diff --git a/internal/gateway/methods/teams.go b/internal/gateway/methods/teams.go
index a00c865b..c8d91ca1 100644
--- a/internal/gateway/methods/teams.go
+++ b/internal/gateway/methods/teams.go
@@ -47,6 +47,7 @@ func (m *TeamsMethods) Register(router *gateway.MethodRouter) {
 	router.Register(protocol.MethodTeamsGet, m.handleGet)
 	router.Register(protocol.MethodTeamsDelete, m.handleDelete)
 	router.Register(protocol.MethodTeamsTaskList, m.handleTaskList)
+	router.Register(protocol.MethodTeamsTaskActiveBySession, m.handleTaskActiveBySession)
 	router.Register(protocol.MethodTeamsTaskApprove, m.handleTaskApprove)
 	router.Register(protocol.MethodTeamsTaskReject, m.handleTaskReject)
 	router.Register(protocol.MethodTeamsMembersAdd, m.handleAddMember)
diff --git a/internal/gateway/methods/teams_crud.go b/internal/gateway/methods/teams_crud.go
index 58bcf229..392a882a 100644
--- a/internal/gateway/methods/teams_crud.go
+++ b/internal/gateway/methods/teams_crud.go
@@ -195,6 +195,68 @@ func (m *TeamsMethods) handleTaskList(ctx context.Context, client *gateway.Clien
 	}))
 }
 
+// --- Active Tasks by Session ---
+
+func (m *TeamsMethods) handleTaskActiveBySession(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
+	if m.teamStore == nil {
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
+		return
+	}
+
+	var params struct {
+		SessionKey string `json:"sessionKey"`
+	}
+	if err := json.Unmarshal(req.Params, &params); err != nil {
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
+		return
+	}
+	if params.SessionKey == "" {
+		client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{"tasks": []any{}}))
+		return
+	}
+
+	tasks, err := m.teamStore.ListActiveTasksByChatID(ctx, params.SessionKey)
+	if err != nil {
+		slog.Warn("teams.tasks.active-by-session failed", "session_key", params.SessionKey, "error", err)
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
+		return
+	}
+
+	// Map to lightweight ActiveTeamTask shape for the sidebar
+	type activeTask struct {
+		TaskID           string `json:"taskId"`
+		TaskNumber       int    `json:"taskNumber"`
+		Subject          string `json:"subject"`
+		Status           string `json:"status"`
+		OwnerAgentKey    string `json:"ownerAgentKey,omitempty"`
+		OwnerDisplayName string `json:"ownerDisplayName,omitempty"`
+		ProgressPercent  int    `json:"progressPercent,omitempty"`
+		ProgressStep     string `json:"progressStep,omitempty"`
+		CommentCount     int    `json:"commentCount,omitempty"`
+		AttachmentCount  int    `json:"attachmentCount,omitempty"`
+	}
+
+	result := make([]activeTask, 0, len(tasks))
+	for _, t := range tasks {
+		result = append(result, activeTask{
+			TaskID:          t.ID.String(),
+			TaskNumber:      t.TaskNumber,
+			Subject:         t.Subject,
+			Status:          t.Status,
+			OwnerAgentKey:   t.OwnerAgentKey,
+			ProgressPercent: t.ProgressPercent,
+			ProgressStep:    t.ProgressStep,
+			CommentCount:    t.CommentCount,
+			AttachmentCount: t.AttachmentCount,
+		})
+	}
+
+	client.SendResponse(protocol.NewOKResponse(req.ID, map[string]any{
+		"tasks": result,
+	}))
+}
+
 // --- Update (settings) ---
 
 type teamsUpdateParams struct {
diff --git a/internal/store/pg/teams_tasks.go b/internal/store/pg/teams_tasks.go
index d879ce0c..bcd2ba0d 100644
--- a/internal/store/pg/teams_tasks.go
+++ b/internal/store/pg/teams_tasks.go
@@ -456,6 +456,36 @@ func (s *PGTeamStore) DeleteTasks(ctx context.Context, taskIDs []uuid.UUID, team
 	return deleted, rows.Err()
 }
 
+// ListActiveTasksByChatID returns non-terminal tasks for a given chat_id (session key).
+// Used to restore the active tasks sidebar when switching back to a session.
+func (s *PGTeamStore) ListActiveTasksByChatID(ctx context.Context, chatID string) ([]store.TeamTaskData, error) {
+	if chatID == "" {
+		return nil, nil
+	}
+	args := []any{chatID}
+	tenantWhere := ""
+	if !store.IsCrossTenant(ctx) {
+		tid := store.TenantIDFromContext(ctx)
+		if tid == uuid.Nil {
+			return nil, fmt.Errorf("tenant_id required")
+		}
+		tenantWhere = fmt.Sprintf(" AND t.tenant_id = $%d", len(args)+1)
+		args = append(args, tid)
+	}
+	rows, err := s.db.QueryContext(ctx,
+		`SELECT `+taskSelectCols+`
+		 `+taskJoinClause+`
+		 WHERE COALESCE(t.chat_id,'') = $1
+		   AND t.status IN ('pending','in_progress','blocked','in_review')`+tenantWhere+`
+		 ORDER BY t.task_number ASC
+		 LIMIT 50`, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	return scanTaskRowsJoined(rows)
+}
+
 func scanTaskRowsJoined(rows *sql.Rows) ([]store.TeamTaskData, error) {
 	var tasks []store.TeamTaskData
 	for rows.Next() {
diff --git a/internal/store/team_store.go b/internal/store/team_store.go
index f0189766..0ce69809 100644
--- a/internal/store/team_store.go
+++ b/internal/store/team_store.go
@@ -231,6 +231,7 @@ type TaskStore interface {
 	UpdateTaskProgress(ctx context.Context, taskID, teamID uuid.UUID, percent int, step string) error
 	RenewTaskLock(ctx context.Context, taskID, teamID uuid.UUID) error
 	ResetTaskStatus(ctx context.Context, taskID, teamID uuid.UUID) error
+	ListActiveTasksByChatID(ctx context.Context, chatID string) ([]TeamTaskData, error)
 }
 
 // TaskCommentStore manages task comments, audit events, and attachments.
diff --git a/pkg/protocol/methods.go b/pkg/protocol/methods.go
index cd1eecbe..6ddb7388 100644
--- a/pkg/protocol/methods.go
+++ b/pkg/protocol/methods.go
@@ -136,7 +136,8 @@ const (
 	MethodTeamsTaskCreate    = "teams.tasks.create"
 	MethodTeamsTaskDelete     = "teams.tasks.delete"
 	MethodTeamsTaskDeleteBulk = "teams.tasks.delete-bulk"
-	MethodTeamsTaskAssign     = "teams.tasks.assign"
+	MethodTeamsTaskAssign            = "teams.tasks.assign"
+	MethodTeamsTaskActiveBySession   = "teams.tasks.active-by-session"
 	MethodTeamsMembersAdd    = "teams.members.add"
 	MethodTeamsMembersRemove = "teams.members.remove"
 	MethodTeamsUpdate        = "teams.update"
diff --git a/ui/web/src/api/protocol.ts b/ui/web/src/api/protocol.ts
index ae600172..34bb536b 100644
--- a/ui/web/src/api/protocol.ts
+++ b/ui/web/src/api/protocol.ts
@@ -143,6 +143,7 @@ export const Methods = {
   TEAMS_TASK_DELETE: "teams.tasks.delete",
   TEAMS_TASK_DELETE_BULK: "teams.tasks.delete-bulk",
   TEAMS_TASK_ASSIGN: "teams.tasks.assign",
+  TEAMS_TASK_ACTIVE_BY_SESSION: "teams.tasks.active-by-session",
   TEAMS_MEMBERS_ADD: "teams.members.add",
   TEAMS_MEMBERS_REMOVE: "teams.members.remove",
   TEAMS_UPDATE: "teams.update",
diff --git a/ui/web/src/pages/chat/hooks/use-chat-messages.ts b/ui/web/src/pages/chat/hooks/use-chat-messages.ts
index 26ff3157..bf502c99 100644
--- a/ui/web/src/pages/chat/hooks/use-chat-messages.ts
+++ b/ui/web/src/pages/chat/hooks/use-chat-messages.ts
@@ -139,12 +139,18 @@ export function useChatMessages(sessionKey: string, agentId: string) {
     }
   }, [ws, agentId, sessionKey]);
 
-  // Load history when session changes
+  // Load history and restore active tasks when session changes
   useEffect(() => {
     if (sessionKey) {
       loadHistory();
+      // Restore active team tasks (fire-and-forget — teams module may not be configured)
+      ws.call<{ tasks?: ActiveTeamTask[] }>(Methods.TEAMS_TASK_ACTIVE_BY_SESSION, { sessionKey })
+        .then((res) => {
+          if (res.tasks && res.tasks.length > 0) setTeamTasks(res.tasks);
+        })
+        .catch(() => {}); // teams not configured or RPC not registered
     }
-  }, [sessionKey, loadHistory]);
+  }, [sessionKey, loadHistory, ws]);
 
   // Called before sending a message so the event handler knows to capture run.started
   const expectRun = useCallback(() => {