diff --git a/client/src/components/run/TerminalView.tsx b/client/src/components/run/TerminalView.tsx
index bb48548..f16ff27 100644
--- a/client/src/components/run/TerminalView.tsx
+++ b/client/src/components/run/TerminalView.tsx
@@ -29,18 +29,23 @@ export function TerminalView({ runId, wsBaseUrl }: TerminalViewProps) {
     fit.fit();
 
     const ws = new WebSocket(`${wsBaseUrl}/ws-pty/${encodeURIComponent(runId)}`);
+    // Server sends PTY bytes as binary frames — default binaryType ("blob")
+    // would hand onmessage a Blob that the string checks below never match,
+    // silently dropping all terminal output. "arraybuffer" keeps it sync.
+    ws.binaryType = "arraybuffer";
 
+    const decoder = new TextDecoder();
     ws.onopen = () => {
       ws.send(JSON.stringify({ type: "resize", cols: term.cols, rows: term.rows }));
     };
     ws.onmessage = (event) => {
-      if (typeof event.data === "string") {
-        // Binary PTY output arrives as text here too (the browser WS API
-        // decodes non-Blob/ArrayBuffer frames as strings) — a JSON control
-        // frame is the only thing that starts with `{"type"`.
-        if (event.data.startsWith('{"type"')) {
+      const isArrayBuffer = Object.prototype.toString.call(event.data) === "[object ArrayBuffer]";
+      const data = isArrayBuffer ? decoder.decode(event.data as ArrayBuffer) : event.data;
+      if (typeof data === "string") {
+        // A JSON control frame is the only thing that starts with `{"type"`.
+        if (data.startsWith('{"type"')) {
           try {
-            const msg = JSON.parse(event.data);
+            const msg = JSON.parse(data);
             if (msg.type === "exit") {
               term.write(`\r\n[session ended, exit code ${msg.code}]\r\n`);
             }
@@ -49,7 +54,7 @@ export function TerminalView({ runId, wsBaseUrl }: TerminalViewProps) {
             /* not JSON — fall through and render as PTY output */
           }
         }
-        term.write(event.data);
+        term.write(data);
       }
     };
 
diff --git a/client/src/components/run/__tests__/TerminalView.test.tsx b/client/src/components/run/__tests__/TerminalView.test.tsx
index 2cf1c76..dfda206 100644
--- a/client/src/components/run/__tests__/TerminalView.test.tsx
+++ b/client/src/components/run/__tests__/TerminalView.test.tsx
@@ -75,6 +75,15 @@ describe("TerminalView", () => {
     expect(writeMock).toHaveBeenCalledWith("hello");
   });
 
+  it("decodes binary ArrayBuffer frames (server sends PTY output as binary)", () => {
+    render(<TerminalView runId="ccam-lane-1" wsBaseUrl="ws://localhost:4820" />);
+    const ws = MockWebSocket.instances[0]!;
+    ws.onopen?.();
+    const bytes = new TextEncoder().encode("hello-binary").buffer;
+    ws.onmessage?.({ data: bytes });
+    expect(writeMock).toHaveBeenCalledWith("hello-binary");
+  });
+
   it("forwards terminal keystrokes as outgoing WS sends", () => {
     render(<TerminalView runId="ccam-lane-1" wsBaseUrl="ws://localhost:4820" />);
     const ws = MockWebSocket.instances[0]!;