diff --git a/docs/guides/observability_ui_governance.md b/docs/guides/observability_ui_governance.md
index db63c54..a82e010 100644
--- a/docs/guides/observability_ui_governance.md
+++ b/docs/guides/observability_ui_governance.md
@@ -64,6 +64,7 @@ python3 scripts/sync_observability_css.py
 
 Guard 會檢查：
 
+- 觀測台頁面契約集中在 `scripts/observability_contract.py`，新增/改名頁面先改這裡。
 - Times / Georgia 等非規範標題字型。
 - SQL/Jinja exception 文案外露。
 - 圖表 `style="height:..."` 與靜態 `style="width:..."`。
diff --git a/scripts/check_observability_pages.py b/scripts/check_observability_pages.py
index 50d9b93..b8f1161 100644
--- a/scripts/check_observability_pages.py
+++ b/scripts/check_observability_pages.py
@@ -13,32 +13,7 @@ import sys
 import urllib.error
 import urllib.request
 
-
-PAGES = [
-    ("/observability/overview", "總覽"),
-    ("/observability/agent_orchestration", "Agent"),
-    ("/observability/business_intel", "商業"),
-    ("/observability/host_health", "主機"),
-    ("/observability/ai_calls", "AI 呼叫"),
-    ("/observability/budget", "預算"),
-    ("/observability/promotion_review", "晉升"),
-    ("/observability/rag_queries", "RAG"),
-    ("/observability/quality_trend", "品質"),
-    ("/observability/ppt_audit_history", "PPT"),
-]
-
-EXPECTED_MARKERS = {
-    "/observability/overview": ["觀測台總覽", "主機健康", "AI 呼叫"],
-    "/observability/agent_orchestration": ["Agent 編排矩陣", "LLM", "MCP", "RAG"],
-    "/observability/business_intel": ["商業面 × AI", "AI", "競品"],
-    "/observability/host_health": ["主機健康", "Ollama", "AutoHeal"],
-    "/observability/ai_calls": ["AI 呼叫", "Provider", "RAG"],
-    "/observability/budget": ["預算控管", "force", "throttle"],
-    "/observability/promotion_review": ["RAG 晉升審核", "Promotion", "ai_insights"],
-    "/observability/rag_queries": ["RAG 召回詳情", "最近 50", "hits"],
-    "/observability/quality_trend": ["反饋趨勢", "Caller", "蒸餾"],
-    "/observability/ppt_audit_history": ["PPT 視覺審核", "AiderHeal", "audit"],
-}
+from observability_contract import CSS_ASSET_CHECKS, OBSERVABILITY_PAGES
 
 MIN_HTML_BYTES = 2500
 
@@ -49,20 +24,6 @@ GLOBAL_REQUIRED_MARKERS = [
     "momo-obs-link",
 ]
 
-ASSET_CHECKS = [
-    (
-        "/static/css/observability-system.css",
-        "觀測台 CSS",
-        [
-            "--obs-title-size",
-            "--obs-value-size",
-            ".momo-observability-mode",
-            ".obs-chart-frame",
-            ".obs-modal-preview",
-        ],
-    ),
-]
-
 ERROR_NEEDLES = [
     "Traceback",
     "UndefinedError",
@@ -93,21 +54,21 @@ def main() -> int:
     failed = False
     print(f"Observability page smoke: {args.base_url.rstrip('/')}")
 
-    for path, label in PAGES:
+    for page in OBSERVABILITY_PAGES:
         try:
-            status, html = fetch_page(args.base_url, path, args.timeout)
+            status, html = fetch_page(args.base_url, page.url, args.timeout)
         except urllib.error.HTTPError as exc:
-            print(f"- {label}: HTTP {exc.code}, FAIL")
+            print(f"- {page.short_label}: HTTP {exc.code}, FAIL")
             failed = True
             continue
         except Exception as exc:
-            print(f"- {label}: {type(exc).__name__}: {exc}, FAIL")
+            print(f"- {page.short_label}: {type(exc).__name__}: {exc}, FAIL")
             failed = True
             continue
 
         found = [needle for needle in ERROR_NEEDLES if needle in html]
         missing_markers = [
-            marker for marker in EXPECTED_MARKERS.get(path, [])
+            marker for marker in page.markers
             if marker not in html
         ]
         missing_global_markers = [
@@ -127,34 +88,34 @@ def main() -> int:
                 issues.append(f"missing_global_markers={missing_global_markers}")
             if too_small:
                 issues.append(f"html_too_small={len(html.encode('utf-8'))}B")
-            print(f"- {label}: HTTP {status}, issues={issues}, FAIL")
+            print(f"- {page.short_label}: HTTP {status}, issues={issues}, FAIL")
             failed = True
         else:
-            print(f"- {label}: HTTP {status}, issues=none")
+            print(f"- {page.short_label}: HTTP {status}, issues=none")
 
-    for path, label, markers in ASSET_CHECKS:
+    for asset in CSS_ASSET_CHECKS:
         try:
-            status, body = fetch_page(args.base_url, path, args.timeout)
+            status, body = fetch_page(args.base_url, asset.url, args.timeout)
         except urllib.error.HTTPError as exc:
-            print(f"- {label}: HTTP {exc.code}, FAIL")
+            print(f"- {asset.label}: HTTP {exc.code}, FAIL")
             failed = True
             continue
         except Exception as exc:
-            print(f"- {label}: {type(exc).__name__}: {exc}, FAIL")
+            print(f"- {asset.label}: {type(exc).__name__}: {exc}, FAIL")
             failed = True
             continue
 
-        missing_markers = [marker for marker in markers if marker not in body]
+        missing_markers = [marker for marker in asset.markers if marker not in body]
         if status != 200 or missing_markers:
             issues = []
             if status != 200:
                 issues.append("bad_status")
             if missing_markers:
                 issues.append(f"missing_asset_markers={missing_markers}")
-            print(f"- {label}: HTTP {status}, issues={issues}, FAIL")
+            print(f"- {asset.label}: HTTP {status}, issues={issues}, FAIL")
             failed = True
         else:
-            print(f"- {label}: HTTP {status}, markers=ok")
+            print(f"- {asset.label}: HTTP {status}, markers=ok")
 
     if failed:
         print("Observability page smoke: FAIL")
diff --git a/scripts/check_observability_ui.py b/scripts/check_observability_ui.py
index 8736342..18149bb 100644
--- a/scripts/check_observability_ui.py
+++ b/scripts/check_observability_ui.py
@@ -14,34 +14,11 @@ import sys
 from dataclasses import dataclass
 from pathlib import Path
 
+from observability_contract import OBSERVABILITY_PAGES
 
 ROOT = Path(__file__).resolve().parents[1]
 
-TEMPLATE_PATHS = [
-    "templates/admin/observability_overview.html",
-    "templates/admin/agent_orchestration.html",
-    "templates/admin/business_intel.html",
-    "templates/admin/host_health.html",
-    "templates/admin/ai_calls_dashboard.html",
-    "templates/admin/budget.html",
-    "templates/admin/promotion_review.html",
-    "templates/admin/rag_queries.html",
-    "templates/admin/quality_trend.html",
-    "templates/admin/ppt_audit_history.html",
-]
-
-OBSERVABILITY_NAV_ITEMS = [
-    ("templates/admin/observability_overview.html", "obs_overview", "/observability/overview", "觀測台總覽"),
-    ("templates/admin/agent_orchestration.html", "obs_agent_orchestration", "/observability/agent_orchestration", "Agent 編排矩陣"),
-    ("templates/admin/business_intel.html", "obs_business_intel", "/observability/business_intel", "商業面 × AI"),
-    ("templates/admin/host_health.html", "obs_host_health", "/observability/host_health", "主機健康"),
-    ("templates/admin/ai_calls_dashboard.html", "obs_ai_calls", "/observability/ai_calls", "AI 呼叫"),
-    ("templates/admin/budget.html", "obs_budget", "/observability/budget", "預算控管"),
-    ("templates/admin/promotion_review.html", "obs_promotion_review", "/observability/promotion_review", "RAG 晉升審核"),
-    ("templates/admin/rag_queries.html", "obs_rag_queries", "/observability/rag_queries", "RAG 召回詳情"),
-    ("templates/admin/quality_trend.html", "obs_quality_trend", "/observability/quality_trend", "反饋趨勢"),
-    ("templates/admin/ppt_audit_history.html", "obs_ppt_audit", "/observability/ppt_audit_history", "PPT 視覺審核"),
-]
+TEMPLATE_PATHS = [page.template for page in OBSERVABILITY_PAGES]
 
 CSS_PATH = Path("static/css/observability-system.css")
 WEB_CSS_PATH = Path("web/static/css/observability-system.css")
@@ -267,42 +244,44 @@ def scan_nav_contract() -> list[str]:
     route_text = route_path.read_text(encoding="utf-8") if route_path.exists() else ""
     findings: list[str] = []
 
-    for template_path, active_page, url, label in OBSERVABILITY_NAV_ITEMS:
-        template = ROOT / template_path
+    for page in OBSERVABILITY_PAGES:
+        template = ROOT / page.template
         if not template.exists():
-            findings.append(f"{template_path}: missing observability template for `{label}`")
+            findings.append(f"{page.template}: missing observability template for `{page.label}`")
             continue
 
         template_text = template.read_text(encoding="utf-8")
         active_pattern = re.compile(
-            r"set\s+active_page\s*=\s*['\"]" + re.escape(active_page) + r"['\"]"
+            r"set\s+active_page\s*=\s*['\"]" + re.escape(page.active_page) + r"['\"]"
+        )
+        route_has_contract = (
+            page.template.replace("templates/", "") in route_text
+            and page.active_page in route_text
         )
-        route_has_contract = template_path.replace("templates/", "") in route_text and active_page in route_text
         if not active_pattern.search(template_text) and not route_has_contract:
             findings.append(
-                f"{template_path}: active_page must be `{active_page}` in template or route for `{label}`"
+                f"{page.template}: active_page must be `{page.active_page}` in template or route for `{page.label}`"
             )
 
-        if active_page not in shell_text:
-            findings.append(f"{SHELL_PATH}: sidebar missing active_page `{active_page}`")
-        if url not in shell_text:
-            findings.append(f"{SHELL_PATH}: sidebar missing URL `{url}` for `{label}`")
-        if label not in shell_text:
-            findings.append(f"{SHELL_PATH}: sidebar missing label `{label}`")
-        if active_page not in base_text:
-            findings.append(f"{BASE_PATH}: momo-observability-mode list missing `{active_page}`")
+        if page.active_page not in shell_text:
+            findings.append(f"{SHELL_PATH}: sidebar missing active_page `{page.active_page}`")
+        if page.url not in shell_text:
+            findings.append(f"{SHELL_PATH}: sidebar missing URL `{page.url}` for `{page.label}`")
+        if page.label not in shell_text:
+            findings.append(f"{SHELL_PATH}: sidebar missing label `{page.label}`")
+        if page.active_page not in base_text:
+            findings.append(f"{BASE_PATH}: momo-observability-mode list missing `{page.active_page}`")
 
-        route_suffix = url.replace("/observability", "", 1) or "/"
         route_pattern = re.compile(
             r"@admin_observability_bp\.route\(\s*['\"]"
-            + re.escape(route_suffix)
+            + re.escape(page.route_suffix)
             + r"['\"]"
         )
         if route_text and not route_pattern.search(route_text):
-            findings.append(f"{ROUTE_PATH}: missing route `{route_suffix}` for `{label}`")
+            findings.append(f"{ROUTE_PATH}: missing route `{page.route_suffix}` for `{page.label}`")
 
     sidebar_observability_links = set(re.findall(r'href="(/observability/[^"]+)"', shell_text))
-    expected_links = {url for _, _, url, _ in OBSERVABILITY_NAV_ITEMS}
+    expected_links = {page.url for page in OBSERVABILITY_PAGES}
     extra_links = sorted(sidebar_observability_links - expected_links)
     missing_links = sorted(expected_links - sidebar_observability_links)
     for url in extra_links:
@@ -333,7 +312,7 @@ def main() -> int:
     print(f"- css guardrails checked: {len(REQUIRED_CSS_SNIPPETS)}")
     print(f"- sidebar/nav guardrails checked: {len(REQUIRED_SHELL_SNIPPETS)}")
     print(f"- base/topbar guardrails checked: {len(REQUIRED_BASE_SNIPPETS) + len(FORBIDDEN_BASE_PATTERNS)}")
-    print(f"- nav contract checked: {len(OBSERVABILITY_NAV_ITEMS)} pages")
+    print(f"- nav contract checked: {len(OBSERVABILITY_PAGES)} pages")
     return 0
 
 
diff --git a/scripts/observability_contract.py b/scripts/observability_contract.py
new file mode 100644
index 0000000..9099f90
--- /dev/null
+++ b/scripts/observability_contract.py
@@ -0,0 +1,125 @@
+"""Single source of truth for AI observability QA contracts."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class ObservabilityPage:
+    template: str
+    active_page: str
+    url: str
+    label: str
+    short_label: str
+    markers: tuple[str, ...]
+
+    @property
+    def route_suffix(self) -> str:
+        return self.url.replace("/observability", "", 1) or "/"
+
+
+@dataclass(frozen=True)
+class AssetCheck:
+    url: str
+    label: str
+    markers: tuple[str, ...]
+
+
+OBSERVABILITY_PAGES = (
+    ObservabilityPage(
+        "templates/admin/observability_overview.html",
+        "obs_overview",
+        "/observability/overview",
+        "觀測台總覽",
+        "總覽",
+        ("觀測台總覽", "主機健康", "AI 呼叫"),
+    ),
+    ObservabilityPage(
+        "templates/admin/agent_orchestration.html",
+        "obs_agent_orchestration",
+        "/observability/agent_orchestration",
+        "Agent 編排矩陣",
+        "Agent",
+        ("Agent 編排矩陣", "LLM", "MCP", "RAG"),
+    ),
+    ObservabilityPage(
+        "templates/admin/business_intel.html",
+        "obs_business_intel",
+        "/observability/business_intel",
+        "商業面 × AI",
+        "商業",
+        ("商業面 × AI", "AI", "競品"),
+    ),
+    ObservabilityPage(
+        "templates/admin/host_health.html",
+        "obs_host_health",
+        "/observability/host_health",
+        "主機健康",
+        "主機",
+        ("主機健康", "Ollama", "AutoHeal"),
+    ),
+    ObservabilityPage(
+        "templates/admin/ai_calls_dashboard.html",
+        "obs_ai_calls",
+        "/observability/ai_calls",
+        "AI 呼叫",
+        "AI 呼叫",
+        ("AI 呼叫", "Provider", "RAG"),
+    ),
+    ObservabilityPage(
+        "templates/admin/budget.html",
+        "obs_budget",
+        "/observability/budget",
+        "預算控管",
+        "預算",
+        ("預算控管", "force", "throttle"),
+    ),
+    ObservabilityPage(
+        "templates/admin/promotion_review.html",
+        "obs_promotion_review",
+        "/observability/promotion_review",
+        "RAG 晉升審核",
+        "晉升",
+        ("RAG 晉升審核", "Promotion", "ai_insights"),
+    ),
+    ObservabilityPage(
+        "templates/admin/rag_queries.html",
+        "obs_rag_queries",
+        "/observability/rag_queries",
+        "RAG 召回詳情",
+        "RAG",
+        ("RAG 召回詳情", "最近 50", "hits"),
+    ),
+    ObservabilityPage(
+        "templates/admin/quality_trend.html",
+        "obs_quality_trend",
+        "/observability/quality_trend",
+        "反饋趨勢",
+        "品質",
+        ("反饋趨勢", "Caller", "蒸餾"),
+    ),
+    ObservabilityPage(
+        "templates/admin/ppt_audit_history.html",
+        "obs_ppt_audit",
+        "/observability/ppt_audit_history",
+        "PPT 視覺審核",
+        "PPT",
+        ("PPT 視覺審核", "AiderHeal", "audit"),
+    ),
+)
+
+
+CSS_ASSET_CHECKS = (
+    AssetCheck(
+        "/static/css/observability-system.css",
+        "觀測台 CSS",
+        (
+            "--obs-title-size",
+            "--obs-value-size",
+            ".momo-observability-mode",
+            ".obs-chart-frame",
+            ".obs-modal-preview",
+        ),
+    ),
+)