diff --git a/docs/my-website/docs/proxy/config_settings.md b/docs/my-website/docs/proxy/config_settings.md
index cc9090c2de6..30c01a7b94f 100644
--- a/docs/my-website/docs/proxy/config_settings.md
+++ b/docs/my-website/docs/proxy/config_settings.md
@@ -396,6 +396,7 @@ router_settings:
 | guardrail_list | List[GuardrailTypedDict] | List of guardrail configurations for guardrail load balancing. Enables load balancing across multiple guardrail deployments with the same guardrail_name. [Further Docs](./guardrails/guardrail_load_balancing.md) |
 | enable_health_check_routing | boolean | If true, enables health check-driven deployment filtering to avoid routing requests to unhealthy deployments |
 | health_check_staleness_threshold | integer | Maximum age in seconds for cached health check results before marking deployments as stale |
+| health_check_ignore_transient_errors | boolean | If true, 429 (rate limit) and 408 (timeout) health check failures are ignored and do not affect routing or cooldown |
 
 
 ### environment variables - Reference
diff --git a/litellm/proxy/health_check.py b/litellm/proxy/health_check.py
index aeabe492f54..9895eeb66ea 100644
--- a/litellm/proxy/health_check.py
+++ b/litellm/proxy/health_check.py
@@ -21,6 +21,7 @@ ILLEGAL_DISPLAY_PARAMS = [
     "vertex_credentials",
     "aws_access_key_id",
     "aws_secret_access_key",
+    "exception",  # internal; not JSON-serializable, never for display
 ]
 
 MINIMAL_DISPLAY_PARAMS = ["model", "mode_error"]
diff --git a/tests/test_litellm/router_utils/test_router_health_check_routing.py b/tests/test_litellm/router_utils/test_router_health_check_routing.py
index f40144b44c9..b87a39ac1de 100644
--- a/tests/test_litellm/router_utils/test_router_health_check_routing.py
+++ b/tests/test_litellm/router_utils/test_router_health_check_routing.py
@@ -50,6 +50,7 @@ class TestFilterHealthCheckUnhealthyDeployments:
             def __init__(self):
                 self.enable_health_check_routing = enable
                 self.health_state_cache = health_cache
+                self.allowed_fails_policy = None
 
         # Import the actual method and bind it
         from litellm.router import Router
@@ -125,6 +126,7 @@ class TestAsyncFilterHealthCheckUnhealthyDeployments:
             def __init__(self):
                 self.enable_health_check_routing = enable
                 self.health_state_cache = health_cache
+                self.allowed_fails_policy = None
 
         fake = FakeRouter()
         fake._async_filter_health_check_unhealthy_deployments = (