diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index 7c774ff17..7e5f1d43a 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -270,6 +270,15 @@ func (al *AgentLoop) ProcessHeartbeat(ctx context.Context, content, channel, cha
 }
 
 func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage) (string, error) {
+	// Filter out empty or whitespace-only messages
+	if strings.TrimSpace(msg.Content) == "" {
+		logger.DebugCF("agent", "Dropped empty message", map[string]any{
+			"channel":   msg.Channel,
+			"sender_id": msg.SenderID,
+		})
+		return "", nil
+	}
+
 	// Add message preview to log (show full content for error messages)
 	var logContent string
 	if strings.Contains(msg.Content, "Error:") || strings.Contains(msg.Content, "error") {
@@ -458,8 +467,7 @@ func (al *AgentLoop) runAgentLoop(ctx context.Context, agent *AgentInstance, opt
 	}
 
 	// 9. Log response
-	responsePreview := utils.Truncate(finalContent, 120)
-	logger.InfoCF("agent", fmt.Sprintf("Response: %s", responsePreview),
+	logger.InfoCF("agent", fmt.Sprintf("Response: [%s]", finalContent),
 		map[string]any{
 			"agent_id":     agent.ID,
 			"session_key":  opts.SessionKey,
diff --git a/pkg/channels/wecom_app.go b/pkg/channels/wecom_app.go
index 302603445..8f1dadd77 100644
--- a/pkg/channels/wecom_app.go
+++ b/pkg/channels/wecom_app.go
@@ -215,7 +215,15 @@ func (c *WeComAppChannel) Send(ctx context.Context, msg bus.OutboundMessage) err
 
 	accessToken := c.getAccessToken()
 	if accessToken == "" {
-		return fmt.Errorf("no valid access token available")
+		// Token expired or not yet acquired — attempt an on-demand refresh
+		logger.WarnC("wecom_app", "Access token missing or expired, attempting on-demand refresh")
+		if err := c.refreshAccessToken(); err != nil {
+			return fmt.Errorf("access token unavailable and refresh failed: %w", err)
+		}
+		accessToken = c.getAccessToken()
+		if accessToken == "" {
+			return fmt.Errorf("no valid access token available after refresh")
+		}
 	}
 
 	logger.DebugCF("wecom_app", "Sending message", map[string]any{
@@ -223,7 +231,7 @@ func (c *WeComAppChannel) Send(ctx context.Context, msg bus.OutboundMessage) err
 		"preview": utils.Truncate(msg.Content, 100),
 	})
 
-	return c.sendTextMessage(ctx, accessToken, msg.ChatID, msg.Content)
+	return c.sendMarkdownMessage(ctx, accessToken, msg.ChatID, msg.Content)
 }
 
 // handleWebhook handles incoming webhook requests from WeCom
@@ -453,14 +461,29 @@ func (c *WeComAppChannel) processMessage(ctx context.Context, msg WeComXMLMessag
 
 // tokenRefreshLoop periodically refreshes the access token
 func (c *WeComAppChannel) tokenRefreshLoop() {
-	ticker := time.NewTicker(5 * time.Minute)
-	defer ticker.Stop()
+	const fallbackInterval = 30 * time.Minute
+	const earlyRefresh = 5 * time.Minute
 
 	for {
+		// Calculate sleep duration based on current token expiry
+		c.tokenMu.RLock()
+		expiry := c.tokenExpiry
+		c.tokenMu.RUnlock()
+
+		var sleepDur time.Duration
+		if expiry.IsZero() {
+			// Token never successfully acquired
+			sleepDur = fallbackInterval
+		} else {
+			sleepDur = max(time.Until(expiry.Add(-earlyRefresh)),
+				// minimum 1 minute to avoid tight loop
+				time.Minute)
+		}
+
 		select {
 		case <-c.ctx.Done():
 			return
-		case <-ticker.C:
+		case <-time.After(sleepDur):
 			if err := c.refreshAccessToken(); err != nil {
 				logger.ErrorCF("wecom_app", "Failed to refresh access token", map[string]any{
 					"error": err.Error(),