diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4a2693f1f..978eae4e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,20 @@
# Changelog
+## [Unreleased]
+
+### Fixed
+
+- **The AI server key reaches Anthropic when the base URL points there.** An
+ operator who filled the server key with an Anthropic key and
+ `https://api.anthropic.com/v1` got a failure on every AI call and nothing
+ saying why: the request was built for OpenAI's API and posted at Anthropic's,
+ which speaks a different shape. The base URL now picks the client. Anthropic's
+ host, and any subdomain of it, is called on Anthropic's Messages API and
+ defaults to a Claude model; every other host keeps the OpenAI-compatible API
+ it had before, which is also the right one for a local server or a gateway. A
+ base URL that is not a URL at all behaves as it did. The operator card now
+ says which providers the field accepts. Found in a fork by @sweidinger.
+
## [1.38.3] — 2026-09-02
An account with two-factor can be deleted from the phone, and every data
diff --git a/messages/de.json b/messages/de.json
index 3445309ab..ae260abd6 100644
--- a/messages/de.json
+++ b/messages/de.json
@@ -6473,6 +6473,7 @@
"description": "Ein Betreiber-Schlüssel für Konten, die keinen eigenen hinterlegt haben.",
"byokHint": "Der eigene Schlüssel (BYOK, ChatGPT-Login oder lokaler Provider) hat immer Vorrang — der Server-Schlüssel ist die letzte Stufe der Provider-Kette.",
"consentHint": "Anfragen über den Server-Schlüssel erfordern die aktive KI-Einwilligung der Person; ohne Einwilligungsbeleg wird nichts gesendet.",
+ "baseUrlHint": "Die Basis-URL bestimmt die API: eine Anthropic-URL wie https://api.anthropic.com/v1 wird erkannt, jeder andere Host wird über die OpenAI-kompatible API angesprochen.",
"statusConfigured": "Eingerichtet",
"statusNotConfigured": "Nicht eingerichtet",
"keyLabel": "API-Schlüssel",
diff --git a/messages/en.json b/messages/en.json
index 42b53a7cf..bfbb0ab32 100644
--- a/messages/en.json
+++ b/messages/en.json
@@ -6473,6 +6473,7 @@
"description": "An operator key for accounts that have not configured one of their own.",
"byokHint": "A user's own key (BYOK, ChatGPT login or local provider) always takes precedence — the server key is the last step in the provider chain.",
"consentHint": "Requests over the server key require the user's active AI consent; without a consent receipt nothing is sent.",
+ "baseUrlHint": "The base URL selects the API: an Anthropic URL such as https://api.anthropic.com/v1 is understood, any other host is called on the OpenAI-compatible API.",
"statusConfigured": "Configured",
"statusNotConfigured": "Not configured",
"keyLabel": "API key",
diff --git a/messages/es.json b/messages/es.json
index f24a91a82..2ecddf478 100644
--- a/messages/es.json
+++ b/messages/es.json
@@ -6473,6 +6473,7 @@
"description": "Una clave del operador para las cuentas que no tienen una propia.",
"byokHint": "La clave propia del usuario (BYOK, inicio de sesión de ChatGPT o proveedor local) siempre tiene prioridad — la clave del servidor es el último paso de la cadena de proveedores.",
"consentHint": "Las solicitudes con la clave del servidor requieren el consentimiento de IA activo del usuario; sin un recibo de consentimiento no se envía nada.",
+ "baseUrlHint": "La URL base determina la API: se reconoce una URL de Anthropic como https://api.anthropic.com/v1, cualquier otro host se llama a través de la API compatible con OpenAI.",
"statusConfigured": "Configurada",
"statusNotConfigured": "Sin configurar",
"keyLabel": "Clave de API",
diff --git a/messages/fr.json b/messages/fr.json
index 36901d982..63b62b5ff 100644
--- a/messages/fr.json
+++ b/messages/fr.json
@@ -6473,6 +6473,7 @@
"description": "Une clé de l'opérateur pour les comptes qui n'en ont pas configuré une.",
"byokHint": "La clé personnelle de l'utilisateur (BYOK, connexion ChatGPT ou fournisseur local) a toujours la priorité — la clé du serveur est la dernière étape de la chaîne de fournisseurs.",
"consentHint": "Les requêtes via la clé du serveur nécessitent le consentement IA actif de l'utilisateur ; sans justificatif de consentement, rien n'est envoyé.",
+ "baseUrlHint": "L'URL de base détermine l'API : une URL Anthropic telle que https://api.anthropic.com/v1 est reconnue, tout autre hôte est appelé via l'API compatible OpenAI.",
"statusConfigured": "Configurée",
"statusNotConfigured": "Non configurée",
"keyLabel": "Clé API",
diff --git a/messages/it.json b/messages/it.json
index ee272c0cb..3cc1dd08e 100644
--- a/messages/it.json
+++ b/messages/it.json
@@ -6473,6 +6473,7 @@
"description": "Una chiave dell'operatore per gli account che non ne hanno una propria.",
"byokHint": "La chiave personale dell'utente (BYOK, accesso ChatGPT o provider locale) ha sempre la precedenza — la chiave del server è l'ultimo passo della catena dei provider.",
"consentHint": "Le richieste tramite la chiave del server richiedono il consenso IA attivo dell'utente; senza una ricevuta di consenso non viene inviato nulla.",
+ "baseUrlHint": "L'URL di base determina l'API: un URL Anthropic come https://api.anthropic.com/v1 viene riconosciuto, qualsiasi altro host viene chiamato tramite l'API compatibile con OpenAI.",
"statusConfigured": "Configurata",
"statusNotConfigured": "Non configurata",
"keyLabel": "Chiave API",
diff --git a/messages/ko.json b/messages/ko.json
index ab9e42553..062b3e109 100644
--- a/messages/ko.json
+++ b/messages/ko.json
@@ -6473,6 +6473,7 @@
"description": "자기 키를 설정하지 않은 계정을 위한 운영자 키예요.",
"byokHint": "사용자 본인 키(BYOK, ChatGPT 로그인, 로컬 제공자)가 항상 우선해요 — 서버 키는 제공자 체인의 마지막 단계예요.",
"consentHint": "서버 키로 나가는 요청에는 사용자의 유효한 AI 동의가 필요해요. 동의 기록이 없으면 아무것도 전송하지 않아요.",
+ "baseUrlHint": "기본 URL이 API를 결정합니다. https://api.anthropic.com/v1 같은 Anthropic 주소는 인식되며, 그 밖의 호스트는 OpenAI 호환 API로 호출됩니다.",
"statusConfigured": "설정됨",
"statusNotConfigured": "설정 안 됨",
"keyLabel": "API 키",
diff --git a/messages/pl.json b/messages/pl.json
index b95837dd1..de783600b 100644
--- a/messages/pl.json
+++ b/messages/pl.json
@@ -6473,6 +6473,7 @@
"description": "Klucz operatora dla kont, które nie mają własnego.",
"byokHint": "Własny klucz użytkownika (BYOK, logowanie ChatGPT lub dostawca lokalny) zawsze ma pierwszeństwo — klucz serwera jest ostatnim ogniwem łańcucha dostawców.",
"consentHint": "Żądania przez klucz serwera wymagają aktywnej zgody użytkownika na AI; bez potwierdzenia zgody nic nie jest wysyłane.",
+ "baseUrlHint": "Adres bazowy decyduje o API: adres Anthropic taki jak https://api.anthropic.com/v1 jest rozpoznawany, każdy inny host jest wywoływany przez API zgodne z OpenAI.",
"statusConfigured": "Skonfigurowany",
"statusNotConfigured": "Nieskonfigurowany",
"keyLabel": "Klucz API",
diff --git a/src/components/admin/ai-server-key-section.tsx b/src/components/admin/ai-server-key-section.tsx
index 9fa09b63e..d9f0e6f1f 100644
--- a/src/components/admin/ai-server-key-section.tsx
+++ b/src/components/admin/ai-server-key-section.tsx
@@ -34,6 +34,10 @@ import { PasswordInput } from "./_shared";
* key here never silently forwards anyone's health data.
* - The base URL is locked server-side to HTTPS + a hostname allowlist
* (`ADMIN_AI_BASE_URL_ALLOWLIST` extends it).
+ * - The base URL also picks the wire: an `anthropic.com` host is called on
+ * Anthropic's Messages API, every other host on the OpenAI-compatible one
+ * (`resolveAdminProvider` in `src/lib/ai/provider.ts`). `baseUrlHint` is
+ * that sentence for the operator.
*/
interface AiServerKeyResponse {
@@ -113,6 +117,7 @@ export function AiServerKeySection() {