diff --git a/renderer/css/style.css b/renderer/css/style.css
index b6978eb..714217f 100644
--- a/renderer/css/style.css
+++ b/renderer/css/style.css
@@ -762,6 +762,23 @@ html, body {
 
 .send-btn:active, .ptt-btn:active { transform: translateY(0); }
 .send-btn:disabled { background: var(--text-muted); cursor: not-allowed; opacity: 0.5; }
+.send-btn.hidden { display: none !important; }
+
+.stop-btn {
+  width: 42px; height: 42px;
+  background: var(--surface2);
+  border: 1px solid var(--border);
+  border-radius: 2px;
+  color: #ef4444;
+  cursor: pointer;
+  display: flex; align-items: center; justify-content: center;
+  font-size: 18px;
+  transition: all 0.15s;
+  flex-shrink: 0;
+}
+.stop-btn:hover { background: rgba(239, 68, 68, 0.15); border-color: #ef4444; }
+.stop-btn:active { transform: translateY(0); }
+.stop-btn.hidden { display: none !important; }
 
 /* ── Bottom toolbar ──────────────────────────────────────────────────────── */
 .ptt-btn .waveform {
diff --git a/renderer/index.html b/renderer/index.html
index 1f17776..3cd7e7e 100644
--- a/renderer/index.html
+++ b/renderer/index.html
@@ -89,6 +89,7 @@
         </span>
       </button>
       <button class="send-btn" id="send-btn" title="Send">➤</button>
+      <button class="stop-btn hidden" id="stop-btn" title="Stop">⏹</button>
     </div>
   </div>
 </div>
diff --git a/renderer/js/panel/bootstrap.js b/renderer/js/panel/bootstrap.js
index 0bef1f4..2ab6240 100644
--- a/renderer/js/panel/bootstrap.js
+++ b/renderer/js/panel/bootstrap.js
@@ -73,6 +73,12 @@ export function createPanelController({
   }
 
   function bindEvents() {
+    dom.textInput.addEventListener("focus", () => {
+      if (state.isStreaming()) {
+        messaging.cancelMessage();
+      }
+    });
+
     dom.textInput.addEventListener("keydown", (event) => {
       if (event.key === "Enter" && !event.shiftKey) {
         event.preventDefault();
@@ -86,6 +92,10 @@ export function createPanelController({
     });
 
     dom.sendBtn.addEventListener("click", messaging.sendMessage);
+    const stopBtn = doc.getElementById("stop-btn");
+    if (stopBtn) {
+      stopBtn.addEventListener("click", messaging.cancelMessage);
+    }
     dom.btnPlanPrev.addEventListener("click", () => api.invoke("previous-step"));
     dom.btnPlanDone.addEventListener("click", () => api.invoke("mark-step-done"));
     dom.btnPlanSkip.addEventListener("click", () => api.invoke("skip-current-step"));
diff --git a/renderer/js/panel/messaging.js b/renderer/js/panel/messaging.js
index 851b95e..30254ac 100644
--- a/renderer/js/panel/messaging.js
+++ b/renderer/js/panel/messaging.js
@@ -7,6 +7,38 @@ export function createMessagingController({
   ui,
 }) {
   let syncQueue = Promise.resolve();
+  let currentAbortController = null;
+  let requestTimeoutId = null;
+
+  function cancelMessage() {
+    if (!state.isStreaming()) return;
+
+    if (currentAbortController) {
+      currentAbortController.abort();
+      currentAbortController = null;
+    }
+
+    if (requestTimeoutId) {
+      clearTimeout(requestTimeoutId);
+      requestTimeoutId = null;
+    }
+
+    log("ai:cancel-message invoke");
+    api.invoke("abort-message").catch(err => log("ipc:abort-message error", err));
+
+    state.setStreaming(false);
+    dom.sendBtn.classList.remove("hidden");
+    const stopBtn = doc.getElementById("stop-btn");
+    if (stopBtn) stopBtn.classList.add("hidden");
+    dom.sendBtn.disabled = false;
+    
+    ui.renderAgentState("idle");
+    ui.removeAllTypingIndicators();
+
+    if (state.getStreamingBubble()) {
+      state.clearStreamingSession();
+    }
+  }
 
   function syncSession(session) {
     syncQueue = syncQueue.then(() => syncSessionInternal(session)).catch((error) => {
@@ -93,9 +125,23 @@ export function createMessagingController({
     dom.textInput.value = "";
     dom.textInput.style.height = "auto";
     state.setStreaming(true);
+    
+    dom.sendBtn.classList.add("hidden");
+    const stopBtn = doc.getElementById("stop-btn");
+    if (stopBtn) stopBtn.classList.remove("hidden");
     dom.sendBtn.disabled = true;
+    
     ui.renderAgentState("thinking");
 
+    currentAbortController = new AbortController();
+    requestTimeoutId = window.setTimeout(() => {
+      if (state.isStreaming()) {
+        log("ai:send-message timeout 60s triggered");
+        cancelMessage();
+        ui.showToast("Request timed out", true);
+      }
+    }, 60000);
+
     let typingId = null;
     log("ai:send-message start", {
       hasImages: Boolean(images && images.length),
@@ -128,8 +174,6 @@ export function createMessagingController({
     } catch (error) {
       onAIError(error.message);
     } finally {
-      state.setStreaming(false);
-      dom.sendBtn.disabled = false;
       if (typingId !== null) {
         ui.removeTypingIndicator(typingId);
       }
@@ -151,7 +195,14 @@ export function createMessagingController({
 
   function onAIDone(parsed) {
     const result = parsed || {};
+    if (requestTimeoutId) {
+      clearTimeout(requestTimeoutId);
+      requestTimeoutId = null;
+    }
     state.setStreaming(false);
+    dom.sendBtn.classList.remove("hidden");
+    const stopBtn = doc.getElementById("stop-btn");
+    if (stopBtn) stopBtn.classList.add("hidden");
     dom.sendBtn.disabled = false;
     ui.renderAgentState("idle");
 
@@ -189,7 +240,14 @@ export function createMessagingController({
       ? { message: errorMessage, code: "unknown_error", action: "open-settings", requestId: "" }
       : (errorMessage || {});
     const safeMessage = payload.message || "Unexpected error";
+    if (requestTimeoutId) {
+      clearTimeout(requestTimeoutId);
+      requestTimeoutId = null;
+    }
     state.setStreaming(false);
+    dom.sendBtn.classList.remove("hidden");
+    const stopBtn = doc.getElementById("stop-btn");
+    if (stopBtn) stopBtn.classList.add("hidden");
     dom.sendBtn.disabled = false;
     ui.renderAgentState("idle");
     ui.removeAllTypingIndicators();
@@ -222,5 +280,6 @@ export function createMessagingController({
     onAIDone,
     onAIError,
     sendMessage,
+    cancelMessage,
   };
 }