diff --git a/src/main/frontend/fs/sync.cljs b/src/main/frontend/fs/sync.cljs
index 4559fea4f..9eba427bc 100644
--- a/src/main/frontend/fs/sync.cljs
+++ b/src/main/frontend/fs/sync.cljs
@@ -77,7 +77,28 @@
 (s/def ::TXContent string?)
 (s/def ::diff (s/keys :req-un [::TXId ::TXType ::TXContent]))
 
+(s/def ::succ-map #(= {:succ true} %))
+(s/def ::unknown-map (comp some? :unknown))
+(s/def ::stop-map #(= {:stop true} %))
+(s/def ::need-sync-remote #(= {:need-sync-remote true} %))
 
+(s/def ::sync-local->remote!-result
+  (s/or :succ ::succ-map
+        :need-sync-remote ::need-sync-remote
+        :unknown ::unknown-map))
+
+(s/def ::sync-remote->local!-result
+  (s/or :succ ::succ-map
+        :need-remote->local-full-sync
+        #(= {:need-remote->local-full-sync true} %)
+        :stop ::stop-map
+        :unknown ::unknown-map))
+
+(s/def ::sync-local->remote-all-files!-result
+  (s/or :succ ::succ-map
+        :stop ::stop-map
+        :need-sync-remote ::need-sync-remote
+        :unknown ::unknown-map))
 
 (def ws-addr "wss://og96xf1si7.execute-api.us-east-2.amazonaws.com/production?graphuuid=%s")
 
@@ -161,8 +182,8 @@
   [path]
   (let [parts (string/split path "/")]
     (if (and (< 2 (count parts))
-               (= 36 (count (parts 0)))
-               (= 36 (count (parts 1))))
+             (= 36 (count (parts 0)))
+             (= 36 (count (parts 1))))
       (string/join "/" (drop 2 parts))
       path)))
 
@@ -283,11 +304,11 @@
   NOTE: this xf should apply on reversed diffs sequence (sort by txid)"
   [n]
   (comp
-    (map diff->filetxns)
-    cat
-    distinct-update-filetxns-xf
-    remove-deleted-filetxns-xf
-    (partition-filetxns n)))
+   (map diff->filetxns)
+   cat
+   distinct-update-filetxns-xf
+   remove-deleted-filetxns-xf
+   (partition-filetxns n)))
 
 (defn- filepath->diff
   [index {:keys [relative-path user-uuid graph-uuid]}]
@@ -307,7 +328,6 @@
    (map-indexed filepath->diff)
    (diffs->partitioned-filetxns n)))
 
-
 (deftype FileMetadata [size etag path last-modified remote? ^:mutable normalized-path]
   Object
   (get-normalized-path [_]
@@ -460,10 +480,8 @@
          (retry-rsapi
           #(p->c (ipc/ipc "delete-remote-files" graph-uuid base-path filepaths local-txid token))))))))
 
-
 (def rsapi (->RSAPI))
 
-
 (deftype RemoteAPI []
   Object
 
@@ -555,9 +573,9 @@
               :Transactions
               (as-> txns
                   (sort-by :TXId txns)
-                  [txns
-                   (:TXId (last txns))
-                   (:TXId (first txns))]))))))
+                [txns
+                 (:TXId (last txns))
+                 (:TXId (first txns))]))))))
 
   (create-graph [this graph-name]
     (.request this "create_graph" {:GraphName graph-name}))
@@ -652,6 +670,8 @@
 
 
 ;; type = "change" | "add" | "unlink"
+
+
 (deftype FileChangeEvent [type dir path stat]
   IRelativePath
   (-relative-path [_] (remove-dir-prefix dir path))
@@ -706,8 +726,6 @@
   (sync-local->remote-all-files! [this] "compare all local files to remote ones, sync when not equal.
   if local-txid != remote-txid, return {:need-sync-remote true}"))
 
-
-
 (deftype Remote->LocalSyncer [graph-uuid base-path repo *txid *sync-state
                               ^:mutable local->remote-syncer *stopped]
   Object
@@ -789,12 +807,11 @@
             latest-txid (:TXId
                          (<! (get-remote-graph remoteapi nil graph-uuid)))]
         (println "[full-sync(remote->local)]"
-                       (count diff-remote-files) "files need to sync")
+                 (count diff-remote-files) "files need to sync")
         (<! (.sync-files-remote->local!
              this (map -relative-path diff-remote-files)
              latest-txid))))))
 
-
 (defn- file-changed?
   "return true when file changed compared with remote"
   [graph-uuid file-path-without-base-path base-path]
@@ -866,12 +883,13 @@
                 (async/close! c)))))
         c))
 
-    (sync-local->remote! [this es]
-      (if (empty? es)
-        {:succ true}
-        (let [type (.-type ^FileChangeEvent (first es))
-              ignore-files (get-ignore-files this)
-              es->paths-xf (comp
+
+  (sync-local->remote! [this es]
+    (if (empty? es)
+      (go {:succ true})
+      (let [type (.-type ^FileChangeEvent (first es))
+            ignore-files (get-ignore-files this)
+            es->paths-xf (comp
                             (map #(relative-path %))
                             (filter #(not (contains-path? ignore-files %))))
               paths (sequence es->paths-xf es)]
@@ -932,18 +950,19 @@
             (if stopped
               {:stop true}
               (if (empty? es-partitions)
-                {:succ true}
-                (let [{:keys [succ need-sync-remote unknown] :as r}
-                      (<! (sync-local->remote! this (first es-partitions)))]
-                  (cond
-                    succ
-                    (recur (next es-partitions))
-
+              {:succ true}
+              (let [{:keys [succ need-sync-remote unknown] :as r}
+                    (<! (sync-local->remote! this (first es-partitions)))]
+                (s/assert ::sync-local->remote!-result r)
+                (cond
+                  succ
+                  (recur (next es-partitions))
                     (or need-sync-remote unknown) r)))))))))
 
 
 ;;; sync state
 
+
 (defn sync-state
   "create a new sync-state"
   []
@@ -1003,6 +1022,7 @@
 
 ;;; put all stuff together
 
+
 (deftype ^:large-vars/cleanup-todo
     SyncManager [graph-uuid base-path *sync-state
                  ^Local->RemoteSyncer local->remote-syncer ^Remote->LocalSyncer remote->local-syncer
@@ -1067,8 +1087,9 @@
 
   (full-sync [this]
     (go
-      (let [{:keys [succ need-sync-remote unknown stop]}
+      (let [{:keys [succ need-sync-remote unknown stop] :as r}
             (<! (sync-local->remote-all-files! local->remote-syncer))]
+        (s/assert ::sync-local->remote-all-files!-result r)
         (cond
           succ
           (.schedule this ::idle nil)
@@ -1099,8 +1120,9 @@
     (go
       (if (some-> remote-val :txid (<= @*txid))
         (.schedule this ::idle nil)
-        (let [{:keys [succ unknown stop need-remote->local-full-sync]}
+        (let [{:keys [succ unknown stop need-remote->local-full-sync] :as r}
               (<! (sync-remote->local! remote->local-syncer))]
+          (s/assert ::sync-remote->local!-result r)
           (cond
             need-remote->local-full-sync
             (.schedule this ::remote->local-full-sync=>local->remote-full-sync nil)
@@ -1115,8 +1137,9 @@
   (local->remote [this {^FileChangeEvents local-change :local}]
     (assert (some? local-change) local-change)
     (go
-      (let [{:keys [succ need-sync-remote unknown]}
+      (let [{:keys [succ need-sync-remote unknown] :as r}
             (<! (sync-local->remote! local->remote-syncer [local-change]))]
+        (s/assert ::sync-local->remote!-result r)
         (cond
           succ
           (.schedule this ::idle nil)
@@ -1139,7 +1162,6 @@
       (debug/pprint ["stop sync-manager, graph-uuid" graph-uuid "base-path" base-path])
       (swap! *sync-state sync-state--update-state ::stop))))
 
-
 (defn sync-manager [graph-uuid base-path repo txid *sync-state full-sync-chan stop-sync-chan
                     remote->local-sync-chan local->remote-sync-chan local-changes-chan]
   (let [*txid (atom txid)
@@ -1157,13 +1179,11 @@
                    full-sync-chan stop-sync-chan
                    remote->local-sync-chan local->remote-sync-chan local-changes-chan nil *txid nil nil nil false)))
 
-
 (def full-sync-chan (chan 1))
 (def stop-sync-chan (chan 1))
 (def remote->local-sync-chan (chan))
 (def local->remote-sync-chan (chan))
 
-
 (defn sync-stop []
   (when-let [sm (state/get-file-sync-manager)]
     (println "stopping sync-manager")