From e9e594afa70680cb0c0d3ff09e88cb29382a1339 Mon Sep 17 00:00:00 2001
From: Christiaan Arnoldus <christiaan.arnoldus@outlook.com>
Date: Fri, 27 Feb 2026 11:21:13 +0100
Subject: [PATCH] Enable routing to Vercel for Anthropic models

---
 src/lib/providers/anthropic.ts    |  6 +++---
 src/lib/providers/vercel/index.ts | 16 ----------------
 2 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/src/lib/providers/anthropic.ts b/src/lib/providers/anthropic.ts
index aa665b7fc..df9d9f94f 100644
--- a/src/lib/providers/anthropic.ts
+++ b/src/lib/providers/anthropic.ts
@@ -17,9 +17,9 @@ export function isHaikuModel(requestedModel: string) {
 }
 
 function appendAnthropicBetaHeader(extraHeaders: Record<string, string>, betaFlag: string) {
-  extraHeaders['x-anthropic-beta'] = [extraHeaders['x-anthropic-beta'], betaFlag]
-    .filter(Boolean)
-    .join(',');
+  for (const header of ['anthropic-beta', 'x-anthropic-beta']) {
+    extraHeaders[header] = [extraHeaders[header], betaFlag].filter(Boolean).join(',');
+  }
 }
 
 function hasCacheControl(message: OpenAI.ChatCompletionMessageParam) {
diff --git a/src/lib/providers/vercel/index.ts b/src/lib/providers/vercel/index.ts
index 7e15306bc..b97ed04b7 100644
--- a/src/lib/providers/vercel/index.ts
+++ b/src/lib/providers/vercel/index.ts
@@ -1,6 +1,5 @@
 import type { BYOKResult } from '@/lib/byok';
 import { kiloFreeModels, preferredModels } from '@/lib/models';
-import { isAnthropicModel } from '@/lib/providers/anthropic';
 import { getGatewayErrorRate } from '@/lib/providers/gateway-error-rate';
 import {
   AutocompleteUserByokProviderIdSchema,
@@ -71,13 +70,6 @@ export async function shouldRouteToVercel(
     return true;
   }
 
-  if (isAnthropicModel(requestedModel)) {
-    console.debug(
-      `[shouldRouteToVercel] Anthropic models are not routed to Vercel pending fine-grained tool streaming support`
-    );
-    return false;
-  }
-
   if (!preferredModels.includes(requestedModel)) {
     console.debug(`[shouldRouteToVercel] only recommended models are tested for Vercel routing`);
     return false;
@@ -118,14 +110,6 @@ export function applyVercelSettings(
 ) {
   requestToMutate.model = mapModelIdToVercel(requestedModel);
 
-  if (isAnthropicModel(requestedModel)) {
-    // https://vercel.com/docs/ai-gateway/model-variants#anthropic-claude-sonnet-4:-1m-token-context-beta
-    extraHeaders['anthropic-beta'] = [extraHeaders['x-anthropic-beta'], 'context-1m-2025-08-07']
-      .filter(Boolean)
-      .join(',');
-    delete extraHeaders['x-anthropic-beta'];
-  }
-
   if (userByok) {
     if (userByok.length === 0) {
       throw new Error('Invalid state: userByok should be null or not empty');