diff --git a/calcit.cirru b/calcit.cirru
index cac3bac..7ece150 100644
--- a/calcit.cirru
+++ b/calcit.cirru
@@ -514,6 +514,7 @@
                         let
                             abort-controller $ unsafe-coerce abort 'Dynamic
                           do (js/console.warn |Aborting-prev) (.!abort abort-controller)
+                    , &unit
                 <> t
                 =< 8 nil
                 <> "|✕" style-abort-close
@@ -627,7 +628,7 @@
                               :preview $ decode-map-as @*viewing-archive-session 'app.schema/ChatSession
                           div
                             {} (:class-name style-archive-close)
-                              :on-click $ fn (e d!) (reset! *viewing-archive-session false)
+                              :on-click $ fn (e d!) (reset! *viewing-archive-session false) &unit
                             <> "|✕"
                         ; Messages list $ read only
                         div
@@ -670,7 +671,7 @@
                             :inner-text "|All Archived Sessions"
                           div
                             {} (:class-name style-archive-close)
-                              :on-click $ fn (e d!) (reset! *archived-sessions false) (reset! *viewing-archive-session false)
+                              :on-click $ fn (e d!) (reset! *archived-sessions false) (reset! *viewing-archive-session false) &unit
                             <> "|✕"
                         ; List
                         div
@@ -701,7 +702,7 @@
                                         div
                                           {} (:role |button)
                                             :style $ {} (:flex |1) (:cursor :pointer) (:min-width 0) (:overflow :hidden)
-                                            :on-click $ fn (e d!) (reset! *viewing-archive-session session)
+                                            :on-click $ fn (e d!) (reset! *viewing-archive-session session) &unit
                                           div
                                             {} $ :style
                                               {} (:font-size |12px)
@@ -728,6 +729,7 @@
                                                       archive-key $ :archive-key site
                                                     js-await $ db-set archive-key (format-cirru-edn new-archives)
                                                     d! $ :: :update-archived-count (count new-archives)
+                                              , &unit
                                           <> "|✕"
                     ; Else render normal chat view
                     div
@@ -742,7 +744,7 @@
                           div
                             {} (:class-name css/row-middle) (:title |History) (:role |button) (:aria-label |history-open)
                               :style $ {} (:cursor :pointer)
-                              :on-click $ fn (e d!) (.show sessions-plugin d!)
+                              :on-click $ fn (e d!) (.show sessions-plugin d!) &unit
                             div
                               {} $ :class-name style-history-button
                               comp-i |clock
@@ -807,6 +809,7 @@
                                   :on-click $ fn (e d!)
                                     .show reply-plugin d! $ fn (text)
                                       submit-message! cursor state text (:search? message-box-state) (:think? message-box-state) model d!
+                                    , &unit
                                 <> |Reply
                               if (:focus-mode? message-box-state) nil $ a
                                 {} (:class-name style-focus-link) (:inner-text |Focus) (:role |button) (:aria-label |focus-composer)
@@ -821,6 +824,7 @@
                                             get (>> states :message-box) :cursor
                                             []
                                           assoc message-box-state :focus-mode? true
+                                    , &unit
                             , nil
                           if (:loading? state)
                             div ({}) (comp-abort |Loading...)
@@ -847,6 +851,7 @@
                           :on-click $ fn (e d!)
                             ; d! $ :: :change-model
                             .show model-plugin d!
+                            , &unit
                         fn (text search? think? d!)
                           do
                             when
@@ -887,6 +892,7 @@
                   :on-click $ fn (e d!)
                     when chrome-extension? $ js/chrome.runtime.sendMessage
                       js-object (:action |fill-text) (:text text)
+                    , &unit
                 comp-i :send 12 :currentColor
           :examples $ []
           :schema $ :: 'Dynamic
@@ -915,6 +921,7 @@
                                   fn () $ .!focus
                                     unsafe-coerce (js/document.querySelector |#message) 'Dynamic
                                   , 0
+                              , &unit
                           <> $ if
                             blank? $ :content state
                             , "|Click to expand and type..." (:content state)
@@ -928,6 +935,7 @@
                           :on-input $ fn (e d!)
                             d! cursor $ assoc state :content
                               str $ option:unwrap-or (get e :value) |
+                            , &unit
                           :on-keydown $ fn (e d!)
                             if
                               and
@@ -936,6 +944,7 @@
                                   option:unwrap-or (get e :meta?) false
                                   option:unwrap-or (get e :ctrl?) false
                               on-submit (:content state) (:search? state) (:think? state) d!
+                            , &unit
                           :on-focus $ fn (e d!)
                             let
                                 target $ unsafe-coerce
@@ -951,6 +960,7 @@
                               if
                                 not $ unsafe-coerce (.!contains box-class |focus-within) 'Bool
                                 .!add box-class |focus-within
+                            , &unit
                           :on-blur $ fn (e d!)
                             let
                                 target $ unsafe-coerce
@@ -966,6 +976,7 @@
                               if
                                 unsafe-coerce (.!contains box-class |focus-within) 'Bool
                                 .!remove box-class |focus-within
+                            , &unit
                       if
                         not $ :focus-mode? state
                         do (=< nil 4)
@@ -980,6 +991,7 @@
                                 :on-click $ fn (e d!)
                                   d! cursor $ assoc state :content |
                                   .!focus $ unsafe-coerce (js/document.querySelector |#message) 'Dynamic
+                                  , &unit
                               span $ {} (:class-name style-clear)
                             div
                               {} $ :class-name (str-spaced css/row style-gap12)
@@ -992,6 +1004,7 @@
                                       :on-click $ fn (e d!)
                                         d! cursor $ assoc state :think?
                                           not $ :think? state
+                                        , &unit
                                     input $ {}
                                       :checked $ :think? state
                                       :type |checkbox
@@ -1005,6 +1018,7 @@
                                     :on-click $ fn (e d!)
                                       d! cursor $ assoc state :search?
                                         not $ :search? state
+                                      , &unit
                                   input $ {}
                                     :checked $ :search? state
                                     :type |checkbox
@@ -1016,6 +1030,7 @@
                                   :inner-text |Submit
                                   :on-click $ fn (e d!)
                                     on-submit (:content state) (:search? state) (:think? state) d!
+                                    , &unit
                         , nil
           :examples $ []
           :schema $ :: 'Fn
@@ -1044,7 +1059,7 @@
                       button
                         {} (:class-name css/button)
                           :style $ {} (:cursor :pointer)
-                          :on-click $ fn (e d!) (on-close d!) (on-view-archive d!)
+                          :on-click $ fn (e d!) (on-close d!) (on-view-archive d!) &unit
                         <> "|View Archive"
                   if (empty? sessions)
                     div
@@ -1071,7 +1086,7 @@
                                 {} (:role |button)
                                   :aria-label $ str |session-select: preview
                                   :style $ {} (:flex |1) (:cursor :pointer) (:min-width 0) (:overflow :hidden)
-                                  :on-click $ fn (e d!) (on-select session-id d!) (on-close d!)
+                                  :on-click $ fn (e d!) (on-select session-id d!) (on-close d!) &unit
                                 div
                                   {} $ :style
                                     {} (:font-size |12px)
@@ -1091,6 +1106,7 @@
                                           , 'Dynamic
                                       .!stopPropagation event
                                     d! $ :: :remove-session session-id
+                                    , &unit
                                 <> "|✕"
                   if
                     > (count sessions) 0
@@ -1103,9 +1119,9 @@
                         div
                           {} $ :class-name (str-spaced css/row css/gap8)
                           a $ {} (:class-name style-clear) (:inner-text |Data) (:role |button) (:aria-label |sessions-export-data)
-                            :on-click $ fn (e d!) (tab-echo! sessions :edn)
+                            :on-click $ fn (e d!) (tab-echo! sessions :edn) &unit
                           a $ {} (:class-name style-clear) (:inner-text |Download) (:role |button) (:aria-label |sessions-download)
-                            :on-click $ fn (e d!) (download-sessions! sessions)
+                            :on-click $ fn (e d!) (download-sessions! sessions) &unit
                         if
                           > (count sessions) 0
                           a $ {} (:class-name style-clear) (:inner-text "|Archive all") (:role |button) (:aria-label |sessions-archive-all)
@@ -1121,6 +1137,7 @@
                                     new-archives $ concat old-archives sessions
                                   js-await $ db-set archive-key (format-cirru-edn new-archives)
                                   d! $ :: :archive-sessions (count new-archives)
+                              , &unit
                           span $ {}
                       div $ {}
                         :style $ {} (:height 200)
@@ -1786,10 +1803,11 @@
                     :deepseek-v4-pro $ js-await (call-openrouter! cursor state1 prompt-text |deepseek-v4-pro true d! *text)
                     :deepseek-v4-flash $ js-await (call-openrouter! cursor state1 prompt-text |deepseek-v4-flash true d! *text)
                   fn (e)
-                    let
-                        err-text $ str "|Failed to load: " e
-                      d! cursor $ -> state (assoc :answer err-text) (assoc :loading? false) (assoc :done? true)
-                        assoc :messages $ upsert-assistant-message (:messages state) err-text nil
+                    do (js/console.error :msg-buffer-request-failed e)
+                      let
+                          err-text $ str |Failed-to-load: e
+                        d! cursor $ -> state (assoc :answer err-text) (assoc :loading? false) (assoc :done? true)
+                          assoc :messages $ upsert-assistant-message (:messages state) err-text nil
           :examples $ []
           :schema $ :: 'Fn
             {} (:return 'Dynamic)
diff --git a/deps.cirru b/deps.cirru
index fb0cb1d..f432d8c 100644
--- a/deps.cirru
+++ b/deps.cirru
@@ -1,9 +1,9 @@
 
-{} (:calcit-version |0.13.33)
+{} (:calcit-version |0.13.42)
   :version |0.0.3
   :dependencies $ {} (|Respo/alerts.calcit |0.10.19)
     |Respo/reel.calcit |0.6.7
     |Respo/respo-feather.calcit |0.4.4
-    |Respo/respo-markdown.calcit |0.4.24
+    |Respo/respo-markdown.calcit |0.4.25
     |Respo/respo-ui.calcit |0.7.10
-    |Respo/respo.calcit |0.16.83
+    |Respo/respo.calcit |0.16.85
diff --git a/history/20260824-upgrade-calcit-01340.md b/history/20260824-upgrade-calcit-01340.md
new file mode 100644
index 0000000..d394442
--- /dev/null
+++ b/history/20260824-upgrade-calcit-01340.md
@@ -0,0 +1,6 @@
+# 2026-08-24 Calcit 0.13.40 upgrade
+
+- Updated the Calcit compiler and `@calcit/procs` runtime to 0.13.40.
+- Updated Respo to 0.16.85 for the latest Calcit schema compatibility fixes.
+- Made DOM event handlers return `Unit` explicitly, matching Respo's typed event contract.
+- Revalidated type checks, quality checks, JavaScript generation, the production build, and Gemini streaming runtime calls.
diff --git a/history/202608241230-use-explicit-unit-event-handlers.md b/history/202608241230-use-explicit-unit-event-handlers.md
new file mode 100644
index 0000000..9204a00
--- /dev/null
+++ b/history/202608241230-use-explicit-unit-event-handlers.md
@@ -0,0 +1,8 @@
+# Use explicit Unit values for event handlers
+
+- Replaced the legacy `;nil` event-handler tails with Calcit's explicit
+  `&unit` literal after introducing the corresponding compiler support.
+- This makes UI callback returns semantically distinct from application `nil`;
+  the JavaScript backend emits `void 0` for the handlers.
+- Verified static checking, the project quality baseline, JS generation, Vite
+  production build, browser event interaction, and Gemini streaming requests.
diff --git a/history/202608241245-upgrade-calcit-01341.md b/history/202608241245-upgrade-calcit-01341.md
new file mode 100644
index 0000000..9c66818
--- /dev/null
+++ b/history/202608241245-upgrade-calcit-01341.md
@@ -0,0 +1,5 @@
+# Upgrade to Calcit 0.13.41
+
+- Upgraded the compiler and `@calcit/procs` runtime to the released 0.13.41.
+- This release provides the explicit `&unit` value used by the UI event
+  handlers, avoiding the legacy `;nil` compatibility form.
diff --git a/history/202608241320-upgrade-genai-error-logging.md b/history/202608241320-upgrade-genai-error-logging.md
new file mode 100644
index 0000000..77dad55
--- /dev/null
+++ b/history/202608241320-upgrade-genai-error-logging.md
@@ -0,0 +1,9 @@
+# Upgrade Gemini SDK and log request failures
+
+- Upgraded `@google/genai` to 2.18.0 and retained the streaming request shape
+  supported by the current SDK.
+- The top-level submit handler now writes the original caught error to
+  `console.error` before rendering the user-facing failure message, preserving
+  a useful browser debugging trail without exposing configured credentials.
+- The Markdown table renderer fix is released separately from respo-markdown;
+  msg-buffer will consume it after that package release.
diff --git a/package.json b/package.json
index bfbc31e..1682866 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "dependencies": {
-    "@calcit/procs": "^0.13.33",
-    "@google/genai": "^2.13.0",
+    "@calcit/procs": "^0.13.42",
+    "@google/genai": "^2.18.0",
     "@tiye/main-fonts": "0.0.1",
     "axios": "^1.15.0",
     "cirru-color": "^0.2.4",
diff --git a/yarn.lock b/yarn.lock
index 3235152..060cec2 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5,14 +5,14 @@ __metadata:
   version: 8
   cacheKey: 10c0
 
-"@calcit/procs@npm:^0.13.33":
-  version: 0.13.33
-  resolution: "@calcit/procs@npm:0.13.33"
+"@calcit/procs@npm:^0.13.42":
+  version: 0.13.42
+  resolution: "@calcit/procs@npm:0.13.42"
   dependencies:
     "@calcit/ternary-tree": "npm:0.0.26"
     "@cirru/parser.ts": "npm:^0.0.9"
     "@cirru/writer.ts": "npm:^0.1.9"
-  checksum: 10c0/132fa43ee4b5edb12bbdb04b11f528e73842752d2b7ec8dd716357129aa6e35f80fac35da87b8d09a17f0ad5f78572d8359bf7a9b7aa0c2cbc4e313569cdab6e
+  checksum: 10c0/14559120b68263b0c38a16fcb71f5898af837f1a32ab51abb30585f978e32eae150b6ad84491632a0dcb9ae7b800a48ab41370fba7e6efb3f92d8d88ad1069b1
   languageName: node
   linkType: hard
 
@@ -65,9 +65,9 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@google/genai@npm:^2.13.0":
-  version: 2.17.1
-  resolution: "@google/genai@npm:2.17.1"
+"@google/genai@npm:^2.18.0":
+  version: 2.18.0
+  resolution: "@google/genai@npm:2.18.0"
   dependencies:
     google-auth-library: "npm:^10.3.0"
     p-retry: "npm:^4.6.2"
@@ -78,7 +78,7 @@ __metadata:
   peerDependenciesMeta:
     "@modelcontextprotocol/sdk":
       optional: true
-  checksum: 10c0/f94efe55f23a10a1b54d0297a607747acc98d5ad1e26a4dabbc7a81869ef68bc15b2c056517b7870fa866fdb6aa77c7c39e8ce407e89dcac26ec363fb6a96aa2
+  checksum: 10c0/c3d1dafac8d467748504317bb3a11dbb219cffba3cfef7e371291d947c64f592a7367332b66278ff6c4ada8b7cfd7dbabf6622e8c49c6723dbd0317cbc317d37
   languageName: node
   linkType: hard
 
@@ -1573,8 +1573,8 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "root-workspace-0b6124@workspace:."
   dependencies:
-    "@calcit/procs": "npm:^0.13.33"
-    "@google/genai": "npm:^2.13.0"
+    "@calcit/procs": "npm:^0.13.42"
+    "@google/genai": "npm:^2.18.0"
     "@tiye/main-fonts": "npm:0.0.1"
     axios: "npm:^1.15.0"
     bottom-tip: "npm:^0.1.5"