diff --git a/internal/watcher/health/monitor/agent_proxied.go b/internal/watcher/health/monitor/agent_proxied.go
index 36b12c2a..7b782144 100644
--- a/internal/watcher/health/monitor/agent_proxied.go
+++ b/internal/watcher/health/monitor/agent_proxied.go
@@ -5,12 +5,13 @@ import (
 
 	agentPkg "github.com/yusing/godoxy/agent/pkg/agent"
 	"github.com/yusing/godoxy/internal/types"
+	"github.com/yusing/goutils/synk"
 )
 
 type (
 	AgentProxiedMonitor struct {
 		agent *agentPkg.AgentConfig
-		query string
+		query synk.Value[string]
 		*monitor
 	}
 	AgentCheckHealthTarget struct {
@@ -47,14 +48,14 @@ func (target *AgentCheckHealthTarget) displayURL() *url.URL {
 func NewAgentProxiedMonitor(agent *agentPkg.AgentConfig, config *types.HealthCheckConfig, target *AgentCheckHealthTarget) *AgentProxiedMonitor {
 	mon := &AgentProxiedMonitor{
 		agent: agent,
-		query: target.buildQuery(),
 	}
 	mon.monitor = newMonitor(target.displayURL(), config, mon.CheckHealth)
+	mon.query.Store(target.buildQuery())
 	return mon
 }
 
 func (mon *AgentProxiedMonitor) CheckHealth() (types.HealthCheckResult, error) {
-	resp, err := mon.agent.DoHealthCheck(mon.config.Timeout, mon.query)
+	resp, err := mon.agent.DoHealthCheck(mon.config.Timeout, mon.query.Load())
 	result := types.HealthCheckResult{
 		Healthy: resp.Healthy,
 		Detail:  resp.Detail,
@@ -62,3 +63,9 @@ func (mon *AgentProxiedMonitor) CheckHealth() (types.HealthCheckResult, error) {
 	}
 	return result, err
 }
+
+func (mon *AgentProxiedMonitor) UpdateURL(url *url.URL) {
+	mon.monitor.UpdateURL(url)
+	newTarget := AgentTargetFromURL(url)
+	mon.query.Store(newTarget.buildQuery())
+}
diff --git a/internal/watcher/health/monitor/docker.go b/internal/watcher/health/monitor/docker.go
index 5212f6d9..fba9ee44 100644
--- a/internal/watcher/health/monitor/docker.go
+++ b/internal/watcher/health/monitor/docker.go
@@ -2,6 +2,7 @@ package monitor
 
 import (
 	"net/http"
+	"net/url"
 
 	"github.com/bytedance/sonic"
 	"github.com/docker/docker/api/types/container"
@@ -49,6 +50,13 @@ func (mon *DockerHealthMonitor) Start(parent task.Parent) gperr.Error {
 	return nil
 }
 
+func (mon *DockerHealthMonitor) UpdateURL(url *url.URL) {
+	mon.monitor.UpdateURL(url)
+	if mon.fallback != nil {
+		mon.fallback.UpdateURL(url)
+	}
+}
+
 func (mon *DockerHealthMonitor) interceptInspectResponse(resp *http.Response) (intercepted bool, err error) {
 	if resp.StatusCode != http.StatusOK {
 		return false, nil
diff --git a/internal/watcher/health/monitor/monitor.go b/internal/watcher/health/monitor/monitor.go
index 5c9575a5..f1b29556 100644
--- a/internal/watcher/health/monitor/monitor.go
+++ b/internal/watcher/health/monitor/monitor.go
@@ -186,6 +186,10 @@ func (mon *monitor) Finish(reason any) {
 
 // UpdateURL implements HealthChecker.
 func (mon *monitor) UpdateURL(url *url.URL) {
+	if url == nil {
+		log.Warn().Msg("attempting to update health monitor URL with nil")
+		return
+	}
 	mon.url.Store(url)
 }