diff --git a/public/components/assistant.html b/public/components/assistant.html
index a1dfa72..071f3b4 100644
--- a/public/components/assistant.html
+++ b/public/components/assistant.html
@@ -62,10 +62,12 @@
                 <div id="assistant-attachments" class="assistant-attachments" aria-label="Attached images" hidden></div>
                 <div class="assistant-composer-footer">
                   <span id="assistant-autosave-state" class="assistant-autosave-state" aria-live="polite"></span>
-                  <label class="assistant-attach" for="assistant-attach-input" title="Attach up to 4 images (PNG, JPEG, WebP)"><i class="fas fa-paperclip"></i></label>
-                  <input type="file" id="assistant-attach-input" accept="image/png,image/jpeg,image/webp" multiple hidden>
-                  <button id="btn-assistant-voice" class="assistant-voice-btn" type="button" title="Voice conversation"><i class="fas fa-headset"></i></button>
-                  <button id="btn-assistant-mic" class="assistant-mic" type="button" title="Dictate your question"><i class="fas fa-microphone"></i></button>
+                  <div class="assistant-tools">
+                    <label class="assistant-attach" for="assistant-attach-input" title="Attach up to 4 images (PNG, JPEG, WebP)"><i class="fas fa-paperclip"></i></label>
+                    <input type="file" id="assistant-attach-input" accept="image/png,image/jpeg,image/webp" multiple hidden>
+                    <button id="btn-assistant-voice" class="assistant-voice-btn" type="button" title="Voice conversation"><i class="fas fa-headset"></i></button>
+                    <button id="btn-assistant-mic" class="assistant-mic" type="button" title="Dictate your question"><i class="fas fa-microphone"></i></button>
+                  </div>
                   <button id="btn-assistant-send" class="btn-send" type="submit"><i class="fas fa-arrow-up"></i></button>
                 </div>
               </form>
diff --git a/public/css/assistant.css b/public/css/assistant.css
index b37404e..c2761c7 100644
--- a/public/css/assistant.css
+++ b/public/css/assistant.css
@@ -271,9 +271,10 @@ body.assistant-workspace .assistant-learning-view { min-height: 0; height: 100vh
 .assistant-composer { border:1px solid var(--g200); border-radius:20px; box-shadow:0 8px 30px rgba(0,0,0,.08); padding:10px 14px 6px; display:flex; flex-direction:column; gap:2px; }
 .assistant-composer > label { display:none; }
 #assistant-input { flex:1 1 auto; border:none; outline:none; resize:none; background:transparent; font-size:15px; line-height:1.5; min-height:56px; max-height:180px; padding:6px 0; }
-.assistant-composer-footer { display:flex; align-items:center; justify-content:space-between; gap:4px; border-top:1px solid var(--g100); padding-top:4px; margin-top:2px; }
+.assistant-composer-footer { display:flex; align-items:center; gap:2px; border-top:1px solid var(--g100); padding-top:4px; margin-top:2px; }
+.assistant-composer-footer .assistant-tools { display:flex; align-items:center; gap:2px; margin-right:auto; }
 .assistant-composer-footer .assistant-attach, .assistant-composer-footer .assistant-voice-btn, .assistant-composer-footer .assistant-mic { width:30px; height:30px; font-size:14px; }
-.assistant-composer-footer .btn-send { width:32px; height:32px; font-size:14px; }
+.assistant-composer-footer .btn-send { width:32px; height:32px; font-size:14px; margin-left:auto; }
 .assistant-attach, .assistant-voice-btn, .assistant-mic { width:38px; height:38px; border:none; background:none; border-radius:50%; display:flex; align-items:center; justify-content:center; color:var(--g600); cursor:pointer; font-size:16px; }
 .assistant-attach:hover, .assistant-voice-btn:hover, .assistant-mic:hover { background:var(--g100); }
 .assistant-mic.recording { background:var(--danger,#dc2626); color:#fff; }
diff --git a/public/js/clinicalAssistant.js b/public/js/clinicalAssistant.js
index 1592aa0..450fb7d 100644
--- a/public/js/clinicalAssistant.js
+++ b/public/js/clinicalAssistant.js
@@ -963,6 +963,11 @@ import {
         }
       };
       if (typeof transcribeAudio === 'function' && blob && blob.size > 100) {
+        if (blob.size < 4000 && !live) {
+          if (typeof showToast === 'function') showToast('Recording was too short or silent — speak closer to the microphone', 'error');
+          finish('');
+          return;
+        }
         transcribeAudio(blob).then(function(data) {
           // Server transcription wins; the live transcript is the fallback,
           // never lose what the browser already heard.
@@ -1068,11 +1073,6 @@ import {
     resizeAssistantInput();
     if (status) status.textContent = 'Asking…';
     var send = document.getElementById('btn-assistant-send');
-    if (send) {
-      send.classList.toggle('busy', !!isBusy);
-      var sendIcon = send.querySelector('i');
-      if (sendIcon) sendIcon.className = isBusy ? 'fas fa-stop' : 'fas fa-arrow-up';
-    }
     if (send) send.click();
   }
 
@@ -2048,8 +2048,11 @@ import {
     }
     if (label) label.textContent = text || (isBusy ? 'Working...' : 'Ready');
     if (send) {
-      send.disabled = !!isBusy;
-      send.innerHTML = isBusy ? '<i class="fas fa-spinner fa-spin"></i> Searching' : '<i class="fas fa-paper-plane"></i> Ask';
+      // The send button becomes a clickable STOP while the assistant works.
+      send.classList.toggle('busy', !!isBusy);
+      var icon = send.querySelector('i');
+      if (icon) icon.className = isBusy ? 'fas fa-stop' : 'fas fa-arrow-up';
+      send.setAttribute('aria-label', isBusy ? 'Stop generating' : 'Send');
     }
     if (input) input.disabled = !!isBusy;
     if (attachInput) attachInput.disabled = !!isBusy;
diff --git a/test/assistant-message-actions.test.js b/test/assistant-message-actions.test.js
index ff4065e..e58f53c 100644
--- a/test/assistant-message-actions.test.js
+++ b/test/assistant-message-actions.test.js
@@ -86,6 +86,20 @@ test('regenerate replays the preceding question for the latest answer and never
   assert.match(all[all.length - 1].textContent, /Regenerated answer/);
 });
 
+test('the send button becomes a clickable stop icon while the assistant works', async t => {
+  const app = ui(t);
+  const c = app.context;
+  const send = app.document.getElementById('btn-assistant-send');
+  assert.equal(send.querySelector('i').className, 'fas fa-arrow-up');
+  c.setBusy(true, 'Working');
+  assert.equal(send.disabled, false, 'still clickable so it can cancel');
+  assert.ok(send.classList.contains('busy'));
+  assert.equal(send.querySelector('i').className, 'fas fa-stop');
+  c.setBusy(false, 'Ready');
+  assert.equal(send.querySelector('i').className, 'fas fa-arrow-up');
+  assert.ok(!send.classList.contains('busy'));
+});
+
 test('editing a user message returns the question to the composer', async t => {
   const app = ui(t);
   const c = app.context;