diff --git a/TODO_NEXT_STEPS.txt b/TODO_NEXT_STEPS.txt
index 4415009..3e34ba7 100644
--- a/TODO_NEXT_STEPS.txt
+++ b/TODO_NEXT_STEPS.txt
@@ -4,6 +4,7 @@
 ================================================================================
 
 【已完成】
+   - V10.515 補 Webcrumbs host data 硬性授權：即使正式環境 `DISABLE_LOGIN=true` 讓一般 `@login_required` 放行，`/api/webcrumbs/marketplace-host-data` 仍必須有登入 session 或 `X-Internal-Key` 才能取真實 SKU/價差；`/webcrumbs` 未授權時只注入 `auth_required` 空狀態，避免 inline seed data 公開正式比價資料。
    - V10.514 新增 Webcrumbs MOMO/PChome host data read-only API：`/api/webcrumbs/marketplace-host-data` 回傳與 `/webcrumbs` inline seed 相同的登入後 JSON contract，提供 plugin / QA / 其他專案 proxy 驗證；API boundary 明確標示不寫 DB、不呼叫 LLM、不抓外站，只允許 exact / total_price / price_alert_exact 價差摘要。
    - V10.513 外部工具診斷頁 payload 模組化：新增 `services/external_tool_payload_service.py`，把 Metabase/Grist/Webcrumbs 的診斷 payload 與 Webcrumbs host data 組裝移出 `routes/system_public_routes.py`，讓 route 回到 HTTP glue，`system_public_routes.py` 從 600+ 行降至 500 行內。
    - V10.512 Webcrumbs live plugin 接上 MOMO/PChome 只讀 host data：新增 `services/webcrumbs_host_data_service.py`，復用 `competitor_intel_repository.fetch_top_competitor_risks()` / coverage，把 exact / total_price / price_alert_exact 價差摘要轉成 `StockPlatformSharedUI.marketSnapshot` / `aiCandidate`；不呼叫 LLM、不抓外站、不寫 DB，無風險或失敗時仍輸出安全空狀態。
diff --git a/config.py b/config.py
index b80f5be..11ceed8 100644
--- a/config.py
+++ b/config.py
@@ -402,7 +402,7 @@ YOUTUBE_API_KEY = os.getenv('YOUTUBE_API_KEY', '')
 # ==========================================
 # 系統版本與路徑
 # ==========================================
-SYSTEM_VERSION = "V10.514"
+SYSTEM_VERSION = "V10.515"
 LOG_FILE_PATH = os.path.join(BASE_DIR, 'logs/system.log')
 public_url = PUBLIC_URL  # 用於模板顯示
 
diff --git a/docs/guides/webcrumbs_shared_runtime.md b/docs/guides/webcrumbs_shared_runtime.md
index 91d0ee0..3db373a 100644
--- a/docs/guides/webcrumbs_shared_runtime.md
+++ b/docs/guides/webcrumbs_shared_runtime.md
@@ -64,7 +64,8 @@ style.css
 
 - `/webcrumbs` 顯示 runtime URL、版本與 plugin base。
 - `/webcrumbs` 會嵌入同源 `/webcrumbs-assets/plugins/...` 的 live plugin preview，並由 momo-pro 注入只讀 MOMO/PChome exact 價差摘要；若資料源不可用或無風險候選，改注入診斷空狀態，避免 plugin fallback demo 數字在正式頁面被誤認成真實市場或 AI 建議。
-- `/api/webcrumbs/marketplace-host-data` 會回傳同一份登入後只讀 host data contract，供 plugin / QA / 其他專案 proxy 驗證；boundary 必須標示 `writes_database=false`、`calls_llm=false`、`fetches_external=false`。
+- `/api/webcrumbs/marketplace-host-data` 會回傳同一份登入後只讀 host data contract，供 plugin / QA / 其他專案 proxy 驗證；即使全站 `DISABLE_LOGIN=true`，此 API 仍必須要求登入 session 或 `X-Internal-Key`，boundary 必須標示 `writes_database=false`、`calls_llm=false`、`fetches_external=false`。
+- `/webcrumbs` 未取得登入 session 或 `X-Internal-Key` 時只能注入 `auth_required` 空狀態，不得把真實 SKU、價格或價差寫進 inline seed data。
 - `/webcrumbs-assets/loader/webcrumbs-compatible-loader.js` 回 200 且 content type 是 JavaScript。
 - `ewoooc_base.html` 在 `WEBCRUMBS_ENABLED=true` 且 runtime URL 有效時輸出 `<script data-webcrumbs-runtime=...>`。
 - 任一試點頁嵌入 plugin 後，瀏覽器 console 不應有 `MISSING_URI`、`STYLE_LOAD_ERROR`、`SCRIPT_LOAD_ERROR`。
diff --git a/docs/memory/history_logs.md b/docs/memory/history_logs.md
index 705e1aa..637654c 100644
--- a/docs/memory/history_logs.md
+++ b/docs/memory/history_logs.md
@@ -13,6 +13,7 @@
 ## 📅 詳細更新日誌 (考古存檔)
 
 ### 2026-05-31：Webcrumbs 共用 UI Runtime 與市場情報 writer approval
+- **V10.515 Webcrumbs host data 硬性授權**: 發現正式環境一般 `@login_required` 可能因 `DISABLE_LOGIN=true` 放行後，為 `/api/webcrumbs/marketplace-host-data` 與 `/webcrumbs` inline seed 加上獨立授權判斷；只有登入 session 或 `X-Internal-Key` 可取得真實 SKU/價差，未授權時只回 `auth_required` 空狀態，避免 public runtime 診斷頁洩漏正式比價資料。
 - **V10.514 Webcrumbs host data read-only API**: 新增登入後 `/api/webcrumbs/marketplace-host-data`，回傳與 `/webcrumbs` inline seed 相同的 MOMO/PChome exact 價差 host data contract，供 plugin、QA 與其他專案 proxy 驗證；API boundary 明確標示 `writes_database=false`、`calls_llm=false`、`fetches_external=false`，且只允許 exact / total_price / price_alert_exact 摘要。
 - **V10.513 外部工具診斷 payload 模組化**: 新增 `services/external_tool_payload_service.py`，把 Metabase/Grist/Webcrumbs 診斷頁 payload 與 Webcrumbs host data 組裝從 `routes/system_public_routes.py` 移出；route 保持 HTTP glue 與 asset proxy，避免 Webcrumbs live plugin 與比價 host data 持續把公開系統 route 撐成大檔。
 - **V10.512 Webcrumbs MOMO/PChome host data**: 新增 `services/webcrumbs_host_data_service.py`，讓 `/webcrumbs` live plugin preview 復用 `competitor_intel_repository.fetch_top_competitor_risks()` 與 coverage，將 exact / total_price / price_alert_exact 的只讀價差摘要轉成 `StockPlatformSharedUI.marketSnapshot` / `aiCandidate`；不呼叫 LLM、不抓外站、不寫 DB，無風險或讀取失敗時仍輸出安全空狀態。
diff --git a/routes/system_public_routes.py b/routes/system_public_routes.py
index be7348b..14ff50830 100644
--- a/routes/system_public_routes.py
+++ b/routes/system_public_routes.py
@@ -6,13 +6,14 @@
 """
 
 import os
+import hmac
 import mimetypes
 import posixpath
 import zipfile
 from datetime import datetime, timezone, timedelta
 from urllib.parse import quote
 
-from flask import Blueprint, Response, jsonify, render_template, request, send_from_directory, url_for
+from flask import Blueprint, Response, jsonify, render_template, request, send_from_directory, session, url_for
 import requests
 from sqlalchemy import text
 
@@ -26,7 +27,10 @@ from config import (
 )
 from database.manager import DatabaseManager
 from database.models import Product, PriceRecord
-from services.external_tool_payload_service import build_external_tool_payload, build_webcrumbs_seed_data
+from services.external_tool_payload_service import (
+    build_external_tool_payload,
+    build_webcrumbs_seed_data,
+)
 from services.json_storage import load_categories
 from services.logger_manager import SystemLogger
 from utils.security import safe_join
@@ -42,6 +46,14 @@ STATIC_DIR = os.path.join(BASE_DIR, 'web/static')
 WEBCRUMBS_ASSET_ALLOWED_PREFIXES = ('loader/', 'plugins/', 'demo/')
 
 
+def _has_sensitive_webcrumbs_access():
+    if session.get('logged_in'):
+        return True
+    internal_key = os.getenv('INTERNAL_API_KEY', '').strip()
+    provided = request.headers.get('X-Internal-Key', '').strip()
+    return bool(internal_key and provided and hmac.compare_digest(provided, internal_key))
+
+
 @system_public_bp.route('/favicon.ico')
 def favicon():
     """使用既有品牌圖示回應瀏覽器預設 favicon 探測，避免全站 404 噪音。"""
@@ -104,7 +116,10 @@ def webcrumbs_status():
         'external_tool_status.html',
         active_page='webcrumbs',
         system_version=SYSTEM_VERSION,
-        tool=build_external_tool_payload('webcrumbs'),
+        tool=build_external_tool_payload(
+            'webcrumbs',
+            include_host_data=_has_sensitive_webcrumbs_access(),
+        ),
     )
 
 
@@ -112,6 +127,19 @@ def webcrumbs_status():
 @login_required
 def webcrumbs_marketplace_host_data_api():
     """Read-only host data contract for Webcrumbs shared-ui plugins."""
+    if not _has_sensitive_webcrumbs_access():
+        return jsonify({
+            'success': False,
+            'error': 'auth_required',
+            'message': 'MOMO/PChome host data requires a logged-in session or X-Internal-Key.',
+            'boundary': {
+                'auth_required': True,
+                'writes_database': False,
+                'calls_llm': False,
+                'fetches_external': False,
+            },
+        }), 401
+
     limit = request.args.get('limit', 5, type=int) or 5
     limit = max(1, min(limit, 8))
     payload = build_webcrumbs_seed_data(limit=limit)
diff --git a/services/external_tool_payload_service.py b/services/external_tool_payload_service.py
index 3aab9eb..f191f21 100644
--- a/services/external_tool_payload_service.py
+++ b/services/external_tool_payload_service.py
@@ -62,6 +62,37 @@ def _is_blocked_external_url(configured_url):
     return parsed.scheme in {"http", "https"} and parsed.hostname != "mo.wooo.work"
 
 
+def build_webcrumbs_auth_required_seed_data():
+    """Return a non-sensitive host data shape when auth is not proven."""
+    return {
+        "marketSnapshot": [
+            {
+                "name": "MOMO/PChome host data requires authentication",
+                "price": "not_available",
+                "change_pct": "not_available",
+                "freshness_status": "auth_required",
+            }
+        ],
+        "aiCandidate": {
+            "ticker": "-",
+            "name": "MOMO/PChome host data locked",
+            "thesis": "Webcrumbs runtime 已接入，但真實 SKU、價格與候選摘要需要登入 session 或 X-Internal-Key；未授權時不顯示 fallback demo 數字，也不顯示正式比價資料。",
+            "confidence_score": "not_available",
+            "risk_level": "auth_required",
+            "release_status": "blocked",
+            "evidence_refs": ["auth_required"],
+            "updated_at": SYSTEM_VERSION,
+        },
+        "metadata": {
+            "source": "auth_required",
+            "row_count": 0,
+            "writes_database": False,
+            "calls_llm": False,
+            "fetches_external": False,
+        },
+    }
+
+
 def build_webcrumbs_seed_data(limit: int = 5):
     """Build safe Webcrumbs host data for page seed and read-only API."""
     try:
@@ -115,7 +146,7 @@ def _metabase_payload():
     }
 
 
-def _webcrumbs_payload():
+def _webcrumbs_payload(include_host_data: bool = True):
     runtime_ready = bool(WEBCRUMBS_ENABLED and WEBCRUMBS_RUNTIME_URL)
     launch_url = WEBCRUMBS_BASE_URL if WEBCRUMBS_BASE_URL else ""
     plugin_base = (WEBCRUMBS_PLUGIN_BASE_URL or "").rstrip("/")
@@ -171,7 +202,11 @@ def _webcrumbs_payload():
         ],
         "plugin_previews": plugin_previews,
         "plugin_preview_uris": [preview["uri"] for preview in plugin_previews],
-        "plugin_seed_data": build_webcrumbs_seed_data(limit=5),
+        "plugin_seed_data": (
+            build_webcrumbs_seed_data(limit=5)
+            if include_host_data
+            else build_webcrumbs_auth_required_seed_data()
+        ),
     }
 
 
@@ -201,10 +236,10 @@ def _grist_payload():
     }
 
 
-def build_external_tool_payload(kind):
+def build_external_tool_payload(kind, include_host_data: bool = True):
     """建立外部工具診斷頁 payload。"""
     if kind == "metabase":
         return _metabase_payload()
     if kind == "webcrumbs":
-        return _webcrumbs_payload()
+        return _webcrumbs_payload(include_host_data=include_host_data)
     return _grist_payload()
diff --git a/tests/test_external_tool_entrypoints.py b/tests/test_external_tool_entrypoints.py
index a2a78fb..c0c8c03 100644
--- a/tests/test_external_tool_entrypoints.py
+++ b/tests/test_external_tool_entrypoints.py
@@ -32,7 +32,13 @@ def test_external_tool_bridge_pages_are_diagnostic_not_blank():
     css = (ROOT / "web/static/css/page-external-tools.css").read_text(encoding="utf-8")
 
     assert "build_external_tool_payload" in route_source
-    assert "def build_external_tool_payload(kind)" in service_source
+    assert "def _has_sensitive_webcrumbs_access()" in route_source
+    assert "hmac.compare_digest(provided, internal_key)" in route_source
+    assert "include_host_data=_has_sensitive_webcrumbs_access()" in route_source
+    assert "def build_external_tool_payload(kind, include_host_data: bool = True)" in service_source
+    assert "include_host_data: bool = True" in service_source
+    assert "def build_webcrumbs_auth_required_seed_data()" in service_source
+    assert "auth_required" in service_source
     assert 'parsed.path.rstrip("/") == bridge_path.rstrip("/")' in service_source
     assert "def _is_blocked_external_url(configured_url)" in service_source
     assert "external-tool-checks" in template
@@ -41,6 +47,8 @@ def test_external_tool_bridge_pages_are_diagnostic_not_blank():
     assert "def webcrumbs_status()" in route_source
     assert "@system_public_bp.route('/api/webcrumbs/marketplace-host-data')" in route_source
     assert "def webcrumbs_marketplace_host_data_api()" in route_source
+    assert "if not _has_sensitive_webcrumbs_access()" in route_source
+    assert "'error': 'auth_required'" in route_source
     assert "build_webcrumbs_seed_data(limit=limit)" in route_source
     assert "'allowed_match_contract': 'exact/total_price/price_alert_exact'" in route_source
     assert "def webcrumbs_asset_proxy(asset_path)" in route_source
diff --git a/tests/test_webcrumbs_host_data_service.py b/tests/test_webcrumbs_host_data_service.py
index 9d30abf..ea409bf 100644
--- a/tests/test_webcrumbs_host_data_service.py
+++ b/tests/test_webcrumbs_host_data_service.py
@@ -81,3 +81,15 @@ def test_webcrumbs_seed_data_fallback_does_not_expose_demo_values(monkeypatch):
     assert payload["aiCandidate"]["release_status"] == "blocked"
     assert "fallback demo" in payload["aiCandidate"]["thesis"]
     assert "TAIEX" not in str(payload)
+
+
+def test_webcrumbs_auth_required_seed_data_is_non_sensitive():
+    from services.external_tool_payload_service import build_webcrumbs_auth_required_seed_data
+
+    payload = build_webcrumbs_auth_required_seed_data()
+
+    assert payload["marketSnapshot"][0]["freshness_status"] == "auth_required"
+    assert payload["aiCandidate"]["release_status"] == "blocked"
+    assert payload["metadata"]["source"] == "auth_required"
+    assert "MOMO NT$" not in str(payload)
+    assert "PChome NT$" not in str(payload)