diff --git a/schemas/hooks.schema.json b/schemas/hooks.schema.json
index d07d61d..ceb2bd9 100644
--- a/schemas/hooks.schema.json
+++ b/schemas/hooks.schema.json
@@ -25,6 +25,15 @@
               }
             }
           ]
+        },
+        "async": {
+          "type": "boolean",
+          "description": "Run hook asynchronously in background without blocking"
+        },
+        "timeout": {
+          "type": "number",
+          "minimum": 0,
+          "description": "Timeout in seconds for async hooks"
         }
       }
     },
diff --git a/scripts/ci/validate-hooks.js b/scripts/ci/validate-hooks.js
index dc3f6f4..ddc08df 100644
--- a/scripts/ci/validate-hooks.js
+++ b/scripts/ci/validate-hooks.js
@@ -24,6 +24,16 @@ function validateHookEntry(hook, label) {
     hasErrors = true;
   }
 
+  // Validate optional async and timeout fields
+  if ('async' in hook && typeof hook.async !== 'boolean') {
+    console.error(`ERROR: ${label} 'async' must be a boolean`);
+    hasErrors = true;
+  }
+  if ('timeout' in hook && (typeof hook.timeout !== 'number' || hook.timeout < 0)) {
+    console.error(`ERROR: ${label} 'timeout' must be a non-negative number`);
+    hasErrors = true;
+  }
+
   if (!hook.command || (typeof hook.command !== 'string' && !Array.isArray(hook.command))) {
     console.error(`ERROR: ${label} missing or invalid 'command' field`);
     hasErrors = true;
diff --git a/tests/hooks/hooks.test.js b/tests/hooks/hooks.test.js
index 7da7eb4..aebe0d2 100644
--- a/tests/hooks/hooks.test.js
+++ b/tests/hooks/hooks.test.js
@@ -278,6 +278,7 @@ async function runTests() {
     assert.ok(hooks.hooks.PreToolUse, 'Should have PreToolUse hooks');
     assert.ok(hooks.hooks.PostToolUse, 'Should have PostToolUse hooks');
     assert.ok(hooks.hooks.SessionStart, 'Should have SessionStart hooks');
+    assert.ok(hooks.hooks.SessionEnd, 'Should have SessionEnd hooks');
     assert.ok(hooks.hooks.Stop, 'Should have Stop hooks');
     assert.ok(hooks.hooks.PreCompact, 'Should have PreCompact hooks');
   })) passed++; else failed++;