diff --git a/js/src/chat/chat.scss b/js/src/chat/chat.scss
index c8f1cd8c..b1366fc9 100644
--- a/js/src/chat/chat.scss
+++ b/js/src/chat/chat.scss
@@ -167,7 +167,7 @@ shiny-chat-input {
       color: var(--bs-gray-600, #707782) !important;
     }
   }
-  button {
+  button.chat-send-button {
     position: absolute;
     bottom: calc(6px + var(--_input-padding-bottom));
     right: 8px;
diff --git a/js/src/chat/chat.ts b/js/src/chat/chat.ts
index d42b73d5..6f1e021b 100644
--- a/js/src/chat/chat.ts
+++ b/js/src/chat/chat.ts
@@ -224,7 +224,7 @@ class ChatInput extends LightElement {
   }
 
   private get button(): HTMLButtonElement {
-    return this.querySelector("button") as HTMLButtonElement
+    return this.querySelector("button.chat-send-button") as HTMLButtonElement
   }
 
   render() {
@@ -243,6 +243,7 @@ class ChatInput extends LightElement {
       ></textarea>
       <button
         type="button"
+        class="chat-send-button"
         title="Send message"
         aria-label="Send message"
         @click=${this.#sendInput}
diff --git a/pkg-py/src/shinychat/playwright/_chat.py b/pkg-py/src/shinychat/playwright/_chat.py
index 62718b14..8b065612 100644
--- a/pkg-py/src/shinychat/playwright/_chat.py
+++ b/pkg-py/src/shinychat/playwright/_chat.py
@@ -95,7 +95,7 @@ def __init__(self, page: Page, id: str) -> None:
         self.loc_latest_message = self.loc_messages.locator("> :last-child")
         self.loc_input_container = self.loc.locator("> shiny-chat-input")
         self.loc_input = self.loc_input_container.locator("textarea")
-        self.loc_input_button = self.loc_input_container.locator("button")
+        self.loc_input_button = self.loc_input_container.locator("button.chat-send-button")
 
     def expect_latest_message(
         self,