diff --git a/skills/dispatch-webhook/handler.ts b/skills/dispatch-webhook/handler.ts
index b2367c3..2712ea9 100644
--- a/skills/dispatch-webhook/handler.ts
+++ b/skills/dispatch-webhook/handler.ts
@@ -12,6 +12,56 @@ interface DispatchInput {
   retries?: number;
 }
 
+const ALLOWED_TARGETS = new Set<DispatchInput['target']>(['vps-a', 'vps-b']);
+
+function clampInt(value: unknown, min: number, max: number, fallback: number): number {
+  const n = Number(value);
+  if (!Number.isFinite(n)) return fallback;
+  return Math.min(max, Math.max(min, Math.floor(n)));
+}
+
+function sanitizeTaskId(taskId: unknown): string {
+  if (taskId == null) return '';
+  return String(taskId).replace(/[\r\n]/g, '').slice(0, 128);
+}
+
+function validateInput(raw: any): DispatchInput {
+  const input = raw as Partial<DispatchInput>;
+
+  if (!input || typeof input !== 'object') {
+    throw new Error('dispatch-webhook 輸入格式錯誤：必須提供 input 物件');
+  }
+
+  if (!input.target || !ALLOWED_TARGETS.has(input.target as DispatchInput['target'])) {
+    throw new Error('dispatch-webhook 參數錯誤：target 必須是 vps-a 或 vps-b');
+  }
+
+  if (!input.webhookUrl || typeof input.webhookUrl !== 'string') {
+    throw new Error(`${input.target.toUpperCase()} Webhook URL 未設定。請在環境變數設定 VPS_A_WEBHOOK_URL 或 VPS_B_WEBHOOK_URL`);
+  }
+
+  let parsedUrl: URL;
+  try {
+    parsedUrl = new URL(input.webhookUrl);
+  } catch {
+    throw new Error('Webhook URL 格式錯誤，請提供有效的 http/https URL');
+  }
+
+  if (!['http:', 'https:'].includes(parsedUrl.protocol)) {
+    throw new Error('Webhook URL 協定不支援，僅允許 http 或 https');
+  }
+
+  if (!input.webhookToken || typeof input.webhookToken !== 'string') {
+    throw new Error(`${input.target.toUpperCase()} Webhook Token 未設定`);
+  }
+
+  if (!input.payload || typeof input.payload !== 'object' || Array.isArray(input.payload)) {
+    throw new Error('dispatch-webhook 參數錯誤：payload 必須是 JSON 物件');
+  }
+
+  return input as DispatchInput;
+}
+
 async function fetchWithTimeout(url: string, options: RequestInit, timeoutMs: number): Promise<Response> {
   const controller = new AbortController();
   const timer = setTimeout(() => controller.abort(), timeoutMs);
@@ -23,17 +73,11 @@ async function fetchWithTimeout(url: string, options: RequestInit, timeoutMs: nu
 }
 
 export async function handler(ctx: any) {
-  const input: DispatchInput = ctx.input || ctx.params;
+  const input = validateInput(ctx.input || ctx.params);
 
-  if (!input.webhookUrl) {
-    throw new Error(`${input.target.toUpperCase()} Webhook URL 未設定。請在環境變數設定 VPS_A_WEBHOOK_URL 或 VPS_B_WEBHOOK_URL`);
-  }
-  if (!input.webhookToken) {
-    throw new Error(`${input.target.toUpperCase()} Webhook Token 未設定`);
-  }
-
-  const timeoutMs = input.timeoutMs ?? 30000;
-  const maxRetries = input.retries ?? 3;
+  const timeoutMs = clampInt(input.timeoutMs, 1000, 120000, 30000);
+  const maxRetries = clampInt(input.retries, 1, 5, 3);
+  const taskIdHeader = sanitizeTaskId(input.payload.task_id);
   let lastError: Error | null = null;
 
   for (let attempt = 1; attempt <= maxRetries; attempt++) {
@@ -46,7 +90,7 @@ export async function handler(ctx: any) {
             'Content-Type': 'application/json',
             'Authorization': `Bearer ${input.webhookToken}`,
             'X-OpenClaw-Version': '1.0',
-            'X-OpenClaw-Task-Id': String(input.payload.task_id || ''),
+            'X-OpenClaw-Task-Id': taskIdHeader,
           },
           body: JSON.stringify(input.payload),
         },
@@ -72,8 +116,8 @@ export async function handler(ctx: any) {
       };
 
     } catch (err: any) {
-      lastError = err;
-      if (err.message?.includes('401') || err.message?.includes('Token')) {
+      lastError = err instanceof Error ? err : new Error(String(err));
+      if (lastError.message.includes('401') || lastError.message.includes('Token')) {
         break; // 認證錯誤不重試
       }
       if (attempt < maxRetries) {