diff --git a/src/proxy/anthropic.ts b/src/proxy/anthropic.ts
index 668b99f..5b9c4be 100644
--- a/src/proxy/anthropic.ts
+++ b/src/proxy/anthropic.ts
@@ -206,8 +206,10 @@ function setAnthropicBetaHeader(req: Request) {
  */
 function addWebSearchTool(req: Request) {
   // Check if this is a Claude model that supports web search and if web search is enabled
-  const supportsWebSearch = /^claude-3-(5|7)/.test(req.body.model);
-  const useWebSearch = supportsWebSearch && Boolean(req.body.enable_web_search);
+  const isClaude35 = req.body.model?.includes("claude-3-5") || req.body.model?.includes("claude-3.5");
+  const isClaude37 = req.body.model?.includes("claude-3-7") || req.body.model?.includes("claude-3.7");
+  const isClaude4 = req.body.model?.includes("claude-4");
+  const useWebSearch = (isClaude35 || isClaude37 || isClaude4) && Boolean(req.body.enable_web_search);
   
   if (useWebSearch) {
     // Create the base web search tool
@@ -305,7 +307,7 @@ const textToChatPreprocessor = createPreprocessorMiddleware(
  * (claude-3 based models do not support the old text completion endpoint).
  */
 const preprocessAnthropicTextRequest: RequestHandler = (req, res, next) => {
-  if (req.body.model?.startsWith("claude-3")) {
+  if (req.body.model?.startsWith("claude-3") || req.body.model?.startsWith("claude-4")) {
     textToChatPreprocessor(req, res, next);
   } else {
     nativeTextPreprocessor(req, res, next);
@@ -336,7 +338,9 @@ const oaiToChatPreprocessor = createPreprocessorMiddleware(
  */
 const preprocessOpenAICompatRequest: RequestHandler = (req, res, next) => {
   maybeReassignModel(req);
-  if (req.body.model?.includes("claude-3")) {
+  const model = req.body.model;
+  const isClaude4 = model?.includes("claude-4");
+  if (model?.includes("claude-3") || isClaude4) {
     oaiToChatPreprocessor(req, res, next);
   } else {
     oaiToTextPreprocessor(req, res, next);