diff --git a/docs/changelog/2026-06-11-servers-search-null-fix.md b/docs/changelog/2026-06-11-servers-search-null-fix.md
new file mode 100644
index 00000000..9b0452cd
--- /dev/null
+++ b/docs/changelog/2026-06-11-servers-search-null-fix.md
@@ -0,0 +1,32 @@
+# Changelog — 修复 Servers 搜索 combobox null 导致列表加载失败
+
+**日期**：2026-06-11
+
+## 摘要
+
+`v-combobox` 清空时 `search` 为 `null`，`trim()` 抛错触发「加载服务器列表失败」；同时 `{ query: null }` 使 422 响应因 `ctx` 含 `ValueError` 无法 JSON 序列化而变成 500。
+
+## 动机
+
+生产日志：`PUT /api/servers/search-history` 输入 `query: null` → 422 处理崩溃；前端 `search.value.trim()` 在 null 时异常。
+
+## 涉及文件
+
+- `frontend/src/composables/useServerPagination.ts`
+- `frontend/src/composables/useServerSearchHistory.ts`
+- `frontend/src/pages/ServersPage.vue`
+- `server/utils/validation_errors_zh.py`
+- `tests/test_validation_errors_zh.py`
+
+## 迁移 / 重启
+
+- 需部署前后端；无 DB 变更
+
+## 验证
+
+```bash
+pytest tests/test_validation_errors_zh.py tests/test_server_search_history.py -q
+cd frontend && npm run type-check
+```
+
+Servers 页清空搜索框 → 列表正常加载，无错误 toast。
diff --git a/frontend/src/composables/useServerPagination.ts b/frontend/src/composables/useServerPagination.ts
index 7576d5f9..e1faf8b4 100644
--- a/frontend/src/composables/useServerPagination.ts
+++ b/frontend/src/composables/useServerPagination.ts
@@ -30,7 +30,7 @@ export function useServerPagination(options?: UseServerPaginationOptions) {
   const sortBy = ref<TableSortItem[]>([])
 
   function listQueryParams(): Record<string, unknown> {
-    const q = search.value.trim()
+    const q = String(search.value ?? '').trim()
     // 有搜索词时全局检索：忽略分类/在线/路径分区，避免刚添加的机器搜不到
     const applyPathFilter = targetPathUnset !== undefined && !q
     return {
diff --git a/frontend/src/composables/useServerSearchHistory.ts b/frontend/src/composables/useServerSearchHistory.ts
index 4a093d6c..40a95cea 100644
--- a/frontend/src/composables/useServerSearchHistory.ts
+++ b/frontend/src/composables/useServerSearchHistory.ts
@@ -74,9 +74,12 @@ export function useServerSearchHistory() {
     }
   }
 
-  async function record(query: string) {
+  async function record(query: string | null | undefined) {
+    const normalized = String(query ?? '').trim()
     try {
-      const res = await http.put<ServerSearchHistoryResponse>('/servers/search-history', { query })
+      const res = await http.put<ServerSearchHistoryResponse>('/servers/search-history', {
+        query: normalized,
+      })
       items.value = res.history || []
     } catch {
       // non-blocking
diff --git a/frontend/src/pages/ServersPage.vue b/frontend/src/pages/ServersPage.vue
index e6959a2e..3895e8bc 100644
--- a/frontend/src/pages/ServersPage.vue
+++ b/frontend/src/pages/ServersPage.vue
@@ -762,6 +762,7 @@ const { items: serverSearchHistory, record: recordServerSearch, bootstrap: boots
 
 let searchDebounceTimer: ReturnType<typeof setTimeout>
 function onSearch() {
+  if (search.value == null) search.value = ''
   clearTimeout(searchDebounceTimer)
   searchDebounceTimer = setTimeout(() => {
     void recordServerSearch(search.value)
@@ -1046,7 +1047,7 @@ watch(search, () => {
 watch(
   () => [search.value, total.value, unsetPathTotal.value, pendingServers.value.length, loading.value] as const,
   ([q, mainTotal, unsetTotal, pendingCount, isLoading]) => {
-    if (!q.trim() || isLoading) return
+    if (!String(q ?? '').trim() || isLoading) return
     if (mainTotal > 0 || unsetTotal > 0) return
     if (pendingCount <= 0) return
     void nextTick(() => {
@@ -1102,7 +1103,7 @@ function showFailureDialog(errors: PollErrorItem[], message?: string) {
 async function loadPendingServers(silent = false) {
   if (!silent) pendingLoading.value = true
   try {
-    const q = search.value.trim()
+    const q = String(search.value ?? '').trim()
     const res = await http.get<{ items: PendingServerItem[]; total: number }>(
       '/servers/pending',
       q ? { search: q } : undefined,
diff --git a/server/utils/validation_errors_zh.py b/server/utils/validation_errors_zh.py
index b3d7dc53..ff99583e 100644
--- a/server/utils/validation_errors_zh.py
+++ b/server/utils/validation_errors_zh.py
@@ -133,11 +133,12 @@ def translate_validation_errors(errors: list[dict[str, Any]]) -> list[dict[str,
     """Clone Pydantic error dicts with translated ``msg`` and ``loc_zh``."""
     translated: list[dict[str, Any]] = []
     for err in errors:
-        item = dict(err)
+        ctx = err.get("ctx") if isinstance(err.get("ctx"), dict) else None
+        item = {k: v for k, v in err.items() if k != "ctx"}
         item["msg"] = translate_validation_msg(
             str(err.get("msg", "")),
             str(err.get("type", "")),
-            err.get("ctx") if isinstance(err.get("ctx"), dict) else None,
+            ctx,
         )
         item["loc_zh"] = translate_loc_zh(err.get("loc"))
         translated.append(item)
diff --git a/tests/test_validation_errors_zh.py b/tests/test_validation_errors_zh.py
index a62e4309..9fd8736f 100644
--- a/tests/test_validation_errors_zh.py
+++ b/tests/test_validation_errors_zh.py
@@ -62,6 +62,21 @@ def test_translate_list_too_long_ctx():
     assert msg == "最多 50 项，当前 101 项"
 
 
+def test_translate_strips_non_json_ctx():
+    """Pydantic value_error ctx may contain Exception objects — must not leak into JSON."""
+    out = translate_validation_errors([
+        {
+            "type": "value_error",
+            "loc": ("body",),
+            "msg": "Value error, query 或 history 至少提供一个",
+            "input": {"query": None},
+            "ctx": {"error": ValueError("query 或 history 至少提供一个")},
+        },
+    ])
+    assert "ctx" not in out[0]
+    assert out[0]["msg"] == "query 或 history 至少提供一个"
+
+
 def test_batch_agent_accepts_101_ids():
     from server.api.schemas import BatchAgentAction