diff --git a/mateclaw-ui/src/components/workflow/StepPropertyPanel.vue b/mateclaw-ui/src/components/workflow/StepPropertyPanel.vue
index 6f6b77b8..73e58964 100644
--- a/mateclaw-ui/src/components/workflow/StepPropertyPanel.vue
+++ b/mateclaw-ui/src/components/workflow/StepPropertyPanel.vue
@@ -66,7 +66,7 @@
           @input="patch({ promptTemplate: ($event.target as HTMLTextAreaElement).value })"
           spellcheck="false"
           rows="3"
-          :placeholder="t('workflows.canvas.fields.promptPlaceholder')"
+          :placeholder="PROMPT_PLACEHOLDER"
         />
       </label>
 
@@ -319,6 +319,14 @@ const emit = defineEmits<{
 
 const { t } = useI18n()
 
+// The Pebble example shown in the textarea placeholder is the same in every
+// locale and contains literal `{{ }}`. Routing it through vue-i18n's t()
+// works but the library does a second compile pass on the returned string
+// looking for linked messages / nested placeholders, which trips on the
+// inner braces and floods the console with parse errors. Keeping it as a
+// plain const sidesteps the parser entirely.
+const PROMPT_PLACEHOLDER = 'Hello {{ inputs.payload }}'
+
 const modeType = computed(() => (props.step?.mode?.type ?? 'sequential') as string)
 
 const localizedModeLabel = computed(() => {
diff --git a/mateclaw-ui/src/i18n/index.ts b/mateclaw-ui/src/i18n/index.ts
index 02c87c76..46d5ba3f 100644
--- a/mateclaw-ui/src/i18n/index.ts
+++ b/mateclaw-ui/src/i18n/index.ts
@@ -1,4 +1,5 @@
 import { createI18n } from 'vue-i18n'
+import { compileToFunction, registerMessageCompiler } from '@intlify/core-base'
 import { ref } from 'vue'
 import { settingsApi } from '@/api'
 
@@ -9,11 +10,30 @@ const DEFAULT_LOCALE: AppLocale = 'zh-CN'
 
 export const currentLocale = ref<AppLocale>(DEFAULT_LOCALE)
 
+// Replace vue-i18n's default message compiler with a safety wrapper. The
+// default compiler throws on parse errors in production builds, which
+// caused a regression: workflow step prompts containing Pebble syntax
+// (`Hello {{ inputs.payload }}`) leaked into i18n's parser through one of
+// vue-i18n's internal lookups and aborted the property panel render.
+// Catching the throw here keeps the panel alive — the worst case is that
+// a malformed message renders as its literal text instead of the
+// interpolated form, which is the same fallback dev mode already has.
+const safeMessageCompiler = ((message: any, context: any) => {
+  try {
+    return compileToFunction(message, context)
+  } catch {
+    const literal = typeof message === 'string' ? message : String(message)
+    return () => literal
+  }
+}) as typeof compileToFunction
+registerMessageCompiler(safeMessageCompiler)
+
 export const i18n = createI18n({
   legacy: false,
   locale: DEFAULT_LOCALE,
   fallbackLocale: DEFAULT_LOCALE,
   messages: {} as Record<AppLocale, any>,
+  messageCompiler: safeMessageCompiler,
 })
 
 const loadedLocales = new Set<AppLocale>()
diff --git a/mateclaw-ui/src/i18n/locales/en-US.ts b/mateclaw-ui/src/i18n/locales/en-US.ts
index 3d55391f..eb68d153 100644
--- a/mateclaw-ui/src/i18n/locales/en-US.ts
+++ b/mateclaw-ui/src/i18n/locales/en-US.ts
@@ -2222,7 +2222,8 @@ export default {
         agentPlaceholder: 'Select digital employee',
         agentMissing: 'Current digital employee is not in the list: {name}',
         promptTemplate: 'Prompt template',
-        promptPlaceholder: 'Hello {{ inputs.payload }}',
+        // promptPlaceholder is intentionally not localized — hardcoded in
+        // StepPropertyPanel so vue-i18n's parser never sees the Pebble braces.
         outputVar: 'Output variable',
         outputVarPlaceholder: 'data',
         outputContentType: 'Output type',
diff --git a/mateclaw-ui/src/i18n/locales/zh-CN.ts b/mateclaw-ui/src/i18n/locales/zh-CN.ts
index 7018e49e..2b03cc8a 100644
--- a/mateclaw-ui/src/i18n/locales/zh-CN.ts
+++ b/mateclaw-ui/src/i18n/locales/zh-CN.ts
@@ -2234,7 +2234,8 @@ export default {
         agentPlaceholder: '选择数字员工',
         agentMissing: '当前数字员工不在列表中：{name}',
         promptTemplate: 'Prompt 模板',
-        promptPlaceholder: 'Hello {{ inputs.payload }}',
+        // promptPlaceholder is intentionally not localized — hardcoded in
+        // StepPropertyPanel so vue-i18n's parser never sees the Pebble braces.
         outputVar: '输出变量名',
         outputVarPlaceholder: 'data',
         outputContentType: '输出类型',