1 files changed, 105 insertions, 0 deletions
diff --git a/packages/cli/src/ui/utils/kittyProtocolDetector.ts b/packages/cli/src/ui/utils/kittyProtocolDetector.ts
new file mode 100644
index 00000000..5d77943a
--- /dev/null
+++ b/packages/cli/src/ui/utils/kittyProtocolDetector.ts
@@ -0,0 +1,105 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+let detectionComplete = false;
+let protocolSupported = false;
+let protocolEnabled = false;
+
+/**
+ * Detects Kitty keyboard protocol support.
+ * Definitive document about this protocol lives at https://sw.kovidgoyal.net/kitty/keyboard-protocol/
+ * This function should be called once at app startup.
+ */
+export async function detectAndEnableKittyProtocol(): Promise<boolean> {
+  if (detectionComplete) {
+    return protocolSupported;
+  }
+
+  return new Promise((resolve) => {
+    if (!process.stdin.isTTY || !process.stdout.isTTY) {
+      detectionComplete = true;
+      resolve(false);
+      return;
+    }
+
+    const originalRawMode = process.stdin.isRaw;
+    if (!originalRawMode) {
+      process.stdin.setRawMode(true);
+    }
+
+    let responseBuffer = '';
+    let progressiveEnhancementReceived = false;
+    let checkFinished = false;
+
+    const handleData = (data: Buffer) => {
+      responseBuffer += data.toString();
+
+      // Check for progressive enhancement response (CSI ? <flags> u)
+      if (responseBuffer.includes('\x1b[?') && responseBuffer.includes('u')) {
+        progressiveEnhancementReceived = true;
+      }
+
+      // Check for device attributes response (CSI ? <attrs> c)
+      if (responseBuffer.includes('\x1b[?') && responseBuffer.includes('c')) {
+        if (!checkFinished) {
+          checkFinished = true;
+          process.stdin.removeListener('data', handleData);
+
+          if (!originalRawMode) {
+            process.stdin.setRawMode(false);
+          }
+
+          if (progressiveEnhancementReceived) {
+            // Enable the protocol
+            process.stdout.write('\x1b[>1u');
+            protocolSupported = true;
+            protocolEnabled = true;
+
+            // Set up cleanup on exit
+            process.on('exit', disableProtocol);
+            process.on('SIGTERM', disableProtocol);
+          }
+
+          detectionComplete = true;
+          resolve(protocolSupported);
+        }
+      }
+    };
+
+    process.stdin.on('data', handleData);
+
+    // Send queries
+    process.stdout.write('\x1b[?u'); // Query progressive enhancement
+    process.stdout.write('\x1b[c'); // Query device attributes
+
+    // Timeout after 50ms
+    setTimeout(() => {
+      if (!checkFinished) {
+        process.stdin.removeListener('data', handleData);
+        if (!originalRawMode) {
+          process.stdin.setRawMode(false);
+        }
+        detectionComplete = true;
+        resolve(false);
+      }
+    }, 50);
+  });
+}
+
+function disableProtocol() {
+  if (protocolEnabled) {
+    process.stdout.write('\x1b[<u');
+    protocolEnabled = false;
+  }
+}
+
+export function isKittyProtocolEnabled(): boolean {
+  return protocolEnabled;
+}
+
+export function isKittyProtocolSupported(): boolean {
+  return protocolSupported;
+}