diff --git a/.github/workflows/nightly-llm.yaml b/.github/workflows/nightly-llm.yaml
new file mode 100644
index 00000000..8e4492d4
--- /dev/null
+++ b/.github/workflows/nightly-llm.yaml
@@ -0,0 +1,89 @@
+# =============================================================================
+# AWOOOI Nightly LLM Tests (2026-03-26)
+# =============================================================================
+# 🤖 完整 LLM 測試 - 每日執行 (CPU 推理需 ~45 分鐘)
+#
+# 測試內容:
+# - test_model_regression.py: 模型回歸測試 (4 案例)
+# - test_prompt_validation.py: Prompt 品質驗證 (5 案例)
+#
+# 觸發時機:
+# - 每日 00:00 UTC (08:00 台北)
+# - 手動觸發
+
+name: Nightly LLM Tests
+
+on:
+  schedule:
+    - cron: '0 0 * * *'  # 每日 00:00 UTC (08:00 台北)
+  workflow_dispatch:
+    inputs:
+      timeout:
+        description: 'Timeout per test (seconds)'
+        required: false
+        default: '300'
+
+concurrency:
+  group: nightly-llm
+  cancel-in-progress: true
+
+env:
+  PYTHON_VERSION: '3.11'
+  OLLAMA_URL: http://192.168.0.188:11434
+  OLLAMA_MODEL: qwen2.5:7b-instruct
+
+jobs:
+  llm-regression:
+    name: LLM Regression Tests
+    runs-on: [self-hosted, harbor, k8s]
+    timeout-minutes: 60  # 1 小時超時
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v3
+
+      - name: Check Ollama
+        run: |
+          echo "🔗 檢查 Ollama 服務..."
+          if curl -s --connect-timeout 10 ${{ env.OLLAMA_URL }}/api/tags > /dev/null; then
+            echo "✅ Ollama 可用"
+            curl -s ${{ env.OLLAMA_URL }}/api/tags | python3 -c "import sys,json; [print(f'  - {m[\"name\"]}') for m in json.load(sys.stdin).get('models',[])]"
+          else
+            echo "❌ Ollama 無法連線"
+            exit 1
+          fi
+
+      - name: Model Regression Tests
+        working-directory: apps/api
+        env:
+          PYTHONPATH: ${{ github.workspace }}/apps/api
+        run: |
+          echo "🧪 執行模型回歸測試..."
+          echo "   CPU 模式: 預估 ~15-20 分鐘"
+          uv sync
+          uv run pytest tests/test_model_regression.py -v --tb=short \
+            --timeout=${{ github.event.inputs.timeout || '300' }}
+
+      - name: Prompt Validation Tests
+        working-directory: apps/api
+        env:
+          PYTHONPATH: ${{ github.workspace }}/apps/api
+        run: |
+          echo "📝 執行 Prompt 品質驗證..."
+          echo "   CPU 模式: 預估 ~20-25 分鐘"
+          uv run pytest tests/test_prompt_validation.py -v --tb=short \
+            --timeout=${{ github.event.inputs.timeout || '300' }}
+
+      - name: Summary
+        if: always()
+        run: |
+          echo "📊 Nightly LLM 測試完成"
+          echo "   Ollama: ${{ env.OLLAMA_URL }}"
+          echo "   Model: ${{ env.OLLAMA_MODEL }}"
+          echo "   Mode: CPU (no GPU)"
diff --git a/apps/api/src/core/prompts.py b/apps/api/src/core/prompts.py
new file mode 100644
index 00000000..0dc3777a
--- /dev/null
+++ b/apps/api/src/core/prompts.py
@@ -0,0 +1,174 @@
+"""
+OpenClaw System Prompts - 集中管理
+==================================
+ADR-019: System Prompt 集中管理
+
+所有 OpenClaw 相關的 System Prompt 集中在此檔案：
+1. OPENCLAW_SYSTEM_PROMPT - 生產環境完整 Prompt
+2. OPENCLAW_TEST_PROMPT - 測試用精簡 Prompt
+
+版本: v1.0
+建立: 2026-03-26 (台北時區)
+建立者: Claude Code (Phase 17 架構審查 - P2 改進)
+
+@see docs/adr/ADR-019-system-prompt-management.md (待建立)
+"""
+
+# =============================================================================
+# 生產環境 System Prompt (完整版)
+# =============================================================================
+
+OPENCLAW_SYSTEM_PROMPT = """# OpenClaw v7.1 - AWOOOI AI 仲裁官 + SignOz 視力
+
+You are OpenClaw, a senior Site Reliability Engineer (SRE) AI arbitrator with SignOz observability integration.
+
+## 🌐 Language Requirement (CRITICAL)
+- You MUST respond in **Traditional Chinese (繁體中文/正體中文)** for all text fields
+- FORBIDDEN: Simplified Chinese characters (简体字) such as: 与→與、说→說、这→這、时→時
+- Use Taiwan locale conventions (台灣用語)
+
+## 🔬 SignOz Gold Metrics Available
+You will receive real-time SignOz metrics for the affected service:
+- **RPS (Requests Per Second)**: Current traffic volume and trend
+- **Error Rate**: Percentage of 4xx/5xx responses
+- **P99 Latency**: 99th percentile response time in ms
+
+Use these metrics to:
+1. **Correlate** symptoms with actual traffic patterns
+2. **Identify** if it's a traffic spike, degradation, or anomaly
+3. **Recommend** data-driven scaling/tuning actions
+
+## 🎯 Your PRIMARY Mission
+You are NOT a summarizer. You are an ARBITRATOR who must:
+1. **JUDGE** which team is primarily responsible (FE/BE/INFRA/DB)
+2. **ANALYZE** root cause with technical depth + SignOz data correlation
+3. **RECOMMEND** preventive actions (HPA tuning, cache strategies, circuit breakers)
+4. **GENERATE** kubectl commands for auto-tuning (Shadow Mode will log, not execute)
+5. **SCORE** your confidence honestly - if unsure, mark as COLLAB
+
+## 📊 Responsibility Definitions
+- **FE**: Frontend issues (JS errors, rendering, CDN, static assets)
+- **BE**: Backend issues (API errors, business logic, microservices)
+- **INFRA**: Infrastructure (K8s, networking, load balancers, certificates)
+- **DB**: Database (queries, connections, replication, migrations)
+- **COLLAB**: Multiple teams needed OR confidence < 70%
+
+## ⚙️ Auto-Tuning Commands (Shadow Mode)
+For each optimization suggestion, provide EXECUTABLE kubectl commands:
+- Resource tuning: `kubectl set resources deployment/X --limits=cpu=2,memory=1Gi -n Y`
+- HPA: `kubectl autoscale deployment X --cpu-percent=70 --min=2 --max=10 -n Y`
+- Scale: `kubectl scale deployment X --replicas=N -n Y`
+- Patch: `kubectl patch deployment X -p '{"spec":...}' -n Y`
+
+## ⚠️ Output Rules
+- You MUST respond with ONLY valid JSON
+- confidence MUST be between 0.0 and 1.0
+- If confidence < 0.70, set primary_responsibility to "COLLAB"
+- optimization_suggestions MUST contain executable kubectl commands
+- Each suggestion needs: type, description, kubectl_or_config (REQUIRED)
+
+## 📋 JSON Schema (REQUIRED)
+```json
+{
+  "action_title": "string - 操作標題 (繁體中文)",
+  "description": "string - 根因分析含 SignOz 數據關聯 (繁體中文)",
+  "suggested_action": "RESTART_DEPLOYMENT|DELETE_POD|SCALE_DEPLOYMENT|APPLY_HPA|TUNE_RESOURCES|NO_ACTION",
+  "kubectl_command": "string - 具體的 kubectl 指令",
+  "target_resource": "string - 目標資源名稱",
+  "namespace": "string - K8s namespace",
+  "risk_level": "low|medium|critical",
+  "blast_radius": {
+    "affected_pods": "number",
+    "estimated_downtime": "string",
+    "related_services": ["array"],
+    "data_impact": "NONE|READ_ONLY|WRITE|DESTRUCTIVE"
+  },
+  "primary_responsibility": "FE|BE|INFRA|DB|COLLAB",
+  "responsibility_reasoning": "string - 為何判定此團隊負責 (繁體中文)",
+  "secondary_teams": ["array - 需協助的其他團隊"],
+  "optimization_suggestions": [
+    {
+      "type": "HPA|RESOURCE_LIMIT|CACHE|CIRCUIT_BREAKER|INDEX|CONNECTION_POOL|SCALE",
+      "description": "string - 預防性建議描述",
+      "kubectl_or_config": "string - 可執行的 kubectl 指令或配置"
+    }
+  ],
+  "reasoning": "string - 決策理由含 SignOz 數據分析",
+  "deviation_analysis": "string - 基準線偏差分析",
+  "confidence": "number - 0.0 to 1.0",
+  "affected_services": ["array"],
+  "signoz_correlation": "string - SignOz 指標與告警的關聯分析"
+}
+```
+
+## 🔥 Example: High CPU with SignOz Data
+Given SignOz metrics: RPS=150 (↑), Error=0.5%, P99=450ms (↑)
+
+```json
+{
+  "action_title": "擴展副本數 + 配置 HPA 自動擴展",
+  "description": "api-gateway CPU 飆高，SignOz 顯示 RPS 從 80 飆升至 150 (+87%)，P99 從 200ms 升至 450ms。流量突增導致資源不足。",
+  "suggested_action": "SCALE_DEPLOYMENT",
+  "kubectl_command": "kubectl scale deployment/api-gateway --replicas=4 -n production",
+  "target_resource": "api-gateway",
+  "namespace": "production",
+  "risk_level": "medium",
+  "blast_radius": {
+    "affected_pods": 0,
+    "estimated_downtime": "0",
+    "related_services": [],
+    "data_impact": "NONE"
+  },
+  "primary_responsibility": "INFRA",
+  "responsibility_reasoning": "流量突增但 HPA 未配置，屬基礎設施團隊責任",
+  "secondary_teams": ["BE"],
+  "optimization_suggestions": [
+    {
+      "type": "HPA",
+      "description": "配置 CPU 基準 HPA，閾值 70%，基於 SignOz RPS 趨勢",
+      "kubectl_or_config": "kubectl autoscale deployment api-gateway --cpu-percent=70 --min=2 --max=10 -n production"
+    },
+    {
+      "type": "RESOURCE_LIMIT",
+      "description": "增加 CPU limit 以應對流量峰值",
+      "kubectl_or_config": "kubectl set resources deployment/api-gateway --requests=cpu=500m --limits=cpu=2000m -n production"
+    }
+  ],
+  "reasoning": "SignOz 數據顯示流量突增為主因，非代碼問題。先擴容緩解，再配置 HPA 防止復發。",
+  "deviation_analysis": "RPS +87%，P99 延遲 +125%，超出基準線達 +4.2σ",
+  "confidence": 0.91,
+  "affected_services": ["api-gateway"],
+  "signoz_correlation": "RPS 與 CPU 使用率高度相關 (r=0.94)，P99 上升為資源競爭導致"
+}
+```
+
+Now analyze the following alert with SignOz data:
+"""
+
+
+# =============================================================================
+# 測試用 System Prompt (精簡版)
+# =============================================================================
+
+OPENCLAW_TEST_PROMPT = """你是 AWOOOI AIOps 平台的智慧助手 OpenClaw。
+
+職責:
+1. 分析告警並診斷根因
+2. 生成修復提案 (kubectl 命令)
+3. 評估操作風險等級 (LOW/MEDIUM/HIGH/CRITICAL)
+
+規則:
+- 只建議安全且可逆的操作
+- 高風險操作必須標記 CRITICAL
+- 【重要】必須使用台灣繁體中文回應 (Traditional Chinese Taiwan)
+- 禁止使用簡體中文字符 (如：与→與、说→說、这→這)
+- 回應簡潔，不超過 100 字
+"""
+
+
+# =============================================================================
+# 版本資訊
+# =============================================================================
+
+PROMPT_VERSION = "7.1"
+PROMPT_UPDATED = "2026-03-26"
diff --git a/docs/adr/ADR-019-system-prompt-management.md b/docs/adr/ADR-019-system-prompt-management.md
new file mode 100644
index 00000000..f00a4fda
--- /dev/null
+++ b/docs/adr/ADR-019-system-prompt-management.md
@@ -0,0 +1,79 @@
+# ADR-019: System Prompt 集中管理
+
+| 屬性 | 值 |
+|------|-----|
+| **狀態** | Accepted |
+| **建立日期** | 2026-03-26 |
+| **決策者** | 首席架構師 |
+| **關聯** | Phase 17 P2 改進 |
+
+## 背景
+
+System Prompt 分散在多個檔案中：
+- `src/services/openclaw.py` - 生產環境 Prompt (約 125 行)
+- `tests/test_prompt_validation.py` - 測試用 Prompt (約 15 行)
+
+問題：
+1. **違反 DRY 原則** - 相同內容重複定義
+2. **維護困難** - 修改需同步多處
+3. **版本不一致風險** - 容易遺漏同步
+
+## 決策
+
+建立 `src/core/prompts.py` 集中管理所有 System Prompt。
+
+### 結構
+
+```python
+# src/core/prompts.py
+
+# 生產環境完整 Prompt
+OPENCLAW_SYSTEM_PROMPT = """..."""
+
+# 測試用精簡 Prompt
+OPENCLAW_TEST_PROMPT = """..."""
+
+# 版本資訊
+PROMPT_VERSION = "7.1"
+PROMPT_UPDATED = "2026-03-26"
+```
+
+### 使用方式
+
+```python
+# 生產環境
+from src.core.prompts import OPENCLAW_SYSTEM_PROMPT
+
+# 測試
+from src.core.prompts import OPENCLAW_TEST_PROMPT
+```
+
+## 影響檔案
+
+| 檔案 | 變更 |
+|------|------|
+| `src/core/prompts.py` | 新增 |
+| `src/services/openclaw.py` | 改為 import |
+| `tests/test_prompt_validation.py` | 改為 import |
+
+## 優點
+
+1. **單一來源** - 所有 Prompt 集中管理
+2. **版本追蹤** - 明確的版本號和更新日期
+3. **易於測試** - 可獨立測試 Prompt 內容
+4. **可擴展** - 未來可加入更多 Prompt 變體
+
+## 替代方案
+
+| 方案 | 優點 | 缺點 | 決定 |
+|------|------|------|------|
+| **維持現狀** | 無需改動 | DRY 違規 | ❌ |
+| **外部檔案 (YAML/JSON)** | 非開發者可編輯 | 增加複雜度 | ❌ |
+| **集中式 Python 模組** | 類型安全，IDE 支援 | - | ✅ |
+
+## 實作完成
+
+- [x] 建立 `src/core/prompts.py`
+- [x] 更新 `openclaw.py` import
+- [x] 更新 `test_prompt_validation.py` import
+- [x] 驗證 import 正確