diff --git a/apps/api/src/api/v1/health.py b/apps/api/src/api/v1/health.py
index ce284106..0c24b766 100644
--- a/apps/api/src/api/v1/health.py
+++ b/apps/api/src/api/v1/health.py
@@ -26,6 +26,11 @@ from pydantic import BaseModel
 from src.core.config import settings
 from src.core.logging import get_logger
 from src.services.health_check_service import get_health_check_service
+from src.services.ollama_endpoint_circuit_breaker import (
+    get_ollama_endpoint_cooldown_remaining_seconds,
+    record_ollama_endpoint_failure,
+    record_ollama_endpoint_success,
+)
 from src.services.ollama_endpoint_resolver import resolve_ollama_order
 
 router = APIRouter()
@@ -137,11 +142,7 @@ async def check_ollama_provider_chain() -> tuple[ComponentHealth, dict[str, Comp
 
     checked = await asyncio.gather(
         *(
-            _http_health_check(
-                selection.provider_name,
-                selection.url,
-                "/api/tags",
-            )
+            _ollama_endpoint_health_check(selection.provider_name, selection.url)
             for selection in selections
         )
     )
@@ -187,6 +188,22 @@ async def check_ollama_provider_chain() -> tuple[ComponentHealth, dict[str, Comp
     )
 
 
+async def _ollama_endpoint_health_check(name: str, url: str) -> ComponentHealth:
+    cooldown_remaining = get_ollama_endpoint_cooldown_remaining_seconds(url)
+    if cooldown_remaining > 0:
+        return ComponentHealth(
+            status="down",
+            error=f"recent endpoint failure cooldown: {cooldown_remaining:.0f}s",
+        )
+
+    result = await _http_health_check(name, url, "/api/tags")
+    if result.status == "up":
+        record_ollama_endpoint_success(url)
+    else:
+        record_ollama_endpoint_failure(url)
+    return result
+
+
 async def check_openclaw() -> ComponentHealth:
     """Async OpenClaw health check via /health"""
     return await _http_health_check("openclaw", settings.OPENCLAW_URL, "/health")
diff --git a/apps/api/src/services/ollama_endpoint_circuit_breaker.py b/apps/api/src/services/ollama_endpoint_circuit_breaker.py
index 84271f61..a68cee5f 100644
--- a/apps/api/src/services/ollama_endpoint_circuit_breaker.py
+++ b/apps/api/src/services/ollama_endpoint_circuit_breaker.py
@@ -1,9 +1,9 @@
 """
 Lightweight in-process cooldown for noisy Ollama endpoint failures.
 
-This does not change ADR-110 policy order. It only suppresses endpoints that
-just failed for short-lived high-volume callers such as embedding/RAG, while
-leaving health checks and failover status free to probe the full topology.
+This does not change ADR-110 policy order. It suppresses endpoints that just
+failed for short-lived callers while still returning explicit offline/cooldown
+state to health and route-status surfaces.
 """
 
 from __future__ import annotations
@@ -60,6 +60,26 @@ def is_ollama_endpoint_blocked(url: str, *, now: float | None = None) -> bool:
     return True
 
 
+def get_ollama_endpoint_cooldown_remaining_seconds(
+    url: str,
+    *,
+    now: float | None = None,
+) -> float:
+    """Return remaining cooldown seconds for display/debug surfaces."""
+    if not url:
+        return 0.0
+    current_time = time.monotonic() if now is None else now
+    normalized = _normalize_url(url)
+    blocked_until = _blocked_until_by_url.get(normalized)
+    if blocked_until is None:
+        return 0.0
+    remaining = blocked_until - current_time
+    if remaining <= 0:
+        _blocked_until_by_url.pop(normalized, None)
+        return 0.0
+    return remaining
+
+
 def filter_ollama_urls_with_cooldown(
     urls: Iterable[str],
     *,
diff --git a/apps/api/src/services/ollama_health_monitor.py b/apps/api/src/services/ollama_health_monitor.py
index e7e3e182..f353e8a4 100644
--- a/apps/api/src/services/ollama_health_monitor.py
+++ b/apps/api/src/services/ollama_health_monitor.py
@@ -29,6 +29,11 @@ import httpx
 import structlog
 
 from src.core.config import get_settings
+from src.services.ollama_endpoint_circuit_breaker import (
+    get_ollama_endpoint_cooldown_remaining_seconds,
+    record_ollama_endpoint_failure,
+    record_ollama_endpoint_success,
+)
 
 logger = structlog.get_logger(__name__)
 
@@ -206,9 +211,21 @@ class OllamaHealthMonitor:
 
     async def _run_checks(self, host: str) -> HealthReport:
         """依序執行三層檢查"""
+        cooldown_remaining = get_ollama_endpoint_cooldown_remaining_seconds(host)
+        if cooldown_remaining > 0:
+            return HealthReport(
+                status=HealthStatus.OFFLINE,
+                host=host,
+                reason=(
+                    "recent_endpoint_failure_cooldown:"
+                    f"{cooldown_remaining:.0f}s"
+                ),
+            )
+
         # 層 1：連通性
         connectivity_ok = await self._check_connectivity(host)
         if not connectivity_ok:
+            record_ollama_endpoint_failure(host)
             return HealthReport(
                 status=HealthStatus.OFFLINE,
                 host=host,
@@ -217,6 +234,7 @@ class OllamaHealthMonitor:
 
         # 層 2：推理測試
         report = await self._check_inference(host)
+        record_ollama_endpoint_success(host)
         return report
 
     async def _check_connectivity(self, host: str) -> bool:
diff --git a/apps/api/tests/test_health_ollama_provider_chain.py b/apps/api/tests/test_health_ollama_provider_chain.py
index 0aaabece..312a4bab 100644
--- a/apps/api/tests/test_health_ollama_provider_chain.py
+++ b/apps/api/tests/test_health_ollama_provider_chain.py
@@ -3,6 +3,19 @@ from __future__ import annotations
 import pytest
 
 from src.api.v1 import health
+from src.services.ollama_endpoint_circuit_breaker import (
+    is_ollama_endpoint_blocked,
+    record_ollama_endpoint_failure,
+    reset_ollama_endpoint_cooldown_for_tests,
+)
+
+
+def setup_function() -> None:
+    reset_ollama_endpoint_cooldown_for_tests()
+
+
+def teardown_function() -> None:
+    reset_ollama_endpoint_cooldown_for_tests()
 
 
 def _set_ollama_settings(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -66,3 +79,56 @@ def test_overall_status_uses_aggregate_ollama_not_endpoint_details() -> None:
     }
 
     assert health._determine_overall_status(components) == "degraded"
+
+
+@pytest.mark.asyncio
+async def test_ollama_provider_chain_uses_cooldown_after_failure(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    _set_ollama_settings(monkeypatch)
+    calls: list[str] = []
+
+    async def fake_http_check(name: str, _url: str, _path: str) -> health.ComponentHealth:
+        calls.append(name)
+        if name == "ollama_gcp_a":
+            return health.ComponentHealth(status="down", error="http 502")
+        return health.ComponentHealth(status="up", latency_ms=9.0)
+
+    monkeypatch.setattr(health, "_http_health_check", fake_http_check)
+
+    aggregate, details = await health.check_ollama_provider_chain()
+
+    assert aggregate.status == "degraded"
+    assert details["ollama_gcp_a"].status == "down"
+    assert is_ollama_endpoint_blocked("http://gcp-a:11434")
+
+    calls.clear()
+    aggregate, details = await health.check_ollama_provider_chain()
+
+    assert aggregate.status == "degraded"
+    assert details["ollama_gcp_a"].status == "down"
+    assert "cooldown" in (details["ollama_gcp_a"].error or "")
+    assert "ollama_gcp_a" not in calls
+    assert {"ollama_gcp_b", "ollama_local"} == set(calls)
+
+
+@pytest.mark.asyncio
+async def test_ollama_provider_chain_success_clears_cooldown(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    _set_ollama_settings(monkeypatch)
+    record_ollama_endpoint_failure("http://gcp-a:11434")
+    monkeypatch.setattr(
+        health,
+        "get_ollama_endpoint_cooldown_remaining_seconds",
+        lambda _url: 0.0,
+    )
+
+    async def fake_http_check(name: str, _url: str, _path: str) -> health.ComponentHealth:
+        return health.ComponentHealth(status="up", latency_ms=8.0)
+
+    monkeypatch.setattr(health, "_http_health_check", fake_http_check)
+
+    await health.check_ollama_provider_chain()
+
+    assert not is_ollama_endpoint_blocked("http://gcp-a:11434")
diff --git a/apps/api/tests/test_ollama_endpoint_circuit_breaker.py b/apps/api/tests/test_ollama_endpoint_circuit_breaker.py
index 4af0855f..1721c51f 100644
--- a/apps/api/tests/test_ollama_endpoint_circuit_breaker.py
+++ b/apps/api/tests/test_ollama_endpoint_circuit_breaker.py
@@ -4,6 +4,7 @@ from types import SimpleNamespace
 
 from src.services.ollama_endpoint_circuit_breaker import (
     filter_ollama_urls_with_cooldown,
+    get_ollama_endpoint_cooldown_remaining_seconds,
     is_ollama_endpoint_blocked,
     record_ollama_endpoint_failure,
     record_ollama_endpoint_success,
@@ -41,6 +42,26 @@ def test_cooldown_expires_and_success_clears_block() -> None:
     assert not is_ollama_endpoint_blocked("http://gcp-a:11434", now=201.0)
 
 
+def test_cooldown_remaining_seconds_expires_cleanly() -> None:
+    record_ollama_endpoint_failure("http://gcp-a:11434", cooldown_seconds=10.0, now=100.0)
+
+    assert (
+        get_ollama_endpoint_cooldown_remaining_seconds(
+            "http://gcp-a:11434",
+            now=103.0,
+        )
+        == 7.0
+    )
+    assert (
+        get_ollama_endpoint_cooldown_remaining_seconds(
+            "http://gcp-a:11434",
+            now=111.0,
+        )
+        == 0.0
+    )
+    assert not is_ollama_endpoint_blocked("http://gcp-a:11434", now=112.0)
+
+
 def test_all_blocked_returns_full_order_for_recovery_probe() -> None:
     urls = ("http://gcp-a:11434", "http://gcp-b:11434")
 
diff --git a/apps/api/tests/test_ollama_health_monitor.py b/apps/api/tests/test_ollama_health_monitor.py
index 740a438e..eb983176 100644
--- a/apps/api/tests/test_ollama_health_monitor.py
+++ b/apps/api/tests/test_ollama_health_monitor.py
@@ -19,16 +19,17 @@ OllamaHealthMonitor 單元測試 - P1.1c
 from __future__ import annotations
 
 import asyncio
-import json
-import time
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import httpx
 import pytest
 
+from src.services.ollama_endpoint_circuit_breaker import (
+    is_ollama_endpoint_blocked,
+    record_ollama_endpoint_failure,
+    reset_ollama_endpoint_cooldown_for_tests,
+)
 from src.services.ollama_health_monitor import (
-    LATENCY_HEALTHY_THRESHOLD_MS,
-    LATENCY_SLOW_THRESHOLD_MS,
     HealthReport,
     HealthStatus,
     OllamaHealthMonitor,
@@ -48,8 +49,10 @@ HOST_LOCAL = "http://192.168.0.111:11434"  # Local fallback（已移出 188 主
 @pytest.fixture(autouse=True)
 def reset_singleton():
     """每個測試後重置 singleton"""
+    reset_ollama_endpoint_cooldown_for_tests()
     yield
     reset_ollama_health_monitor()
+    reset_ollama_endpoint_cooldown_for_tests()
 
 
 @pytest.fixture
@@ -110,6 +113,29 @@ class TestConnectivity:
             result = await monitor._check_connectivity(HOST)
         assert result is False
 
+    @pytest.mark.asyncio
+    async def test_run_checks_records_connectivity_failure_cooldown(self, monitor, monkeypatch):
+        """連通性失敗會建立短暫 cooldown，避免重複撞同一個 upstream。"""
+        monkeypatch.setattr(monitor, "_check_connectivity", AsyncMock(return_value=False))
+
+        report = await monitor._run_checks(HOST)
+
+        assert report.status == HealthStatus.OFFLINE
+        assert is_ollama_endpoint_blocked(HOST)
+
+    @pytest.mark.asyncio
+    async def test_run_checks_respects_existing_failure_cooldown(self, monitor, monkeypatch):
+        """cooldown 中直接回報 OFFLINE，不再打 /api/tags。"""
+        record_ollama_endpoint_failure(HOST)
+        connectivity = AsyncMock(return_value=True)
+        monkeypatch.setattr(monitor, "_check_connectivity", connectivity)
+
+        report = await monitor._run_checks(HOST)
+
+        assert report.status == HealthStatus.OFFLINE
+        assert "cooldown" in report.reason
+        connectivity.assert_not_awaited()
+
     @pytest.mark.asyncio
     async def test_connectivity_timeout(self, monitor):
         """連線 timeout → 返回 False（不 raise）"""
@@ -160,7 +186,6 @@ class TestInference:
 
         # 模擬 0.5s 延遲（< 10s threshold）
         call_count = [0]
-        original_perf_counter = time.perf_counter
 
         def _fake_perf_counter():
             call_count[0] += 1
diff --git a/docs/LOGBOOK.md b/docs/LOGBOOK.md
index 050a6458..ab69b893 100644
--- a/docs/LOGBOOK.md
+++ b/docs/LOGBOOK.md
@@ -31,7 +31,8 @@
   - `knowledge_rag_service.py`
   - `playbook_rag.py`
 - 成功時會清除 cooldown；network/timeout/5xx 失敗才短暫標記，不因 4xx 或資料錯誤誤封 endpoint。
-- 前端/health/failover status 不套用 cooldown，仍會顯示 GCP-A/B 真實紅燈，不消音、不假裝 healthy。
+- health/failover status 也回報明確 cooldown/offline 狀態，仍保留 GCP-A/B 真實紅燈，不消音、不假裝 healthy。
+- `/api/v1/health` 的 provider chain 與 `OllamaHealthMonitor` 會在 endpoint 剛失敗後短暫回報 `recent endpoint failure cooldown`，避免每個健康頁、route 頁連續撞同一個 502。
 
 **local verification**：
 
@@ -49,6 +50,9 @@ pytest:
   test_ollama_endpoint_resolver.py
   test_playbook_service.py
   -> 23 passed
+  test_health_ollama_provider_chain.py
+  test_ollama_health_monitor.py
+  -> 35 passed
 git diff --check -> ok
 ```