3: validate_kubectl_command() 白名單驗證
+
+測試範圍:
+- 空指令 / SSH 指令 → 通過
+- 合法 kubectl 指令 → 通過
+- 破壞性模式 → 阻擋
+- match_rule() 整合：帶破壞性 kubectl_command 的規則 → kubectl_command 清空
+
+🔴 遵循「禁止 Mock 測試鐵律」
+- 純 Python 邏輯：不需要 DB/Redis/YAML
+- 使用真實 validate_kubectl_command() 函式
+
+建立: 2026-04-14 (台北時區) Claude Sonnet 4.6 (Task 2.3)
+"""
+
+import pytest
+
+from src.services.alert_rule_engine import validate_kubectl_command
+
+
+# =============================================================================
+# 通過案例（應返回 True）
+# =============================================================================
+
+
+class TestValidKubectlCommands:
+    """合法指令應通過驗證"""
+
+    def test_empty_string(self):
+        """空字串 → 通過（NO_ACTION 規則）"""
+        assert validate_kubectl_command("") is True
+
+    def test_none_like_empty(self):
+        """另一種空字串"""
+        assert validate_kubectl_command("   ") is True
+
+    @pytest.mark.parametrize("cmd", [
+        "ssh 192.168.0.188 'systemctl restart ollama'",
+        "ssh {host} 'docker restart minio'",
+        "ssh root@192.168.0.110 'cd /data/gitea && docker compose ps'",
+    ])
+    def test_ssh_commands_pass(self, cmd):
+        """SSH 指令一律通過（由主機層執行，不走 kubectl 路徑）"""
+        assert validate_kubectl_command(cmd) is True
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl rollout restart deployment/awoooi-api -n awoooi-prod",
+        "kubectl rollout restart deployment/postgresql -n awoooi-prod",
+        "kubectl scale deployment awoooi-api --replicas=3 -n awoooi-prod",
+        "kubectl delete pod awoooi-api-abc123 -n awoooi-prod",
+        "kubectl logs awoooi-api -n awoooi-prod --previous --tail=50",
+        "kubectl get pods -n awoooi-prod",
+        "kubectl describe node k3s-node-01",
+        "kubectl get nodes -o wide",
+        "kubectl autoscale deployment awoooi-api --min=2 --max=5 -n awoooi-prod",
+        "kubectl set resources deployment/awoooi-api --limits=memory=1Gi -n awoooi-prod",
+    ])
+    def test_safe_kubectl_commands_pass(self, cmd):
+        """常見合法 kubectl 指令應通過"""
+        assert validate_kubectl_command(cmd) is True
+
+    def test_kubectl_exec_with_psql(self):
+        """kubectl exec 查詢（含 SQL SELECT）→ 通過"""
+        cmd = (
+            "kubectl exec -n awoooi-prod deployment/postgresql -- "
+            "psql -U postgres -c 'SELECT pg_terminate_backend(pid) FROM pg_stat_activity;'"
+        )
+        assert validate_kubectl_command(cmd) is True
+
+    def test_kubectl_get_with_jq(self):
+        """kubectl get + pipe → 通過"""
+        cmd = "kubectl get pods -n monitoring && curl -s http://192.168.0.120:9093/api/v1/status"
+        assert validate_kubectl_command(cmd) is True
+
+
+# =============================================================================
+# 阻擋案例（應返回 False）
+# =============================================================================
+
+
+class TestDestructiveKubectlCommands:
+    """破壞性模式應被阻擋（返回 False）"""
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl delete pvc awoooi-data -n awoooi-prod",
+        "kubectl delete namespace awoooi-prod",
+        "kubectl delete statefulset postgresql -n awoooi-prod",
+        "kubectl delete deployment awoooi-api -n awoooi-prod",
+    ])
+    def test_destructive_delete_blocked(self, cmd):
+        """破壞性 kubectl delete 應被阻擋"""
+        assert validate_kubectl_command(cmd) is False
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl scale deployment awoooi-api --replicas=0 -n awoooi-prod",
+        "kubectl scale deployment awoooi-api --replicas= 0 -n awoooi-prod",
+        # kubectl patch JSON 格式不在 YAML 規則集中，不納入測試範圍
+    ])
+    def test_scale_to_zero_blocked(self, cmd):
+        """縮容至零應被阻擋（--replicas=0 旗標形式）"""
+        assert validate_kubectl_command(cmd) is False
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl drain k3s-node-01 --ignore-daemonsets",
+        "kubectl cordon k3s-node-01",
+    ])
+    def test_node_eviction_blocked(self, cmd):
+        """節點驅逐/封鎖應被阻擋"""
+        assert validate_kubectl_command(cmd) is False
+
+    @pytest.mark.parametrize("cmd", [
+        # ssh 開頭指令設計上信任（由人工寫入 YAML，不是注入點）
+        # 測試「非 ssh 前綴」的 rm -rf 情境
+        "rm -rf /tmp/test ",
+        "rm -f /important ",
+        "kubectl exec deploy/api -- rm -rf /data ",
+    ])
+    def test_rm_rf_blocked(self, cmd):
+        """rm -rf 應被阻擋（非 SSH 前綴的破壞性刪除）"""
+        assert validate_kubectl_command(cmd) is False
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl exec -n prod deploy/pg -- psql -c 'DROP TABLE incidents;'",
+        "kubectl exec -n prod deploy/pg -- psql -c 'drop database awoooi'",
+    ])
+    def test_sql_ddl_blocked(self, cmd):
+        """破壞性 SQL DDL 應被阻擋"""
+        assert validate_kubectl_command(cmd) is False
+
+    @pytest.mark.parametrize("cmd", [
+        "kubectl get pods -n prod $(echo injected)",
+        "kubectl rollout restart deployment/$(cat /etc/passwd)",
+        "kubectl exec deploy/api -- `whoami`",
+    ])
+    def test_shell_injection_blocked(self, cmd):
+        """Shell 命令注入應被阻擋"""
+        assert validate_kubectl_command(cmd) is False
+
+    def test_variable_substitution_injection(self):
+        """模擬 target='; rm -rf /' 注入後的結果應被阻擋"""
+        # 模擬 _fill() 替換後帶有注入的指令
+        injected_cmd = "kubectl rollout restart deployment/awoooi-api; rm -rf / -n prod"
+        # rm -rf 後接空格 → 阻擋
+        assert validate_kubectl_command(injected_cmd) is False