diff --git a/internal/handler/custom_agent.go b/internal/handler/custom_agent.go
index 76a17366..12cc78ba 100644
--- a/internal/handler/custom_agent.go
+++ b/internal/handler/custom_agent.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/Tencent/WeKnora/internal/application/service"
 	"github.com/Tencent/WeKnora/internal/errors"
+	"github.com/Tencent/WeKnora/internal/im"
 	"github.com/Tencent/WeKnora/internal/logger"
 	"github.com/Tencent/WeKnora/internal/types"
 	"github.com/Tencent/WeKnora/internal/types/interfaces"
@@ -18,6 +19,7 @@ import (
 // CustomAgentHandler defines the HTTP handler for custom agent operations
 type CustomAgentHandler struct {
 	service      interfaces.CustomAgentService
+	imService    *im.Service
 	disabledRepo interfaces.TenantDisabledSharedAgentRepository
 	// userService 仅用于 list 接口批量回填 creator_name，作用见
 	// KnowledgeBaseHandler.userService。
@@ -27,11 +29,13 @@ type CustomAgentHandler struct {
 // NewCustomAgentHandler creates a new custom agent handler instance
 func NewCustomAgentHandler(
 	service interfaces.CustomAgentService,
+	imService *im.Service,
 	disabledRepo interfaces.TenantDisabledSharedAgentRepository,
 	userService interfaces.UserService,
 ) *CustomAgentHandler {
 	return &CustomAgentHandler{
 		service:      service,
+		imService:    imService,
 		disabledRepo: disabledRepo,
 		userService:  userService,
 	}
@@ -375,6 +379,20 @@ func (h *CustomAgentHandler) DeleteAgent(c *gin.Context) {
 
 	logger.Infof(ctx, "Deleting custom agent, ID: %s", secutils.SanitizeForLog(id))
 
+	tenantID, ok := types.TenantIDFromContext(ctx)
+	if !ok {
+		c.Error(errors.NewUnauthorizedError("Unauthorized"))
+		return
+	}
+
+	if err := h.imService.DeleteChannelsByAgent(id, tenantID); err != nil {
+		logger.ErrorWithFields(ctx, err, map[string]interface{}{
+			"agent_id": id,
+		})
+		c.Error(errors.NewInternalServerError("Failed to delete agent IM channels"))
+		return
+	}
+
 	// Delete the agent
 	err := h.service.DeleteAgent(ctx, id)
 	if err != nil {
diff --git a/internal/im/service.go b/internal/im/service.go
index ed03e454..b77c67ca 100644
--- a/internal/im/service.go
+++ b/internal/im/service.go
@@ -2248,19 +2248,25 @@ type ChannelWithAgent struct {
 // ListChannelsByTenant returns all non-deleted IM channels in the given tenant,
 // joined with custom_agents.name. Built-in agent IDs (whose rows may not exist
 // in custom_agents) produce an empty AgentName — the frontend can substitute a
-// localized "builtin agent" label in that case.
+// localized "builtin agent" label in that case. Channels whose custom agent was
+// soft-deleted are excluded so overview lists stay consistent after agent removal.
 func (s *Service) ListChannelsByTenant(tenantID uint64) ([]ChannelWithAgent, error) {
+	builtinIDs := types.GetBuiltinAgentIDs()
 	var rows []ChannelWithAgent
-	err := s.db.Table("im_channels AS c").
+	q := s.db.Table("im_channels AS c").
 		Select(`c.id, c.tenant_id, c.agent_id,
                 COALESCE(a.name, '') AS agent_name,
                 c.platform, c.name, c.enabled, c.mode, c.output_mode,
                 c.session_mode, c.bot_identity, c.created_at, c.updated_at`).
 		Joins(`LEFT JOIN custom_agents AS a
-               ON a.id = c.agent_id AND a.tenant_id = c.tenant_id`).
-		Where("c.tenant_id = ? AND c.deleted_at IS NULL", tenantID).
-		Order("c.created_at DESC").
-		Scan(&rows).Error
+               ON a.id = c.agent_id AND a.tenant_id = c.tenant_id AND a.deleted_at IS NULL`).
+		Where("c.tenant_id = ? AND c.deleted_at IS NULL", tenantID)
+	if len(builtinIDs) > 0 {
+		q = q.Where("a.id IS NOT NULL OR c.agent_id IN ?", builtinIDs)
+	} else {
+		q = q.Where("a.id IS NOT NULL")
+	}
+	err := q.Order("c.created_at DESC").Scan(&rows).Error
 	if err != nil {
 		return nil, err
 	}
@@ -2303,6 +2309,25 @@ func (s *Service) UpdateChannel(channel *IMChannel) error {
 	return nil
 }
 
+// DeleteChannelsByAgent stops and soft-deletes every IM channel bound to the
+// given agent within the tenant. Used when a custom agent is removed so
+// overview lists and running adapters do not outlive the agent.
+func (s *Service) DeleteChannelsByAgent(agentID string, tenantID uint64) error {
+	var channels []IMChannel
+	if err := s.db.Where("agent_id = ? AND tenant_id = ? AND deleted_at IS NULL", agentID, tenantID).
+		Find(&channels).Error; err != nil {
+		return err
+	}
+	for i := range channels {
+		s.StopChannel(channels[i].ID)
+	}
+	if len(channels) == 0 {
+		return nil
+	}
+	return s.db.Where("agent_id = ? AND tenant_id = ? AND deleted_at IS NULL", agentID, tenantID).
+		Delete(&IMChannel{}).Error
+}
+
 // DeleteChannel soft-deletes a channel and stops it. Only deletes if the channel belongs to the given tenant.
 func (s *Service) DeleteChannel(channelID string, tenantID uint64) error {
 	s.StopChannel(channelID)