diff --git a/packages/ai/src/route/client.ts b/packages/ai/src/route/client.ts
index 7addb1a0426..52ba6bbdd36 100644
--- a/packages/ai/src/route/client.ts
+++ b/packages/ai/src/route/client.ts
@@ -132,7 +132,7 @@ const makeRouteLanguageModel = <Options extends ProviderOptions, Compact extends
 ) => {
   const provider = route.provider ?? ("provider" in mapped ? mapped.provider : undefined)
   if (!provider) throw new Error(`Route.model(${route.id}) requires a provider`)
-  if (!endpointBaseURL(route.endpoint))
+  if (!route.endpoint.baseURL)
     throw new ProviderConfigurationError({
       provider: ProviderID.make(provider),
       message: `Route.model(${route.id}) requires an endpoint baseURL — configure it on the route first`,
@@ -160,9 +160,6 @@ const mergeRouteDefaults = (base: RouteDefaults | undefined, patch: RouteDefault
   }
 }
 
-const endpointBaseURL = <Body>(endpoint: Endpoint.Definition<Body>) =>
-  typeof endpoint.baseURL === "string" ? endpoint.baseURL : undefined
-
 const mergeHeaders = (...items: ReadonlyArray<Record<string, string> | undefined>) => {
   const entries = items.flatMap((item) =>
     item === undefined ? [] : Object.entries(item).filter((entry): entry is [string, string] => entry[1] !== undefined),
diff --git a/packages/core/src/session/model-request.ts b/packages/core/src/session/model-request.ts
index 15c7949ade4..238f67ae8bb 100644
--- a/packages/core/src/session/model-request.ts
+++ b/packages/core/src/session/model-request.ts
@@ -304,7 +304,7 @@ export const layer = Layer.effect(
       const baseURL = base.model.route.endpoint.baseURL
       const modelHook = yield* hooks.trigger("session", "model.request", {
         ...scope,
-        baseURL: typeof baseURL === "string" ? baseURL : undefined,
+        baseURL,
         headers: { ...base.http?.headers },
       })
       const route =