diff --git a/pi-coding-agent-menu.el b/pi-coding-agent-menu.el
index 3ce9d26..c705b08 100644
--- a/pi-coding-agent-menu.el
+++ b/pi-coding-agent-menu.el
@@ -314,6 +314,7 @@ Call this when starting a new session to ensure no stale state persists."
         pi-coding-agent--tool-block-order-counter 0
         pi-coding-agent--thinking-block-order-counter 0
         pi-coding-agent--activity-phase "idle")
+  (pi-coding-agent--clear-unsupported-extension-ui-warnings)
   (pi-coding-agent--invalidate-history-loads)
   ;; Use accessors for cross-module state
   (pi-coding-agent--clear-followup-queue)
diff --git a/pi-coding-agent-render.el b/pi-coding-agent-render.el
index 1665859..9fbc4f8 100644
--- a/pi-coding-agent-render.el
+++ b/pi-coding-agent-render.el
@@ -790,16 +790,36 @@ Shows success or final failure with raw error."
     (setq pi-coding-agent--working-message msg)
     (force-mode-line-update t)))
 
+(defconst pi-coding-agent--extension-ui-fire-and-forget-methods
+  '("notify" "setStatus" "setWidget" "setTitle" "set_editor_text"
+    "setWorkingMessage")
+  "Extension UI methods that do not expect RPC responses.")
+
+(defun pi-coding-agent--extension-ui-response-required-p (method)
+  "Return non-nil when unsupported extension UI METHOD may expect a response."
+  (not (member method pi-coding-agent--extension-ui-fire-and-forget-methods)))
+
+(defun pi-coding-agent--extension-ui-warn-unsupported-once (method)
+  "Warn at most once per pi session for unsupported extension UI METHOD."
+  (when (pi-coding-agent--record-unsupported-extension-ui-warning method)
+    (message "Pi: extension UI method `%s' not supported in Emacs" method)))
+
 (defun pi-coding-agent--extension-ui-unsupported (event proc)
-  "Handle unsupported method from EVENT by warning and sending cancelled via PROC.
+  "Handle unsupported method from EVENT, using PROC to cancel when needed.
+Warn at most once per method in a pi session.
+Dialog-like methods receive a cancelled response so extensions do not hang;
+fire-and-forget methods are only warned because they do not expect responses.
 See URL `https://github.com/dnouri/pi-coding-agent/issues/176'."
-  (message "Pi: extension UI method `%s' not supported in Emacs"
-           (plist-get event :method))
-  (when proc
-    (pi-coding-agent--send-extension-ui-response
-     proc (list :type "extension_ui_response"
-                :id (plist-get event :id)
-                :cancelled t))))
+  (let ((method (plist-get event :method))
+        (id (plist-get event :id)))
+    (pi-coding-agent--extension-ui-warn-unsupported-once method)
+    (when (and proc
+               id
+               (pi-coding-agent--extension-ui-response-required-p method))
+      (pi-coding-agent--send-extension-ui-response
+       proc (list :type "extension_ui_response"
+                  :id id
+                  :cancelled t)))))
 
 (defun pi-coding-agent--handle-extension-ui-request (event)
   "Handle extension_ui_request EVENT from pi.
diff --git a/pi-coding-agent-ui.el b/pi-coding-agent-ui.el
index 87c8898..0f93dd9 100644
--- a/pi-coding-agent-ui.el
+++ b/pi-coding-agent-ui.el
@@ -1115,6 +1115,20 @@ Keys are extension identifiers (strings), values are status text.")
 (defvar-local pi-coding-agent--working-message nil
   "Transient extension working message for header-line display.")
 
+(defvar-local pi-coding-agent--unsupported-extension-ui-methods-warned nil
+  "Unsupported extension UI method names already warned for this pi session.")
+
+(defun pi-coding-agent--record-unsupported-extension-ui-warning (method)
+  "Record an unsupported extension UI warning for METHOD.
+Return non-nil when METHOD had not already been warned for this pi session."
+  (unless (member method pi-coding-agent--unsupported-extension-ui-methods-warned)
+    (push method pi-coding-agent--unsupported-extension-ui-methods-warned)
+    t))
+
+(defun pi-coding-agent--clear-unsupported-extension-ui-warnings ()
+  "Forget unsupported extension UI warnings for the current pi session."
+  (setq pi-coding-agent--unsupported-extension-ui-methods-warned nil))
+
 (defvar-local pi-coding-agent--session-name nil
   "Cached session name for header-line display.
 Extracted from session_info entries when session is loaded or switched.")
@@ -1742,7 +1756,13 @@ Safely handles dead buffers by checking liveness first."
   (when (and (eq (plist-get response :success) t)
              (buffer-live-p chat-buf))
     (with-current-buffer chat-buf
-      (let ((new-state (pi-coding-agent--extract-state-from-response response)))
+      (let* ((old-session-id (plist-get pi-coding-agent--state :session-id))
+             (new-state (pi-coding-agent--extract-state-from-response response))
+             (new-session-id (plist-get new-state :session-id)))
+        (when (and old-session-id
+                   new-session-id
+                   (not (equal old-session-id new-session-id)))
+          (pi-coding-agent--clear-unsupported-extension-ui-warnings))
         (setq pi-coding-agent--status (plist-get new-state :status)
               pi-coding-agent--state new-state))
       (force-mode-line-update t))))
diff --git a/test/pi-coding-agent-menu-test.el b/test/pi-coding-agent-menu-test.el
index c06988a..d14cbf0 100644
--- a/test/pi-coding-agent-menu-test.el
+++ b/test/pi-coding-agent-menu-test.el
@@ -76,6 +76,7 @@
           pi-coding-agent--aborted t
           pi-coding-agent--extension-status '(("ext1" . "status"))
           pi-coding-agent--working-message "Reading README..."
+          pi-coding-agent--unsupported-extension-ui-methods-warned '("setWidget")
           pi-coding-agent--message-start-marker (point-marker)
           pi-coding-agent--streaming-marker (point-marker)
           pi-coding-agent--thinking-marker (point-marker)
@@ -102,6 +103,7 @@
     (should (null pi-coding-agent--aborted))
     (should (null pi-coding-agent--extension-status))
     (should (null pi-coding-agent--working-message))
+    (should (null pi-coding-agent--unsupported-extension-ui-methods-warned))
     (should (null pi-coding-agent--message-start-marker))
     (should (null pi-coding-agent--streaming-marker))
     (should (null pi-coding-agent--thinking-marker))
diff --git a/test/pi-coding-agent-render-test.el b/test/pi-coding-agent-render-test.el
index 93a2a2b..461cd36 100644
--- a/test/pi-coding-agent-render-test.el
+++ b/test/pi-coding-agent-render-test.el
@@ -1936,9 +1936,13 @@ since we don't display them locally. Let pi's message_start handle it."
 (ert-deftest pi-coding-agent-test-extension-ui-unsupported-warns ()
   "Unsupported extension_ui_request method warns via `message'.
 See https://github.com/dnouri/pi-coding-agent/issues/176."
-  (let (messages-logged response-sent)
+  (let (warnings-logged response-sent)
     (cl-letf (((symbol-function 'message)
-               (lambda (fmt &rest args) (push (apply #'format fmt args) messages-logged)))
+               (lambda (fmt &rest args)
+                 (when fmt
+                   (let ((msg (apply #'format fmt args)))
+                     (when (string-match-p "extension UI method" msg)
+                       (push msg warnings-logged))))))
               ((symbol-function 'pi-coding-agent--send-extension-ui-response)
                (lambda (_proc resp) (setq response-sent resp))))
       (with-temp-buffer
@@ -1948,12 +1952,87 @@ See https://github.com/dnouri/pi-coding-agent/issues/176."
            '(:type "extension_ui_request"
              :id "req-unknown"
              :method "someNewFancyWidget")))))
-    ;; Should warn the user
     (should (cl-some (lambda (m) (string-match-p "someNewFancyWidget" m))
-                     messages-logged))
-    ;; Should still send cancelled so the extension doesn't hang
+                     warnings-logged))
+    ;; Unknown methods may be future dialogs, so they are cancelled.
     (should response-sent)
-    (should (equal (plist-get response-sent :cancelled) t))))
+    (should (eq (plist-get response-sent :cancelled) t))))
+
+(ert-deftest pi-coding-agent-test-extension-ui-unsupported-warns-once-per-method ()
+  "Repeated unsupported extension_ui_request methods warn once per method."
+  (let (warnings-logged responses-sent)
+    (with-temp-buffer
+      (pi-coding-agent-chat-mode)
+      (cl-letf (((symbol-function 'message)
+                 (lambda (fmt &rest args)
+                   (when fmt
+                     (let ((msg (apply #'format fmt args)))
+                       (when (string-match-p "extension UI method" msg)
+                         (push msg warnings-logged))))))
+                ((symbol-function 'pi-coding-agent--send-extension-ui-response)
+                 (lambda (_proc resp) (push resp responses-sent))))
+        (let ((pi-coding-agent--process t))
+          (pi-coding-agent--handle-extension-ui-request
+           '(:type "extension_ui_request"
+             :id "req-widget-1"
+             :method "setWidget"
+             :widgetKey "my-ext"
+             :widgetLines ["Line 1"]))
+          (pi-coding-agent--handle-extension-ui-request
+           '(:type "extension_ui_request"
+             :id "req-widget-2"
+             :method "setWidget"
+             :widgetKey "my-ext"
+             :widgetLines ["Line 2"]))
+          (pi-coding-agent--handle-extension-ui-request
+           '(:type "extension_ui_request"
+             :id "req-title"
+             :method "setTitle"
+             :title "pi - project")))))
+    (should (= (length warnings-logged) 2))
+    (should (= 1 (cl-count-if (lambda (m) (string-match-p "setWidget" m))
+                              warnings-logged)))
+    (should (= 1 (cl-count-if (lambda (m) (string-match-p "setTitle" m))
+                              warnings-logged)))
+    ;; setWidget and setTitle are fire-and-forget RPC methods.
+    (should (null responses-sent))))
+
+(ert-deftest pi-coding-agent-test-extension-ui-unsupported-warnings-are-buffer-local ()
+  "Unsupported extension UI warning dedupe is isolated by chat buffer."
+  (let ((buf-a (generate-new-buffer "*test-extension-ui-a*"))
+        (buf-b (generate-new-buffer "*test-extension-ui-b*"))
+        warnings-logged)
+    (unwind-protect
+        (cl-letf (((symbol-function 'message)
+                   (lambda (fmt &rest args)
+                     (when fmt
+                       (let ((msg (apply #'format fmt args)))
+                         (when (string-match-p "extension UI method" msg)
+                           (push msg warnings-logged))))))
+                  ((symbol-function 'pi-coding-agent--send-extension-ui-response)
+                   #'ignore))
+          (dolist (buf (list buf-a buf-b))
+            (with-current-buffer buf
+              (pi-coding-agent-chat-mode)
+              (let ((pi-coding-agent--process t))
+                (pi-coding-agent--handle-extension-ui-request
+                 '(:type "extension_ui_request"
+                   :id "req-widget"
+                   :method "setWidget"
+                   :widgetKey "my-ext"
+                   :widgetLines ["Line 1"])))))
+          (with-current-buffer buf-a
+            (let ((pi-coding-agent--process t))
+              (pi-coding-agent--handle-extension-ui-request
+               '(:type "extension_ui_request"
+                 :id "req-widget-again"
+                 :method "setWidget"
+                 :widgetKey "my-ext"
+                 :widgetLines ["Line 2"]))))
+          (should (= 2 (cl-count-if (lambda (m) (string-match-p "setWidget" m))
+                                    warnings-logged))))
+      (when (buffer-live-p buf-a) (kill-buffer buf-a))
+      (when (buffer-live-p buf-b) (kill-buffer buf-b)))))
 
 (ert-deftest pi-coding-agent-test-header-format-extension-status ()
   "Extension status formatter returns inline neutral status text without pipe."
@@ -1987,9 +2066,7 @@ See https://github.com/dnouri/pi-coding-agent/issues/176."
           (pi-coding-agent--handle-extension-ui-request
            '(:type "extension_ui_request"
              :id "req-9"
-             :method "setWidget"
-             :widgetKey "my-ext"
-             :widgetLines ["Line 1"])))
+             :method "someNewFancyWidget")))
         (should response-sent)
         (should (equal (plist-get response-sent :type) "extension_ui_response"))
         (should (equal (plist-get response-sent :id) "req-9"))
diff --git a/test/pi-coding-agent-ui-test.el b/test/pi-coding-agent-ui-test.el
index 11c4827..28d0a08 100644
--- a/test/pi-coding-agent-ui-test.el
+++ b/test/pi-coding-agent-ui-test.el
@@ -1446,6 +1446,60 @@ Catches wiring bugs like requiring deleted modules."
       (should essential-called)
       (should optional-called))))
 
+;;; State response
+
+(ert-deftest pi-coding-agent-test-apply-state-response-preserves-extension-ui-warnings-without-session-change ()
+  "Applying state keeps unsupported UI warnings within the same pi session."
+  (let ((chat-buf (generate-new-buffer "*test-state-same-session*")))
+    (unwind-protect
+        (progn
+          (with-current-buffer chat-buf
+            (pi-coding-agent-chat-mode)
+            (setq pi-coding-agent--state nil
+                  pi-coding-agent--unsupported-extension-ui-methods-warned
+                  '("setWidget")))
+          (pi-coding-agent--apply-state-response
+           chat-buf
+           '(:success t :data (:isStreaming :false
+                               :sessionId "new-session"
+                               :sessionFile "/tmp/new.jsonl")))
+          (with-current-buffer chat-buf
+            (should (equal pi-coding-agent--unsupported-extension-ui-methods-warned
+                           '("setWidget"))))
+          (with-current-buffer chat-buf
+            (setq pi-coding-agent--unsupported-extension-ui-methods-warned
+                  '("setWidget")))
+          (pi-coding-agent--apply-state-response
+           chat-buf
+           '(:success t :data (:isStreaming :false
+                               :sessionId "new-session"
+                               :sessionFile "/tmp/newer.jsonl")))
+          (with-current-buffer chat-buf
+            (should (equal pi-coding-agent--unsupported-extension-ui-methods-warned
+                           '("setWidget")))))
+      (kill-buffer chat-buf))))
+
+(ert-deftest pi-coding-agent-test-apply-state-response-resets-extension-ui-warnings-on-session-change ()
+  "Applying state clears unsupported UI warnings when the pi session changes."
+  (let ((chat-buf (generate-new-buffer "*test-state-session-change*")))
+    (unwind-protect
+        (progn
+          (with-current-buffer chat-buf
+            (pi-coding-agent-chat-mode)
+            (setq pi-coding-agent--state '(:session-id "old-session")
+                  pi-coding-agent--unsupported-extension-ui-methods-warned
+                  '("setWidget")))
+          (pi-coding-agent--apply-state-response
+           chat-buf
+           '(:success t :data (:isStreaming :false
+                               :sessionId "new-session"
+                               :sessionFile "/tmp/new.jsonl")))
+          (with-current-buffer chat-buf
+            (should (equal (plist-get pi-coding-agent--state :session-id)
+                           "new-session"))
+            (should (null pi-coding-agent--unsupported-extension-ui-methods-warned))))
+      (kill-buffer chat-buf))))
+
 ;;; Input Window Height (integer and float ratio)
 
 (ert-deftest pi-coding-agent-test-input-height-integer-returns-configured-value ()