diff --git a/frontend/src/api/client.ts b/frontend/src/api/client.ts
index 3dfeaeb..b262d9e 100644
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -186,7 +186,9 @@ export async function streamChat(
     onNotice: (msg: string) => void;
     onDone: (full: string) => void;
     onError: (msg: string) => void;
-  }
+    onAbort?: () => void;
+  },
+  signal?: AbortSignal
 ): Promise<void> {
   let res: Response;
   try {
@@ -194,8 +196,13 @@ export async function streamChat(
       method: "POST",
       headers: { "Content-Type": "application/json" },
       body: JSON.stringify(body),
+      signal,
     });
   } catch (err) {
+    if (err instanceof DOMException && err.name === "AbortError") {
+      handlers.onAbort?.();
+      return;
+    }
     const raw = err instanceof Error ? err.message : "serveur Loki injoignable";
     handlers.onError(
       /network error|failed to fetch/i.test(raw)
@@ -280,6 +287,10 @@ export async function streamChat(
     if (buffer.trim()) dispatch(buffer);
   } catch (err) {
     if (!failed) {
+      if (err instanceof DOMException && err.name === "AbortError") {
+        handlers.onAbort?.();
+        return;
+      }
       failed = true;
       const raw = err instanceof Error ? err.message : "connexion interrompue";
       handlers.onError(
diff --git a/frontend/src/components/MessageContent.tsx b/frontend/src/components/MessageContent.tsx
index e41597b..b3180a4 100644
--- a/frontend/src/components/MessageContent.tsx
+++ b/frontend/src/components/MessageContent.tsx
@@ -3,24 +3,44 @@ import ReactMarkdown, { type Components } from "react-markdown";
 import remarkGfm from "remark-gfm";
 import { CheckIcon, CopyIcon } from "./Icon";
 
-/**
- * Rendu Markdown des messages de l'agent (react-markdown + GFM).
- *
- * Les blocs de code sont affichés dans un cadre avec en-tête (langage + bouton
- * « Copier »). Les autres éléments (titres, listes, gras, tableaux, liens…)
- * sont stylés pour le thème sombre « atelier » de Loki.
- */
+function copyWithTextarea(value: string) {
+  const textarea = document.createElement("textarea");
+  textarea.value = value;
+  textarea.setAttribute("readonly", "");
+  textarea.style.position = "fixed";
+  textarea.style.left = "-9999px";
+  textarea.style.top = "0";
+  document.body.appendChild(textarea);
+  textarea.select();
+  const ok = document.execCommand("copy");
+  textarea.remove();
+  if (!ok) throw new Error("copy failed");
+}
 
 function CodeBlock({ lang, code }: { lang: string; code: string }) {
   const [copied, setCopied] = useState(false);
+  const [failed, setFailed] = useState(false);
 
   const copy = async () => {
     try {
-      await navigator.clipboard.writeText(code);
+      if (navigator.clipboard?.writeText) {
+        await navigator.clipboard.writeText(code);
+      } else {
+        copyWithTextarea(code);
+      }
       setCopied(true);
+      setFailed(false);
       setTimeout(() => setCopied(false), 1500);
     } catch {
-      // Presse-papiers indisponible (contexte non sécurisé) : on ignore.
+      try {
+        copyWithTextarea(code);
+        setCopied(true);
+        setFailed(false);
+        setTimeout(() => setCopied(false), 1500);
+      } catch {
+        setFailed(true);
+        setTimeout(() => setFailed(false), 1800);
+      }
     }
   };
 
@@ -31,11 +51,12 @@ function CodeBlock({ lang, code }: { lang: string; code: string }) {
           {lang || "code"}
         </span>
         <button
+          type="button"
           onClick={copy}
           className="flex items-center gap-1 rounded-md px-1.5 py-0.5 text-[11px] text-on-dark-2 transition-colors hover:text-white"
         >
           {copied ? <CheckIcon size={13} /> : <CopyIcon size={13} />}
-          {copied ? "Copié" : "Copier"}
+          {failed ? "Erreur" : copied ? "Copié" : "Copier"}
         </button>
       </div>
       <pre className="scr m-0 overflow-auto p-3 font-mono text-[12px] leading-relaxed text-on-dark">
@@ -46,8 +67,6 @@ function CodeBlock({ lang, code }: { lang: string; code: string }) {
 }
 
 const components: Components = {
-  // react-markdown emballe les blocs dans <pre><code> : on déballe le <pre>
-  // pour laisser notre CodeBlock (un <div>) se placer au niveau racine.
   pre: ({ children }) => <>{children}</>,
   code({ className, children }) {
     const text = String(children).replace(/\n$/, "");
diff --git a/frontend/src/panels/ChatPanel.tsx b/frontend/src/panels/ChatPanel.tsx
index 44e6841..0b66c09 100644
--- a/frontend/src/panels/ChatPanel.tsx
+++ b/frontend/src/panels/ChatPanel.tsx
@@ -24,6 +24,7 @@ export function ChatPanel() {
     approveShell,
     rejectShell,
     sessions,
+    stopStreaming,
   } = useStore();
 
   const activeTools = config
@@ -154,12 +155,14 @@ export function ChatPanel() {
                 </>
               )}
               <button
-                onClick={submit}
-                disabled={streaming || !draft.trim()}
-                className="flex h-[38px] items-center gap-1.5 border-[3px] border-line bg-card-deep px-4 text-[14px] text-white shadow-hard-accent disabled:opacity-40"
+                onClick={streaming ? stopStreaming : submit}
+                disabled={!streaming && !draft.trim()}
+                className={`flex h-[38px] items-center gap-1.5 border-[3px] border-line px-4 text-[14px] text-white shadow-hard-accent disabled:opacity-40 ${
+                  streaming ? "bg-warn" : "bg-card-deep"
+                }`}
                 style={{ borderRadius: 7 }}
               >
-                {streaming ? "…" : "ENVOYER"}
+                {streaming ? "ARRÊTER" : "ENVOYER"}
                 {!streaming && <SendIcon />}
               </button>
             </div>
diff --git a/frontend/src/store/useStore.ts b/frontend/src/store/useStore.ts
index bff8890..36826e8 100644
--- a/frontend/src/store/useStore.ts
+++ b/frontend/src/store/useStore.ts
@@ -62,8 +62,11 @@ interface LokiState {
   openSession: (id: string) => Promise<void>;
   removeSession: (id: string) => Promise<void>;
   sendMessage: (content: string) => Promise<void>;
+  stopStreaming: () => void;
 }
 
+let activeStreamController: AbortController | null = null;
+
 export const useStore = create<LokiState>((set, get) => ({
   status: null,
   models: [],
@@ -207,6 +210,22 @@ export const useStore = create<LokiState>((set, get) => ({
     await get().refreshSessions();
   },
 
+  stopStreaming: () => {
+    activeStreamController?.abort();
+    activeStreamController = null;
+    set({
+      streaming: false,
+      streamingSessionId: null,
+      streamContent: "",
+      streamThinking: "",
+      streamStatus: "",
+      streamNotice: null,
+      streamTools: [],
+      pendingShell: null,
+    });
+    void get().refreshSessions();
+  },
+
   sendMessage: async (content) => {
     if (get().streaming) return;
     content = content.trim();
@@ -264,6 +283,9 @@ export const useStore = create<LokiState>((set, get) => ({
       pendingShell: null,
     });
 
+    const controller = new AbortController();
+    activeStreamController = controller;
+
     await streamChat(
       { session_id: sid, content, model: get().selectedModel || undefined },
       {
@@ -286,6 +308,7 @@ export const useStore = create<LokiState>((set, get) => ({
         },
         onToolConfirm: (command) => set({ pendingShell: command }),
         onDone: async () => {
+          activeStreamController = null;
           // Repère un fichier HTML écrit pour l'afficher automatiquement.
           const writtenHtml = [...get().streamTools]
             .reverse()
@@ -311,6 +334,7 @@ export const useStore = create<LokiState>((set, get) => ({
           if (writtenHtml) await get().openPreview(writtenHtml.args.path as string);
         },
         onError: (msg) => {
+          activeStreamController = null;
           const errMsg: Message = {
             id: `err-${Date.now()}`,
             session_id: sid!,
@@ -333,7 +357,22 @@ export const useStore = create<LokiState>((set, get) => ({
           });
           void get().refreshSessions();
         },
-      }
+        onAbort: () => {
+          activeStreamController = null;
+          set({
+            streaming: false,
+            streamingSessionId: null,
+            streamContent: "",
+            streamThinking: "",
+            streamStatus: "",
+            streamNotice: null,
+            streamTools: [],
+            pendingShell: null,
+          });
+          void get().refreshSessions();
+        },
+      },
+      controller.signal
     );
   },
 }));