diff --git a/backend/app/services/provider_usage.py b/backend/app/services/provider_usage.py
index 8e94a8e..92d3206 100644
--- a/backend/app/services/provider_usage.py
+++ b/backend/app/services/provider_usage.py
@@ -58,12 +58,11 @@ from app.core.time import utcnow
 logger = get_logger(__name__)
 
 CACHE_TTL_SECONDS = 60
-# Anthropic's subscription endpoint rate-limit window is ~30-60s.  Retrying
-# sooner than that (old 5s value) creates a tight retry loop that keeps the
-# rate limit permanently throttled.  Use the same 60s TTL as successes so the
-# next auto-poll only fires after the window has cleared.  Manual refreshes
-# (force_refresh=True) always bypass this TTL.
-CACHE_TTL_FAILURE_SECONDS = 60
+# Anthropic's oauth/usage endpoint requires User-Agent: claude-code/<ver> and
+# enforces a ~180s poll floor — callers without the correct UA hit an aggressive
+# bucket that 429s indefinitely.  Keep the failure TTL at 180s so we never
+# retry faster than that floor.  Manual refreshes (force_refresh=True) bypass.
+CACHE_TTL_FAILURE_SECONDS = 180
 STALE_SUBSCRIPTION_TTL_SECONDS = 10 * 60
 REQUEST_TIMEOUT = 8.0  # seconds
 
@@ -768,7 +767,7 @@ async def _fetch_anthropic_subscription(session_key: str) -> list[SubscriptionWi
     """
     headers = {
         "Authorization": f"Bearer {session_key}",
-        "User-Agent": "pipeline",
+        "User-Agent": "claude-code/1.0.0",
         "Accept": "application/json",
         "anthropic-version": "2023-06-01",
         "anthropic-beta": "oauth-2025-04-20",