diff --git a/docs-site/src/content/docs/ja/reference/adapters.md b/docs-site/src/content/docs/ja/reference/adapters.md
index c71df875e..ea97ddbcf 100644
--- a/docs-site/src/content/docs/ja/reference/adapters.md
+++ b/docs-site/src/content/docs/ja/reference/adapters.md
@@ -45,7 +45,7 @@ interface ProviderAdapter {
 ## `anthropic`
 
 **対象:** Anthropic **Messages**（`/v1/messages`）。
-**認証:** `key`（`x-api-key`）または `oauth`（Bearer + `anthropic-beta`、Claude Pro/Max 用）。
+**認証:** `key`（デフォルトは `x-api-key`、または `apiKeyTransport: "bearer"` による `Authorization: Bearer`）または `oauth`（Bearer + `anthropic-beta`、Claude Pro/Max 用）。
 
 - メッセージを Anthropic content block（text、base64 image、`tool_use`、`thinking`）に変換します。
 - **Extended thinking の計算:** Anthropic は `max_tokens > thinking.budget_tokens` を要求します。
diff --git a/docs-site/src/content/docs/ja/reference/configuration.md b/docs-site/src/content/docs/ja/reference/configuration.md
index e9a42e87d..5443729e6 100644
--- a/docs-site/src/content/docs/ja/reference/configuration.md
+++ b/docs-site/src/content/docs/ja/reference/configuration.md
@@ -136,6 +136,7 @@ token の代わりに使えます。すべての候補は timing side channel 
 | `responsesPath?` | `string` | `key` 認証の `openai-responses` リクエストに使う任意の相対 resource path。`/` で始め、URL scheme、query、fragment を含めてはいけません。省略時は従来の `/v1/responses` URL 構築を維持します。 |
 | `disabled?` | `boolean` | 設定はディスクに残すがルーティングとモデル/カタログ一覧から除外します。 |
 | `apiKey?` | `string` | API キーまたはリクエスト時に解釈する `${ENV_VAR}` / `$ENV_VAR` 参照。 |
+| `apiKeyTransport?` | `"x-api-key" \| "bearer"` | Anthropic API キーのヘッダー方式。デフォルトはネイティブの `x-api-key` です。`Authorization: Bearer <key>` が必要な互換 gateway では `"bearer"` を設定します。key 認証の `anthropic` プロバイダーでのみ有効です。 |
 | `apiKeyPool?` | `ApiKeyPoolEntry[]` | 複数キーを納める pool。`apiKey` はアクティブ項目を反映します。各項目には `id`、`key`、選択 `label`、選択数値 `addedAt` があります。 |
 | `defaultModel?` | `string` | 明示的なモデルなしでこのプロバイダーを選んだときに使うモデル。 |
 | `models?` | `string[]` | seed/fallback モデル一覧。`liveModels` が `false` ならここにあるモデルだけが発見されます。 |
diff --git a/docs-site/src/content/docs/ko/reference/adapters.md b/docs-site/src/content/docs/ko/reference/adapters.md
index 9610162ae..ddfe86864 100644
--- a/docs-site/src/content/docs/ko/reference/adapters.md
+++ b/docs-site/src/content/docs/ko/reference/adapters.md
@@ -54,7 +54,7 @@ interface ProviderAdapter {
 ## `anthropic`
 
 **대상:** Anthropic **Messages**(`/v1/messages`).
-**인증:** `key`(`x-api-key`) 또는 `oauth`(Bearer + `anthropic-beta`, Claude Pro/Max용).
+**인증:** `key`(기본 `x-api-key`, 또는 `apiKeyTransport: "bearer"` 설정 시 `Authorization: Bearer`) 또는 `oauth`(Bearer + `anthropic-beta`, Claude Pro/Max용).
 
 - 메시지를 Anthropic content block(text, base64 image, `tool_use`, `thinking`)으로 변환합니다.
 - **Extended thinking 계산:** Anthropic은 `max_tokens > thinking.budget_tokens`를 요구합니다.
diff --git a/docs-site/src/content/docs/ko/reference/configuration.md b/docs-site/src/content/docs/ko/reference/configuration.md
index f56e6288d..80f9649f3 100644
--- a/docs-site/src/content/docs/ko/reference/configuration.md
+++ b/docs-site/src/content/docs/ko/reference/configuration.md
@@ -139,6 +139,7 @@ token 대신 쓸 수 있습니다. 모든 후보는 timing side channel을 막
 | `responsesPath?` | `string` | `key` 인증 `openai-responses` 요청에 사용할 선택적 상대 resource path. `/`로 시작해야 하며 URL scheme, query, fragment를 포함할 수 없습니다. 생략하면 기존 `/v1/responses` URL 구성을 유지합니다. |
 | `disabled?` | `boolean` | 설정은 디스크에 남기되 라우팅과 모델/카탈로그 목록에서 제외합니다. |
 | `apiKey?` | `string` | API 키 또는 요청 시점에 해석할 `${ENV_VAR}` / `$ENV_VAR` 참조. |
+| `apiKeyTransport?` | `"x-api-key" \| "bearer"` | Anthropic API 키 헤더 방식입니다. 기본값은 네이티브 `x-api-key`이며, `Authorization: Bearer <key>`를 요구하는 호환 gateway에는 `"bearer"`를 설정합니다. key 인증 `anthropic` 프로바이더에서만 유효합니다. |
 | `apiKeyPool?` | `ApiKeyPoolEntry[]` | 여러 키를 담는 pool. `apiKey`는 활성 항목을 반영합니다. 각 항목에는 `id`, `key`, 선택 `label`, 선택 숫자 `addedAt`이 있습니다. |
 | `defaultModel?` | `string` | 명시적인 모델 없이 이 프로바이더를 선택했을 때 쓸 모델. |
 | `models?` | `string[]` | seed/fallback 모델 목록. `liveModels`가 `false`이면 여기 있는 모델만 발견됩니다. |
diff --git a/docs-site/src/content/docs/reference/adapters.md b/docs-site/src/content/docs/reference/adapters.md
index e2ab3ebee..25cd3b962 100644
--- a/docs-site/src/content/docs/reference/adapters.md
+++ b/docs-site/src/content/docs/reference/adapters.md
@@ -54,7 +54,7 @@ streams the response back **untranslated**.
 ## `anthropic`
 
 **Targets:** Anthropic **Messages** (`/v1/messages`).
-**Auth:** `key` (`x-api-key`) or `oauth` (Bearer + `anthropic-beta`, for Claude Pro/Max).
+**Auth:** `key` (`x-api-key` by default, or `Authorization: Bearer` with `apiKeyTransport: "bearer"`) or `oauth` (Bearer + `anthropic-beta`, for Claude Pro/Max).
 
 - Converts messages to Anthropic content blocks (text, base64 image, `tool_use`, `thinking`).
 - **Extended thinking math:** Anthropic requires `max_tokens > thinking.budget_tokens`. The adapter
diff --git a/docs-site/src/content/docs/reference/configuration.md b/docs-site/src/content/docs/reference/configuration.md
index ee28eb270..a704f12a1 100644
--- a/docs-site/src/content/docs/reference/configuration.md
+++ b/docs-site/src/content/docs/reference/configuration.md
@@ -241,6 +241,7 @@ or bind the forward explicitly to loopback (`ssh -L 127.0.0.1:20100:localhost:10
 | `responsesPath?` | `string` | Optional relative resource path for key-auth `openai-responses` requests. It must start with `/` and contain no URL scheme, query, or fragment. When omitted, the adapter keeps its legacy `/v1/responses` URL construction. |
 | `disabled?` | `boolean` | Keep the provider on disk but exclude it from routing and model/catalog listings. |
 | `apiKey?` | `string` | API key, or an `${ENV_VAR}` / `$ENV_VAR` reference resolved at request time. |
+| `apiKeyTransport?` | `"x-api-key" \| "bearer"` | Anthropic API-key header style. Defaults to native `x-api-key`; set `"bearer"` for compatible gateways that require `Authorization: Bearer <key>`. Valid only for key-auth `anthropic` providers. |
 | `apiKeyPool?` | `ApiKeyPoolEntry[]` | Multi-key pool. `apiKey` mirrors the active entry; each item has `id`, `key`, optional `label`, and optional numeric `addedAt`. |
 | `defaultModel?` | `string` | Model used when this provider is selected without an explicit model. |
 | `models?` | `string[]` | Seed/fallback model list. When `liveModels` is `false`, these are the only discovered models. |
diff --git a/docs-site/src/content/docs/ru/reference/adapters.md b/docs-site/src/content/docs/ru/reference/adapters.md
index fac4fc6cf..80c7ae647 100644
--- a/docs-site/src/content/docs/ru/reference/adapters.md
+++ b/docs-site/src/content/docs/ru/reference/adapters.md
@@ -57,7 +57,7 @@ interface ProviderAdapter {
 ## `anthropic`
 
 **Назначение:** Anthropic **Messages** (`/v1/messages`).
-**Аутентификация:** `key` (`x-api-key`) или `oauth` (Bearer + `anthropic-beta`, для Claude Pro/Max).
+**Аутентификация:** `key` (по умолчанию `x-api-key`, либо `Authorization: Bearer` при `apiKeyTransport: "bearer"`) или `oauth` (Bearer + `anthropic-beta`, для Claude Pro/Max).
 
 - Преобразует сообщения в блоки контента Anthropic (text, base64 image, `tool_use`, `thinking`).
 - **Арифметика extended thinking:** Anthropic требует `max_tokens > thinking.budget_tokens`.
diff --git a/docs-site/src/content/docs/ru/reference/configuration.md b/docs-site/src/content/docs/ru/reference/configuration.md
index 4d426322f..a3101a9d7 100644
--- a/docs-site/src/content/docs/ru/reference/configuration.md
+++ b/docs-site/src/content/docs/ru/reference/configuration.md
@@ -158,6 +158,7 @@ x-opencodex-api-key: your-secret-token
 | `responsesPath?` | `string` | Необязательный относительный путь ресурса для запросов `openai-responses` с аутентификацией `key`. Должен начинаться с `/` и не содержать схему URL, query или fragment. Если поле опущено, сохраняется прежнее построение URL `/v1/responses`. |
 | `disabled?` | `boolean` | Провайдер остаётся на диске, но исключается из маршрутизации и списков моделей/каталога. |
 | `apiKey?` | `string` | API-ключ или ссылка `${ENV_VAR}` / `$ENV_VAR`, разрешаемая в момент запроса. |
+| `apiKeyTransport?` | `"x-api-key" \| "bearer"` | Способ передачи API-ключа Anthropic. По умолчанию используется нативный `x-api-key`; для совместимых gateway, требующих `Authorization: Bearer <key>`, задайте `"bearer"`. Допустимо только для `anthropic` provider с key-аутентификацией. |
 | `apiKeyPool?` | `ApiKeyPoolEntry[]` | Пул из нескольких ключей. `apiKey` отражает активную запись; каждый элемент содержит `id`, `key`, необязательный `label` и необязательное числовое `addedAt`. |
 | `defaultModel?` | `string` | Модель, используемая при выборе этого провайдера без явной модели. |
 | `models?` | `string[]` | Список seed/fallback-моделей. Когда `liveModels` равен `false`, обнаруживаются только эти модели. |
diff --git a/docs-site/src/content/docs/zh-cn/reference/adapters.md b/docs-site/src/content/docs/zh-cn/reference/adapters.md
index 6b52365cf..6a3d89a98 100644
--- a/docs-site/src/content/docs/zh-cn/reference/adapters.md
+++ b/docs-site/src/content/docs/zh-cn/reference/adapters.md
@@ -52,7 +52,7 @@ interface ProviderAdapter {
 ## `anthropic`
 
 **目标：** Anthropic **Messages**（`/v1/messages`）。
-**认证：** `key`（`x-api-key`）或 `oauth`（Bearer + `anthropic-beta`，用于 Claude Pro/Max）。
+**认证：** `key`（默认 `x-api-key`，或设置 `apiKeyTransport: "bearer"` 后使用 `Authorization: Bearer`）或 `oauth`（Bearer + `anthropic-beta`，用于 Claude Pro/Max）。
 
 - 把消息转换成 Anthropic content block（text、base64 image、`tool_use`、`thinking`）。
 - **Extended thinking 计算：** Anthropic 要求 `max_tokens > thinking.budget_tokens`。adapter 把
diff --git a/docs-site/src/content/docs/zh-cn/reference/configuration.md b/docs-site/src/content/docs/zh-cn/reference/configuration.md
index f41c59aea..fe4b47352 100644
--- a/docs-site/src/content/docs/zh-cn/reference/configuration.md
+++ b/docs-site/src/content/docs/zh-cn/reference/configuration.md
@@ -131,6 +131,7 @@ x-opencodex-api-key: your-secret-token
 | `responsesPath?` | `string` | `key` 认证的 `openai-responses` 请求可选相对 resource path。必须以 `/` 开头，且不得包含 URL scheme、query 或 fragment。省略时保留原有的 `/v1/responses` URL 构造。 |
 | `disabled?` | `boolean` | 配置保留在磁盘上，但从路由和模型/目录列表排除。 |
 | `apiKey?` | `string` | API key，或在请求时解析的 `${ENV_VAR}` / `$ENV_VAR` 引用。 |
+| `apiKeyTransport?` | `"x-api-key" \| "bearer"` | Anthropic API key 的请求头方式。默认使用原生 `x-api-key`；兼容 gateway 要求 `Authorization: Bearer <key>` 时设为 `"bearer"`。仅适用于使用 key 认证的 `anthropic` provider。 |
 | `apiKeyPool?` | `ApiKeyPoolEntry[]` | 多 key pool。`apiKey` 映射当前活动条目；每项包含 `id`、`key`、可选 `label` 和可选数字 `addedAt`。 |
 | `defaultModel?` | `string` | 选中该 provider 但未指定明确模型时使用的模型。 |
 | `models?` | `string[]` | seed/fallback 模型列表。`liveModels` 为 `false` 时，只会发现这些模型。 |
diff --git a/gui/src/components/AddProviderModal.tsx b/gui/src/components/AddProviderModal.tsx
index a17753fa4..333971bbb 100644
--- a/gui/src/components/AddProviderModal.tsx
+++ b/gui/src/components/AddProviderModal.tsx
@@ -144,6 +144,7 @@ export default function AddProviderModal({
           : p.baseUrl,
         authMode: p.auth,
         apiKey: "",
+        apiKeyTransport: undefined,
         defaultModel: p.defaultModel ?? "",
         allowPrivateNetwork: false,
       },
diff --git a/gui/src/components/add-provider-form-pane.tsx b/gui/src/components/add-provider-form-pane.tsx
index 89a3fbd8a..78cba31d3 100644
--- a/gui/src/components/add-provider-form-pane.tsx
+++ b/gui/src/components/add-provider-form-pane.tsx
@@ -143,6 +143,18 @@ export function AddProviderFormPane({
           <AddProviderField label={t("modal.apiKey")}>
             <input className="input" type="password" value={form.apiKey} onChange={e => onFormChange({ ...form, apiKey: e.target.value })} placeholder={t("modal.apiKeyPlaceholder")} />
           </AddProviderField>
+          {form.adapter === "anthropic" && form.authMode === "key" && (
+            <AddProviderField label={t("modal.apiKeyTransport")}>
+              <select
+                className="input"
+                value={form.apiKeyTransport ?? "x-api-key"}
+                onChange={e => onFormChange({ ...form, apiKeyTransport: e.target.value === "bearer" ? "bearer" : undefined })}
+              >
+                <option value="x-api-key">{t("modal.apiKeyTransportNative")}</option>
+                <option value="bearer">{t("modal.apiKeyTransportBearer")}</option>
+              </select>
+            </AddProviderField>
+          )}
         </>
       )}
       {!isReservedForward && <AddProviderField label={t("modal.defaultModel")}>
diff --git a/gui/src/components/add-provider-modal-reducer.ts b/gui/src/components/add-provider-modal-reducer.ts
index db9775d62..97ee7cb17 100644
--- a/gui/src/components/add-provider-modal-reducer.ts
+++ b/gui/src/components/add-provider-modal-reducer.ts
@@ -56,7 +56,7 @@ export function createInitialAddProviderState(
   return {
     preset: initialCustom ? customPreset : null,
     form: initialCustom
-      ? { name: "", adapter: "openai-chat", baseUrl: "", authMode: "key", apiKey: "", defaultModel: "", allowPrivateNetwork: false }
+      ? { name: "", adapter: "openai-chat", baseUrl: "", authMode: "key", apiKey: "", apiKeyTransport: undefined, defaultModel: "", allowPrivateNetwork: false }
       : null,
     saving: false,
     error: "",
diff --git a/gui/src/components/provider-workspace/ProviderSettings.tsx b/gui/src/components/provider-workspace/ProviderSettings.tsx
index e88047366..c43776467 100644
--- a/gui/src/components/provider-workspace/ProviderSettings.tsx
+++ b/gui/src/components/provider-workspace/ProviderSettings.tsx
@@ -40,6 +40,7 @@ export default function ProviderSettings({
   const [baseUrl, setBaseUrl] = useState(item.baseUrl);
   const [defaultModel, setDefaultModel] = useState(item.defaultModel ?? "");
   const [authMode, setAuthMode] = useState(initialAuth);
+  const [apiKeyTransport, setApiKeyTransport] = useState(item.apiKeyTransport ?? "x-api-key");
   const [note, setNote] = useState(item.note ?? "");
   const [allowPrivateNetwork, setAllowPrivateNetwork] = useState(item.allowPrivateNetwork ?? false);
   const [liveModels, setLiveModels] = useState(item.liveModels !== false);
@@ -55,12 +56,13 @@ export default function ProviderSettings({
     setBaseUrl(item.baseUrl);
     setDefaultModel(item.defaultModel ?? "");
     setAuthMode(String(item.authMode ?? (item.keyOptional ? "local" : "key")));
+    setApiKeyTransport(item.apiKeyTransport ?? "x-api-key");
     setNote(item.note ?? "");
     setAllowPrivateNetwork(item.allowPrivateNetwork ?? false);
     setLiveModels(item.liveModels !== false);
     setMsg(null);
     queueMicrotask(() => setEndpointChoice(matchChoiceId(baseUrlChoices, item.baseUrl)));
-  }, [item.adapter, item.baseUrl, item.defaultModel, item.authMode, item.keyOptional, item.note, item.allowPrivateNetwork, item.liveModels, baseUrlChoices]);
+  }, [item.adapter, item.baseUrl, item.defaultModel, item.authMode, item.apiKeyTransport, item.keyOptional, item.note, item.allowPrivateNetwork, item.liveModels, baseUrlChoices]);
   /* eslint-enable react-hooks/set-state-in-effect */
 
   useEffect(() => {
@@ -97,6 +99,7 @@ export default function ProviderSettings({
     || baseUrl.trim() !== item.baseUrl
     || defaultModel.trim() !== (item.defaultModel ?? "")
     || authMode !== String(item.authMode ?? (item.keyOptional ? "local" : "key"))
+    || (adapter.trim() === "anthropic" && authMode === "key" && apiKeyTransport !== (item.apiKeyTransport ?? "x-api-key"))
     || note.trim() !== (item.note ?? "")
     || allowPrivateNetwork !== (item.allowPrivateNetwork ?? false)
     || liveModels !== (item.liveModels !== false);
@@ -118,6 +121,7 @@ export default function ProviderSettings({
 
   const isPreset = isCatalogProviderId(item.name);
   const hasEndpointPicker = choicesStatus === "ready" && !!(baseUrlChoices && baseUrlChoices.length > 0);
+  const supportsApiKeyTransport = adapter.trim() === "anthropic" && authMode === "key";
   // Lock plain baseUrl for presets while loading or when there is no picker.
   // On fetch error, keep it editable so allowBaseUrlOverride providers are not trapped.
   const plainBaseUrlLocked = isPreset && choicesStatus !== "error";
@@ -132,6 +136,8 @@ export default function ProviderSettings({
     setMsg(null);
     try {
       const patch: ProviderUpdatePatch = { adapter: adapter.trim(), baseUrl: nextBaseUrl, defaultModel: defaultModel.trim(), authMode, note: note.trim(), allowPrivateNetwork, liveModels };
+      if (supportsApiKeyTransport) patch.apiKeyTransport = apiKeyTransport;
+      else if (item.apiKeyTransport !== undefined) patch.apiKeyTransport = "";
       const res = await onUpdateProvider(item.name, patch);
       setMsg(res.ok ? { ok: true, text: t("pws.settingsSaved") } : { ok: false, text: res.error || t("prov.saveFailed") });
       return res.ok;
@@ -153,6 +159,7 @@ export default function ProviderSettings({
   const discard = () => {
     setAdapter(item.adapter); setBaseUrl(item.baseUrl);
     setDefaultModel(item.defaultModel ?? ""); setAuthMode(initialAuth);
+    setApiKeyTransport(item.apiKeyTransport ?? "x-api-key");
     setNote(item.note ?? ""); setAllowPrivateNetwork(item.allowPrivateNetwork ?? false); setLiveModels(item.liveModels !== false); setMsg(null);
     setEndpointChoice(matchChoiceId(baseUrlChoices, item.baseUrl));
   };
@@ -233,6 +240,15 @@ export default function ProviderSettings({
           </select>
         )}
       </label>
+      {supportsApiKeyTransport && (
+        <label className="pwi-settings-field">
+          <span className="pwi-settings-label">{t("modal.apiKeyTransport")}</span>
+          <select className="input" value={apiKeyTransport} onChange={e => setApiKeyTransport(e.target.value as "x-api-key" | "bearer")}>
+            <option value="x-api-key">{t("modal.apiKeyTransportNative")}</option>
+            <option value="bearer">{t("modal.apiKeyTransportBearer")}</option>
+          </select>
+        </label>
+      )}
       <label className="pwi-settings-field">
         <span className="pwi-settings-label">{t("pws.note")}</span>
         <textarea className="input pwi-settings-textarea" value={note} onChange={e => setNote(e.target.value)} rows={2} />
diff --git a/gui/src/components/provider-workspace/types.ts b/gui/src/components/provider-workspace/types.ts
index 9bac652a6..3cea9d24b 100644
--- a/gui/src/components/provider-workspace/types.ts
+++ b/gui/src/components/provider-workspace/types.ts
@@ -90,6 +90,7 @@ export type ProviderUpdatePatch = {
   baseUrl?: string;
   defaultModel?: string;
   apiKey?: string;
+  apiKeyTransport?: "x-api-key" | "bearer" | "";
   authMode?: string;
   note?: string;
   disabled?: boolean;
diff --git a/gui/src/i18n/de.ts b/gui/src/i18n/de.ts
index a1bc4d0dd..064ee19d2 100644
--- a/gui/src/i18n/de.ts
+++ b/gui/src/i18n/de.ts
@@ -1260,6 +1260,9 @@ export const de: Record<TKey, string> = {
   "modal.localHint": "Es wird kein API-Schlüssel gespeichert. Damit wird Cursors öffentlicher Modellkatalog für Codex hinzugefügt; live Cursor-Transport und native Datei-/Shell-Ausführung bleiben deaktiviert, bis sie geprüft sind.",
   "modal.getApiKey": "{label}-API-Schlüssel holen",
   "modal.apiKey": "API-Schlüssel",
+  "modal.apiKeyTransport": "API-Schlüssel-Header",
+  "modal.apiKeyTransportNative": "x-api-key (Anthropic-Standard)",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-… (oder $ENV_VAR)",
   "modal.defaultModelPlaceholder": "z. B. gpt-5.5",
  "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/i18n/en.ts b/gui/src/i18n/en.ts
index 64127b608..fcfb9cb0f 100644
--- a/gui/src/i18n/en.ts
+++ b/gui/src/i18n/en.ts
@@ -1023,6 +1023,9 @@ export const en = {
   "modal.localHint": "No API key is stored. This adds Cursor's static public model catalog for Codex, but live Cursor transport and native file/shell execution remain disabled until audited.",
   "modal.getApiKey": "Get your {label} API key",
   "modal.apiKey": "API key",
+  "modal.apiKeyTransport": "API key header",
+  "modal.apiKeyTransportNative": "x-api-key (Anthropic native)",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-… (or $ENV_VAR)",
   "modal.defaultModelPlaceholder": "e.g. gpt-5.5",
  "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/i18n/ja.ts b/gui/src/i18n/ja.ts
index 99dbeb424..77852cb46 100644
--- a/gui/src/i18n/ja.ts
+++ b/gui/src/i18n/ja.ts
@@ -980,6 +980,9 @@ export const ja: Record<TKey, string> = {
   "modal.localHint": "API キーは保存されません。Cursor の静的な公開モデルカタログを Codex に追加しますが、ライブの Cursor トランスポートとネイティブのファイル/シェル実行は監査されるまで無効のままです。",
   "modal.getApiKey": "{label} の API キーを取得",
   "modal.apiKey": "API キー",
+  "modal.apiKeyTransport": "API キーヘッダー",
+  "modal.apiKeyTransportNative": "x-api-key (Anthropic 標準)",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-… (または $ENV_VAR)",
   "modal.defaultModelPlaceholder": "例: gpt-5.5",
   "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/i18n/ko.ts b/gui/src/i18n/ko.ts
index f1b47e23e..d36ede64e 100644
--- a/gui/src/i18n/ko.ts
+++ b/gui/src/i18n/ko.ts
@@ -1280,6 +1280,9 @@ export const ko: Record<TKey, string> = {
   "modal.localHint": "API 키는 저장되지 않습니다. Cursor의 공개 모델 카탈로그만 Codex에 추가되며, live Cursor 전송과 네이티브 파일/셸 실행은 검토 전까지 비활성입니다.",
   "modal.getApiKey": "{label} API 키 받기",
   "modal.apiKey": "API 키",
+  "modal.apiKeyTransport": "API 키 헤더",
+  "modal.apiKeyTransportNative": "x-api-key (Anthropic 기본)",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-… (또는 $ENV_VAR)",
   "modal.defaultModelPlaceholder": "예: gpt-5.5",
  "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/i18n/ru.ts b/gui/src/i18n/ru.ts
index c2c168988..8c22f7c04 100644
--- a/gui/src/i18n/ru.ts
+++ b/gui/src/i18n/ru.ts
@@ -1022,6 +1022,9 @@ export const ru: Record<TKey, string> = {
   "modal.localHint": "API-ключ не сохраняется. Будет добавлен статический публичный каталог моделей Cursor для Codex, но живой транспорт Cursor и нативное выполнение файловых и shell-операций остаются отключёнными до прохождения аудита.",
   "modal.getApiKey": "Получить API-ключ {label}",
   "modal.apiKey": "API-ключ",
+  "modal.apiKeyTransport": "Заголовок API-ключа",
+  "modal.apiKeyTransportNative": "x-api-key (нативный Anthropic)",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-… (или $ENV_VAR)",
   "modal.defaultModelPlaceholder": "напр. gpt-5.5",
   "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/i18n/zh.ts b/gui/src/i18n/zh.ts
index f2c91eb56..2920c7d2f 100644
--- a/gui/src/i18n/zh.ts
+++ b/gui/src/i18n/zh.ts
@@ -1280,6 +1280,9 @@ export const zh: Record<TKey, string> = {
   "modal.localHint": "不会存储 API 密钥。这会为 Codex 添加 Cursor 的公开模型目录，但在审计完成前，实时 Cursor 传输与原生文件/Shell 执行仍保持禁用。",
   "modal.getApiKey": "获取 {label} API 密钥",
   "modal.apiKey": "API 密钥",
+  "modal.apiKeyTransport": "API 密钥请求头",
+  "modal.apiKeyTransportNative": "x-api-key（Anthropic 原生）",
+  "modal.apiKeyTransportBearer": "Authorization: Bearer",
   "modal.apiKeyPlaceholder": "sk-…（或 $ENV_VAR）",
   "modal.defaultModelPlaceholder": "例如 gpt-5.5",
  "modal.baseUrlPlaceholder": "https://...",
diff --git a/gui/src/provider-payload.ts b/gui/src/provider-payload.ts
index c16e56b4b..bfa150fb7 100644
--- a/gui/src/provider-payload.ts
+++ b/gui/src/provider-payload.ts
@@ -4,6 +4,7 @@ export interface ProviderPayloadForm {
   baseUrl: string;
   authMode: "key" | "forward" | "oauth" | "local";
   apiKey: string;
+  apiKeyTransport?: "x-api-key" | "bearer";
   defaultModel: string;
   allowPrivateNetwork?: boolean;
 }
@@ -70,6 +71,7 @@ export interface ProviderPayload {
   adapter: string;
   baseUrl: string;
   apiKey?: string;
+  apiKeyTransport?: "x-api-key" | "bearer";
   defaultModel?: string;
   authMode?: "key" | "forward" | "oauth";
   codexAccountMode?: "pool" | "direct";
@@ -88,6 +90,9 @@ export function buildProviderPayload(form: ProviderPayloadForm): ProviderPayload
   if (form.authMode === "key" && form.apiKey.trim()) {
     provider.apiKey = form.apiKey.trim();
   }
+  if (form.adapter.trim() === "anthropic" && form.authMode === "key" && form.apiKeyTransport === "bearer") {
+    provider.apiKeyTransport = "bearer";
+  }
   if (form.defaultModel.trim()) {
     provider.defaultModel = form.defaultModel.trim();
   }
diff --git a/gui/src/provider-workspace/catalog.ts b/gui/src/provider-workspace/catalog.ts
index b2568780d..532b164e4 100644
--- a/gui/src/provider-workspace/catalog.ts
+++ b/gui/src/provider-workspace/catalog.ts
@@ -33,6 +33,7 @@ export interface WorkspaceProvider {
   hasApiKey?: boolean;
   hasHeaders?: boolean;
   defaultModel?: string;
+  apiKeyTransport?: "x-api-key" | "bearer";
   /** Static/configured model ids from provider config (offline fallback). */
   models?: string[];
   /** Whether the proxy fetches the provider's live model catalog (default true). */
diff --git a/src/adapters/anthropic.ts b/src/adapters/anthropic.ts
index cb8e73d7b..714fedac0 100644
--- a/src/adapters/anthropic.ts
+++ b/src/adapters/anthropic.ts
@@ -250,6 +250,10 @@ function usesNativeAnthropicEndpoint(provider: OcxProviderConfig): boolean {
   }
 }
 
+function anthropicKeyUsesBearer(provider: OcxProviderConfig): boolean {
+  return provider.apiKeyTransport === "bearer";
+}
+
 /** Map a Responses reasoning effort to an Anthropic extended-thinking budget (tokens, >= 1024). */
 function reasoningBudget(effort: string): number {
   switch (effort) {
@@ -694,7 +698,8 @@ export function createAnthropicAdapter(provider: OcxProviderConfig, cacheRetenti
         headers["X-Claude-Code-Session-Id"] = claudeCodeSessionId(provider.apiKey);
         headers["x-client-request-id"] = crypto.randomUUID();
       } else {
-        headers["x-api-key"] = provider.apiKey;
+        if (anthropicKeyUsesBearer(provider)) headers["Authorization"] = `Bearer ${provider.apiKey}`;
+        else headers["x-api-key"] = provider.apiKey;
       }
       if (provider.headers) Object.assign(headers, provider.headers);
 
diff --git a/src/cli/provider-runtime.ts b/src/cli/provider-runtime.ts
index 7358bf51c..28647c45c 100644
--- a/src/cli/provider-runtime.ts
+++ b/src/cli/provider-runtime.ts
@@ -15,6 +15,7 @@ import {
 const USAGE = `Usage:
   ocx provider edit <name> [--adapter <id>] [--base-url <url>] [--default-model <id|->]
       [--auth-mode <key|forward|oauth|local|->] [--note <text|->]
+      [--api-key-transport <x-api-key|bearer|->]
       [--enabled <on|off>] [--live-models <on|off>] [--allow-private-network <on|off>] [--json]
   ocx provider test <name> [--json]
   ocx provider quota [--refresh] [--json]
@@ -37,6 +38,7 @@ async function edit(argv: string[], deps: RuntimeApiDeps): Promise<void> {
   const defaultModel = cleared(takeOption(args, "--default-model"));
   const authMode = cleared(takeOption(args, "--auth-mode"));
   const note = cleared(takeOption(args, "--note"));
+  const apiKeyTransport = cleared(takeOption(args, "--api-key-transport"));
   const enabled = takeBooleanOption(args, "--enabled");
   const liveModels = takeBooleanOption(args, "--live-models");
   const allowPrivateNetwork = takeBooleanOption(args, "--allow-private-network");
@@ -46,6 +48,7 @@ async function edit(argv: string[], deps: RuntimeApiDeps): Promise<void> {
   if (defaultModel !== undefined) patch.defaultModel = defaultModel;
   if (authMode !== undefined) patch.authMode = authMode;
   if (note !== undefined) patch.note = note;
+  if (apiKeyTransport !== undefined) patch.apiKeyTransport = apiKeyTransport;
   if (enabled !== undefined) patch.disabled = !enabled;
   if (liveModels !== undefined) patch.liveModels = liveModels;
   if (allowPrivateNetwork !== undefined) patch.allowPrivateNetwork = allowPrivateNetwork;
diff --git a/src/cli/provider.ts b/src/cli/provider.ts
index 6c3d27c91..dd218be95 100644
--- a/src/cli/provider.ts
+++ b/src/cli/provider.ts
@@ -8,7 +8,7 @@
  *   show <name>   Show provider config details (secrets masked)
  *   set-default <name>  Change the default provider
  */
-import { hasOwnProvider, isValidProviderName, loadConfig, saveConfig } from "../config";
+import { apiKeyTransportConfigError, hasOwnProvider, isValidProviderName, loadConfig, saveConfig } from "../config";
 import { hasHelpFlag } from "./help";
 import { getProviderRegistryEntry, PROVIDER_REGISTRY } from "../providers/registry";
 import { providerConfigSeed } from "../providers/derive";
@@ -124,7 +124,7 @@ function handleList(args: string[]): void {
 // provider add
 // ---------------------------------------------------------------------------
 
-const ADD_USAGE = "Usage: ocx provider add <name> [--adapter <adapter>] [--base-url <url>] [--api-key <key>] [--default-model <model>] [--allow-private-network] [--set-default] [--force] [--json] [--sync]";
+const ADD_USAGE = "Usage: ocx provider add <name> [--adapter <adapter>] [--base-url <url>] [--api-key <key>] [--api-key-transport <x-api-key|bearer>] [--default-model <model>] [--allow-private-network] [--set-default] [--force] [--json] [--sync]";
 
 async function handleAdd(args: string[]): Promise<void> {
   const name = args[0];
@@ -138,13 +138,14 @@ async function handleAdd(args: string[]): Promise<void> {
     process.exit(1);
   }
 
- const restArgs = args.slice(1);
- const force = consumeFlag(restArgs, "--force");
- const setDefault = consumeFlag(restArgs, "--set-default");
- const wantsJson = consumeFlag(restArgs, "--json");
- const wantsSync = consumeFlag(restArgs, "--sync");
+  const restArgs = args.slice(1);
+  const force = consumeFlag(restArgs, "--force");
+  const setDefault = consumeFlag(restArgs, "--set-default");
+  const wantsJson = consumeFlag(restArgs, "--json");
+  const wantsSync = consumeFlag(restArgs, "--sync");
   const allowPrivateNetwork = consumeFlag(restArgs, "--allow-private-network");
- const apiKey = consumeFlagValue(restArgs, "--api-key");
+  const apiKey = consumeFlagValue(restArgs, "--api-key");
+  const apiKeyTransport = consumeFlagValue(restArgs, "--api-key-transport");
   const adapter = consumeFlagValue(restArgs, "--adapter");
   const baseUrl = consumeFlagValue(restArgs, "--base-url");
   const defaultModel = consumeFlagValue(restArgs, "--default-model");
@@ -188,9 +189,22 @@ async function handleAdd(args: string[]): Promise<void> {
     };
   }
 
- config.providers[name] = provConfig;
+  if (apiKeyTransport !== undefined) {
+    if (apiKeyTransport !== "x-api-key" && apiKeyTransport !== "bearer") {
+      console.error('Error: --api-key-transport must be "x-api-key" or "bearer".');
+      process.exit(1);
+    }
+    const transportError = apiKeyTransportConfigError({ ...provConfig, apiKeyTransport });
+    if (transportError) {
+      console.error(`Error: ${transportError}.`);
+      process.exit(1);
+    }
+    provConfig.apiKeyTransport = apiKeyTransport;
+  }
+
+  config.providers[name] = provConfig;
   if (allowPrivateNetwork) provConfig.allowPrivateNetwork = true;
- if (setDefault) config.defaultProvider = name;
+  if (setDefault) config.defaultProvider = name;
 
   validateAndSave(config);
 
diff --git a/src/config.ts b/src/config.ts
index 68adef296..1168e0e4e 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -339,6 +339,7 @@ const warnedConfigFallbacks = new Set<string>();
 const providerConfigSchema = z.object({
   adapter: z.string().min(1),
   baseUrl: z.string().min(1),
+  apiKeyTransport: z.enum(["x-api-key", "bearer"]).optional(),
   responsesPath: z.string().min(1).optional(),
   allowPrivateNetwork: z.boolean().optional(),
   codexAccountMode: z.enum(["pool", "direct"]).optional(),
@@ -410,6 +411,23 @@ export function providerHeadersConfigError(headers: unknown): string | null {
   return null;
 }
 
+/** Keep the configured API-key header style scoped to Anthropic-compatible key auth. */
+export function apiKeyTransportConfigError(
+  provider: Pick<OcxProviderConfig, "adapter" | "authMode" | "apiKeyTransport">,
+): string | null {
+  if (provider.apiKeyTransport === undefined) return null;
+  if (provider.apiKeyTransport !== "x-api-key" && provider.apiKeyTransport !== "bearer") {
+    return 'apiKeyTransport must be "x-api-key" or "bearer"';
+  }
+  if (provider.adapter !== "anthropic") {
+    return "apiKeyTransport is supported only by the anthropic adapter";
+  }
+  if (provider.authMode === "oauth" || provider.authMode === "forward" || provider.authMode === "local") {
+    return "apiKeyTransport requires Anthropic API-key authentication";
+  }
+  return null;
+}
+
 export function positiveIntegerRecordConfigError(value: unknown, field: string): string | null {
   if (value === undefined) return null;
   if (!value || typeof value !== "object" || Array.isArray(value)) return `${field} must be a plain object`;
@@ -607,6 +625,14 @@ const configSchema = z.object({
         message: headersError,
       });
     }
+    const apiKeyTransportError = apiKeyTransportConfigError(provider as OcxProviderConfig);
+    if (apiKeyTransportError) {
+      ctx.addIssue({
+        code: "custom",
+        path: ["providers", name, "apiKeyTransport"],
+        message: apiKeyTransportError,
+      });
+    }
     const modelAdaptersError = modelAdapterRecordConfigError(
       (provider as { modelAdapters?: unknown }).modelAdapters,
       "modelAdapters",
diff --git a/src/oauth/index.ts b/src/oauth/index.ts
index 2eb48de77..c6dca4bc0 100644
--- a/src/oauth/index.ts
+++ b/src/oauth/index.ts
@@ -464,8 +464,9 @@ export async function resolveModelsAuthToken(name: string, prov: OcxProviderConf
 /**
  * Provider-correct `GET /models` request (URL + headers), so both model-listing paths fetch the
  * LIVE catalog correctly per adapter. Anthropic is the special case: its endpoint is `/v1/models`
- * (not `/models`), it needs `anthropic-version`, and it authenticates with `x-api-key` (key) or
- * `Authorization: Bearer` + the OAuth beta (oauth) — not a bare Bearer. Google (ai-studio mode)
+ * (not `/models`), it needs `anthropic-version`, and it authenticates with `x-api-key` by default
+ * (or `Authorization: Bearer` when `apiKeyTransport = "bearer"`), plus the OAuth beta for oauth
+ * mode — not a bare Bearer. Google (ai-studio mode)
  * is the other special case: `x-goog-api-key` + `/v1beta/models`, returning `{ models: [...] }`.
  * The catalog authority gate intentionally degrades that non-OpenAI shape to stale/static data.
  * Everyone else uses the OpenAI-style `/models` + Bearer with a `{ data: [{ id, owned_by? }] }`
@@ -488,14 +489,16 @@ export function buildModelsRequest(prov: OcxProviderConfig, apiKey: string | und
     return { url: `${effectiveProvider.baseUrl}/v1beta/models?pageSize=1000`, headers };
   }
   if (effectiveProvider.adapter === "anthropic") {
+    const base = effectiveProvider.baseUrl.replace(/\/v1\/?$/, "");
     headers["anthropic-version"] = "2023-06-01";
     if (effectiveProvider.authMode === "oauth") {
       headers["anthropic-beta"] = ANTHROPIC_OAUTH_BETA;
       if (apiKey) headers["Authorization"] = `Bearer ${apiKey}`;
     } else if (apiKey) {
-      headers["x-api-key"] = apiKey;
+      if (effectiveProvider.apiKeyTransport === "bearer") headers["Authorization"] = `Bearer ${apiKey}`;
+      else headers["x-api-key"] = apiKey;
     }
-    return { url: `${effectiveProvider.baseUrl}/v1/models?limit=1000`, headers };
+    return { url: `${base}/v1/models?limit=1000`, headers };
   }
   if (apiKey) headers["Authorization"] = `Bearer ${apiKey}`;
   return { url: `${effectiveProvider.baseUrl}/models`, headers };
diff --git a/src/oauth/key-providers.ts b/src/oauth/key-providers.ts
index a0ef0a820..f33223678 100644
--- a/src/oauth/key-providers.ts
+++ b/src/oauth/key-providers.ts
@@ -5,7 +5,8 @@ import { deriveKeyLoginMap, enrichProviderFromRegistry, type DerivedKeyLoginProv
  * API-key "login" providers: not OAuth — the flow opens the provider's dashboard so the user can
  * create/copy a key, then validates + stores it as the provider's `apiKey` (authMode "key").
  * Most use the OpenAI-compatible chat API (`openai-chat` adapter, `Authorization: Bearer <key>`); a
- * few expose only an Anthropic-compatible endpoint and set `adapter: "anthropic"` (`x-api-key`).
+ * few expose only an Anthropic-compatible endpoint and set `adapter: "anthropic"` (default
+ * `x-api-key`, optional bearer via `apiKeyTransport`).
  */
 export interface KeyLoginProvider extends DerivedKeyLoginProvider {}
 
@@ -29,6 +30,20 @@ export function listKeyLoginProviders(): Array<{ id: string } & KeyLoginProvider
   return Object.entries(KEY_LOGIN_PROVIDERS).map(([id, p]) => ({ id, ...p }));
 }
 
+function anthropicKeyValidationHeaders(provider: Pick<KeyLoginProvider, "apiKeyTransport">, key: string): HeadersInit {
+  return provider.apiKeyTransport === "bearer"
+    ? {
+      "Content-Type": "application/json",
+      "anthropic-version": "2023-06-01",
+      "Authorization": `Bearer ${key}`,
+    }
+    : {
+      "Content-Type": "application/json",
+      "anthropic-version": "2023-06-01",
+      "x-api-key": key,
+    };
+}
+
 /** Best-effort key validation. Returns true/false/unknown; never persists the key itself. */
 export async function validateApiKey(provider: KeyLoginProvider, key: string): Promise<boolean | "unknown"> {
   try {
@@ -36,11 +51,7 @@ export async function validateApiKey(provider: KeyLoginProvider, key: string): P
       const base = provider.baseUrl.replace(/\/v1\/?$/, "");
       const res = await fetch(`${base}/v1/messages`, {
         method: "POST",
-        headers: {
-          "Content-Type": "application/json",
-          "anthropic-version": "2023-06-01",
-          "x-api-key": key,
-        },
+        headers: anthropicKeyValidationHeaders(provider, key),
         body: JSON.stringify({
           model: provider.defaultModel ?? "claude-haiku-4-5",
           max_tokens: 1,
diff --git a/src/oauth/login-cli.ts b/src/oauth/login-cli.ts
index 1c7dfae2e..cf225b9ce 100644
--- a/src/oauth/login-cli.ts
+++ b/src/oauth/login-cli.ts
@@ -80,6 +80,7 @@ export function providerConfigFromKeyLoginProvider(def: KeyLoginProvider, key: s
     adapter: def.adapter,
     baseUrl: baseUrlOverride ?? def.baseUrl,
     apiKey: key,
+    ...(def.apiKeyTransport !== undefined ? { apiKeyTransport: def.apiKeyTransport } : {}),
     ...(def.defaultModel ? { defaultModel: def.defaultModel } : {}),
     ...(def.models ? { models: [...def.models] } : {}),
     ...(def.contextWindow !== undefined ? { contextWindow: def.contextWindow } : {}),
diff --git a/src/providers/derive.ts b/src/providers/derive.ts
index d24f852dd..b3a677ea5 100644
--- a/src/providers/derive.ts
+++ b/src/providers/derive.ts
@@ -5,6 +5,7 @@ export interface DerivedKeyLoginProvider {
   label: string;
   baseUrl: string;
   adapter: string;
+  apiKeyTransport?: OcxProviderConfig["apiKeyTransport"];
   dashboardUrl: string;
   models?: string[];
   liveModels?: boolean;
@@ -103,6 +104,7 @@ export function providerConfigSeed(entry: ProviderRegistryEntry): OcxProviderCon
   return {
     adapter: entry.adapter,
     baseUrl: entry.baseUrl,
+    ...(entry.apiKeyTransport !== undefined ? { apiKeyTransport: entry.apiKeyTransport } : {}),
     authMode: entry.authKind === "local" ? undefined : entry.authKind,
     ...(entry.codexAccountMode ? { codexAccountMode: entry.codexAccountMode } : {}),
     ...(entry.keyOptional !== undefined ? { keyOptional: entry.keyOptional } : {}),
@@ -150,6 +152,7 @@ export function deriveKeyLoginMap(): Record<string, DerivedKeyLoginProvider> {
       label: entry.label,
       baseUrl: entry.baseUrl,
       adapter: entry.adapter,
+      ...(entry.apiKeyTransport !== undefined ? { apiKeyTransport: entry.apiKeyTransport } : {}),
       dashboardUrl: entry.dashboardUrl,
       ...(entry.models ? { models: [...entry.models] } : {}),
       ...(entry.liveModels !== undefined ? { liveModels: entry.liveModels } : {}),
@@ -221,6 +224,7 @@ export function enrichProviderFromRegistry(name: string, prov: OcxProviderConfig
   const entry = PROVIDER_REGISTRY.find(row => row.id === name);
   if (!entry) return;
   const seed = providerConfigSeed(entry);
+  if (prov.apiKeyTransport === undefined && seed.apiKeyTransport !== undefined) prov.apiKeyTransport = seed.apiKeyTransport;
   if (!prov.defaultModel && seed.defaultModel) prov.defaultModel = seed.defaultModel;
   // Fill mode only when absent: an explicit persisted `direct` must never be overwritten.
   if (prov.codexAccountMode === undefined && seed.codexAccountMode !== undefined) prov.codexAccountMode = seed.codexAccountMode;
diff --git a/src/providers/registry.ts b/src/providers/registry.ts
index 5552b845f..235a20f58 100644
--- a/src/providers/registry.ts
+++ b/src/providers/registry.ts
@@ -22,6 +22,7 @@ export interface ProviderRegistryEntry {
   label: string;
   adapter: string;
   baseUrl: string;
+  apiKeyTransport?: OcxProviderConfig["apiKeyTransport"];
   authKind: ProviderAuthKind;
   codexAccountMode?: CodexAccountMode;
   /** OAuth preset may explicitly honor a persisted API-key billing mode. */
@@ -88,7 +89,7 @@ export interface ProviderRegistryEntry {
 
 export type ProviderConfigSeed = Pick<
   OcxProviderConfig,
-  "adapter" | "baseUrl" | "authMode" | "keyOptional" | "freeTier" | "modelSuffixBracketStrip" | "defaultModel" | "models"
+  "adapter" | "baseUrl" | "apiKeyTransport" | "authMode" | "keyOptional" | "freeTier" | "modelSuffixBracketStrip" | "defaultModel" | "models"
   | "liveModels" | "contextWindow" | "modelContextWindows" | "modelInputModalities"
   | "modelMaxInputTokens" | "defaultMaxOutputTokens" | "modelMaxOutputTokens"
   | "reasoningEfforts" | "modelReasoningEfforts" | "modelDefaultReasoningEfforts" | "reasoningEffortMap" | "modelReasoningEffortMap"
diff --git a/src/server/auth-cors.ts b/src/server/auth-cors.ts
index b8b62fc00..b067f7130 100644
--- a/src/server/auth-cors.ts
+++ b/src/server/auth-cors.ts
@@ -1,6 +1,7 @@
 import { timingSafeEqual } from "node:crypto";
 import { formatErrorResponse } from "../bridge";
 import {
+  apiKeyTransportConfigError,
   booleanRecordConfigError,
   modelAdapterRecordConfigError,
   codexAutoStartEnabled,
@@ -245,6 +246,8 @@ export function providerManagementConfigError(name: unknown, provider: unknown):
   if (destinationError) return `provider ${name} ${destinationError}`;
   const headersError = providerHeadersConfigError(typed.headers);
   if (headersError) return `provider ${name} ${headersError}`;
+  const apiKeyTransportError = apiKeyTransportConfigError(typed);
+  if (apiKeyTransportError) return `provider ${name} ${apiKeyTransportError}`;
   const maxInputError = positiveIntegerRecordConfigError(raw.modelMaxInputTokens, "modelMaxInputTokens");
   if (maxInputError) return `provider ${name} ${maxInputError}`;
   const reasoningSummariesError = booleanRecordConfigError(raw.modelSupportsReasoningSummaries, "modelSupportsReasoningSummaries");
@@ -320,6 +323,7 @@ export function safeConfigDTO(config: OcxConfig): unknown {
       "disabled",
       "allowPrivateNetwork",
       "authMode",
+      "apiKeyTransport",
       "keyOptional",
       "freeTier",
       "liveModels",
diff --git a/src/server/management/provider-routes.ts b/src/server/management/provider-routes.ts
index 7d8cd65c6..53d17ff10 100644
--- a/src/server/management/provider-routes.ts
+++ b/src/server/management/provider-routes.ts
@@ -76,6 +76,7 @@ export async function handleProviderRoutes(ctx: ManagementContext): Promise<Resp
       liveModels: p.liveModels !== false,
       models: p.models ?? [],
       authMode: p.authMode,
+      apiKeyTransport: p.apiKeyTransport,
       disabled: p.disabled === true,
       codexAccountMode: providerCodexAccountMode(name, p),
       discovery: p.liveModels === false ? undefined : getProviderDiscoveryStatus(name),
@@ -213,6 +214,18 @@ export async function handleProviderRoutes(ctx: ManagementContext): Promise<Resp
         return jsonResponse({ error: "authMode must be key, forward, oauth, or local" }, 400);
       }
     }
+    if (Object.hasOwn(rawBody, "apiKeyTransport")) {
+      const transport = rawBody.apiKeyTransport;
+      if (transport === "x-api-key" || transport === "bearer") {
+        next.apiKeyTransport = transport;
+        touched = true;
+      } else if (transport === "") {
+        delete next.apiKeyTransport;
+        touched = true;
+      } else {
+        return jsonResponse({ error: "apiKeyTransport must be x-api-key, bearer, or empty to clear" }, 400);
+      }
+    }
    if (Object.hasOwn(rawBody, "note")) {
      if (typeof rawBody.note !== "string") return jsonResponse({ error: "note must be a string" }, 400);
      const note = rawBody.note.trim();
diff --git a/src/types.ts b/src/types.ts
index 622e4ec16..d8d286858 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -873,6 +873,12 @@ export interface OcxProviderConfig {
    */
   codexAccountMode?: CodexAccountMode;
   apiKey?: string;
+  /**
+   * Key-auth header style for Anthropic-compatible providers.
+   * Defaults to the native Anthropic `x-api-key`; gateways may require
+   * `Authorization: Bearer <key>` instead.
+   */
+  apiKeyTransport?: "x-api-key" | "bearer";
   /**
    * Multi-key pool (API-key twin of OAuth multiauth). `apiKey` always mirrors the ACTIVE
    * entry so routing stays single-key; managed via /api/providers/keys. A legacy bare
diff --git a/tests/cli-headless-parity.test.ts b/tests/cli-headless-parity.test.ts
index dbd22efc6..78b030a85 100644
--- a/tests/cli-headless-parity.test.ts
+++ b/tests/cli-headless-parity.test.ts
@@ -94,13 +94,13 @@ describe("headless GUI parity CLI", () => {
   test("provider edit reuses the management provider patch", async () => {
     const runtime = fakeRuntime();
     const code = await handleProviderRuntimeCommand("edit", [
-      "ark", "--base-url", "https://example.test/v1", "--enabled", "off", "--live-models", "on", "--json",
+      "ark", "--base-url", "https://example.test/v1", "--api-key-transport", "bearer", "--enabled", "off", "--live-models", "on", "--json",
     ], runtime.deps);
     expect(code).toBe(0);
     expect(runtime.requests).toEqual([{
       path: "/api/providers?name=ark",
       method: "PATCH",
-      body: { baseUrl: "https://example.test/v1", disabled: true, liveModels: true },
+      body: { baseUrl: "https://example.test/v1", apiKeyTransport: "bearer", disabled: true, liveModels: true },
     }]);
   });
 
diff --git a/tests/config.test.ts b/tests/config.test.ts
index a53ae79b7..54cfa7292 100644
--- a/tests/config.test.ts
+++ b/tests/config.test.ts
@@ -616,6 +616,26 @@ describe("opencodex config defaults", () => {
     }
   });
 
+  test("accepts bearer transport only for Anthropic API-key providers", () => {
+    const base = { port: 10100, defaultProvider: "gateway" };
+    writeConfig({
+      ...base,
+      providers: {
+        gateway: { adapter: "anthropic", baseUrl: "https://gateway.example/v1", authMode: "key", apiKeyTransport: "bearer" },
+      },
+    });
+    expect(readConfigDiagnostics().error).toBeNull();
+
+    for (const provider of [
+      { adapter: "openai-chat", baseUrl: "https://gateway.example/v1", authMode: "key", apiKeyTransport: "bearer" },
+      { adapter: "anthropic", baseUrl: "https://gateway.example/v1", authMode: "oauth", apiKeyTransport: "bearer" },
+    ]) {
+      writeConfig({ ...base, providers: { gateway: provider } });
+      expect(readConfigDiagnostics().source).toBe("fallback");
+      expect(readConfigDiagnostics().error).toContain("apiKeyTransport");
+    }
+  });
+
   test("validates provider context cap maps explicitly", () => {
     writeConfig({
       port: 10100,
diff --git a/tests/google-models-listing.test.ts b/tests/google-models-listing.test.ts
index f31bd1341..c0d61fd3b 100644
--- a/tests/google-models-listing.test.ts
+++ b/tests/google-models-listing.test.ts
@@ -49,6 +49,34 @@ describe("buildModelsRequest google routing", () => {
   });
 });
 
+describe("buildModelsRequest anthropic routing", () => {
+  test("normalizes a /v1 baseUrl and keeps the Anthropic models path singular", () => {
+    const prov = {
+      adapter: "anthropic",
+      authMode: "key",
+      apiKeyTransport: "bearer",
+      baseUrl: "https://gateway.example.com/v1",
+    } as OcxProviderConfig;
+    const { url, headers } = buildModelsRequest(prov, "sk-ant", "gateway");
+    expect(url).toBe("https://gateway.example.com/v1/models?limit=1000");
+    expect(headers["Authorization"]).toBe("Bearer sk-ant");
+    expect(headers["x-api-key"]).toBeUndefined();
+    expect(headers["anthropic-version"]).toBe("2023-06-01");
+  });
+
+  test("uses x-api-key by default for key-auth Anthropic providers", () => {
+    const prov = {
+      adapter: "anthropic",
+      authMode: "key",
+      baseUrl: "https://gateway.example.com",
+    } as OcxProviderConfig;
+    const { url, headers } = buildModelsRequest(prov, "sk-ant", "gateway");
+    expect(url).toBe("https://gateway.example.com/v1/models?limit=1000");
+    expect(headers["x-api-key"]).toBe("sk-ant");
+    expect(headers["Authorization"]).toBeUndefined();
+  });
+});
+
 describe("google models listing via catalog", () => {
   test("treats a { models } 2xx shape as malformed and degrades to the static seed", async () => {
     clearModelCache("google");
diff --git a/tests/management-provider-validation.test.ts b/tests/management-provider-validation.test.ts
index 35f56dcd8..dd11eacb2 100644
--- a/tests/management-provider-validation.test.ts
+++ b/tests/management-provider-validation.test.ts
@@ -1593,6 +1593,7 @@ describe("provider management validation", () => {
       providers: {
         openai: { ...canonicalDirect },
         extra: { adapter: "openai-chat", baseUrl: "https://extra.example.test/v1", apiKey: "sk-existing", note: "old note" },
+        gateway: { adapter: "anthropic", baseUrl: "https://gateway.example.test/v1", apiKey: "sk-gateway" },
         nvidia: { adapter: "openai-chat", baseUrl: "https://integrate.api.nvidia.com/v1", apiKey: "sk-nvidia" },
         ollama: { adapter: "openai-chat", baseUrl: "http://localhost:11434/v1" },
       },
@@ -1634,6 +1635,17 @@ describe("provider management validation", () => {
     expect(await keyWrite?.json()).toMatchObject({ error: expect.stringContaining("API-key endpoints") });
     expect(liveConfig.providers.extra.apiKey).toBe("sk-existing");
 
+    // Key-auth Anthropic gateways can select bearer; other adapters and auth modes cannot.
+    const bearer = await patch("gateway", { apiKeyTransport: "bearer" });
+    expect(bearer?.status).toBe(200);
+    expect(liveConfig.providers.gateway.apiKeyTransport).toBe("bearer");
+    expect((await patch("gateway", { apiKeyTransport: "invalid" }))?.status).toBe(400);
+    expect((await patch("extra", { apiKeyTransport: "bearer" }))?.status).toBe(400);
+    expect((await patch("gateway", { authMode: "oauth" }))?.status).toBe(400);
+    const clearTransport = await patch("gateway", { apiKeyTransport: "" });
+    expect(clearTransport?.status).toBe(200);
+    expect(liveConfig.providers.gateway.apiKeyTransport).toBeUndefined();
+
     // authMode local is guarded by the registry: nvidia (key) → 400; ollama (local) → ok.
     const nvidiaLocal = await patch("nvidia", { authMode: "local" });
     expect(nvidiaLocal?.status).toBe(400);
diff --git a/tests/provider-payload.test.ts b/tests/provider-payload.test.ts
index 0cb8ad26a..5bda1ccab 100644
--- a/tests/provider-payload.test.ts
+++ b/tests/provider-payload.test.ts
@@ -165,6 +165,25 @@ describe("provider dashboard payload", () => {
     });
   });
 
+  test("persists bearer transport only for Anthropic API-key providers", () => {
+    const bearerGateway = {
+      name: "gateway",
+      adapter: "anthropic",
+      baseUrl: "https://gateway.example/v1",
+      authMode: "key" as const,
+      apiKey: " gateway-key ",
+      apiKeyTransport: "bearer" as const,
+      defaultModel: "claude-gateway",
+    };
+    expect(buildProviderPayload(bearerGateway)).toMatchObject({
+      adapter: "anthropic",
+      authMode: "key",
+      apiKey: "gateway-key",
+      apiKeyTransport: "bearer",
+    });
+    expect(buildProviderPayload({ ...bearerGateway, adapter: "openai-chat" })).not.toHaveProperty("apiKeyTransport");
+  });
+
   test("does not persist secrets for forward or local modes", () => {
     const base = {
       name: "local",
diff --git a/tests/umans-provider.test.ts b/tests/umans-provider.test.ts
index 5e8ba72ba..36f2faa4a 100644
--- a/tests/umans-provider.test.ts
+++ b/tests/umans-provider.test.ts
@@ -1,14 +1,15 @@
 import { afterEach, describe, expect, test } from "bun:test";
 import { createAnthropicAdapter } from "../src/adapters/anthropic";
 import { providerConfigFromKeyLoginProvider } from "../src/oauth/login-cli";
-import { enrichProviderFromCatalog, KEY_LOGIN_PROVIDERS, validateApiKey } from "../src/oauth/key-providers";
+import { enrichProviderFromCatalog, KEY_LOGIN_PROVIDERS, validateApiKey, type KeyLoginProvider } from "../src/oauth/key-providers";
 import type { AdapterEvent, OcxParsedRequest, OcxProviderConfig } from "../src/types";
 
-function umansProvider(apiKey = "sk-umans"): OcxProviderConfig {
+function umansProvider(apiKey = "sk-umans", apiKeyTransport?: OcxProviderConfig["apiKeyTransport"]): OcxProviderConfig {
   return {
     adapter: "anthropic",
     baseUrl: "https://api.code.umans.ai",
     apiKey,
+    ...(apiKeyTransport ? { apiKeyTransport } : {}),
     defaultModel: "umans-coder",
     escapeBuiltinToolNames: true,
   };
@@ -81,6 +82,16 @@ describe("Umans provider", () => {
     expect(provider.modelInputModalities?.["umans-kimi-k2.7"]).toEqual(["text", "image"]);
   });
 
+  test("CLI key-login save payload preserves apiKeyTransport when configured", () => {
+    const bearerGateway = {
+      ...KEY_LOGIN_PROVIDERS.umans,
+      apiKeyTransport: "bearer",
+    } satisfies KeyLoginProvider;
+    const provider = providerConfigFromKeyLoginProvider(bearerGateway, "sk-umans");
+
+    expect(provider.apiKeyTransport).toBe("bearer");
+  });
+
   test("OpenAI API key-login clones max-input metadata and never persists virtual maps", () => {
     const source = KEY_LOGIN_PROVIDERS["openai-apikey"];
     const provider = providerConfigFromKeyLoginProvider(source, "sk-openai");
@@ -113,6 +124,14 @@ describe("Umans provider", () => {
     expect(body.tool_choice).toEqual({ type: "tool", name: "cx_web_search" });
   });
 
+  test("Anthropic adapter honors apiKeyTransport=bearer for key-auth gateways", async () => {
+    const req = await createAnthropicAdapter(umansProvider("sk-umans", "bearer")).buildRequest(parsedWithWebSearchTool());
+
+    expect(req.headers.Authorization).toBe("Bearer sk-umans");
+    expect(req.headers["x-api-key"]).toBeUndefined();
+    expect(req.headers["anthropic-version"]).toBe("2023-06-01");
+  });
+
   test("Anthropic adapter filters Umans tools for Responses allowed_tools choices", async () => {
     const req = await createAnthropicAdapter(umansProvider()).buildRequest({
       modelId: "umans-kimi-k2.7",
@@ -208,4 +227,23 @@ describe("Umans provider", () => {
     expect(body.model).toBe("umans-coder");
     expect(body.max_tokens).toBe(1);
   });
+
+  test("Anthropic API-key validation honors apiKeyTransport=bearer", async () => {
+    let seenInit: RequestInit | undefined;
+    globalThis.fetch = (async (_url, init) => {
+      seenInit = init;
+      return new Response("{}", { status: 200 });
+    }) as typeof fetch;
+
+    const valid = await validateApiKey({
+      ...KEY_LOGIN_PROVIDERS.umans,
+      apiKeyTransport: "bearer",
+    }, "sk-umans-valid");
+    const headers = new Headers(seenInit?.headers);
+
+    expect(valid).toBe(true);
+    expect(headers.get("authorization")).toBe("Bearer sk-umans-valid");
+    expect(headers.get("x-api-key")).toBeNull();
+    expect(headers.get("anthropic-version")).toBe("2023-06-01");
+  });
 });