diff --git a/mcp-client-python/client.py b/mcp-client-python/client.py
index 5424fbd..c53b39b 100644
--- a/mcp-client-python/client.py
+++ b/mcp-client-python/client.py
@@ -64,7 +64,7 @@ class MCPClient:
 
         # Initial Claude API call
         response = self.anthropic.messages.create(
-            model="claude-3-7-sonnet-latest",
+            model="claude-sonnet-4-0",
             max_tokens=1000,
             messages=messages,
             tools=available_tools
@@ -97,7 +97,7 @@ class MCPClient:
 
                 # Get next response from Claude
                 response = self.anthropic.messages.create(
-                    model="claude-3-7-sonnet-latest",
+                    model="claude-sonnet-4-0",
                     max_tokens=1000,
                     messages=messages,
                 )
diff --git a/mcp-client-typescript/index.ts b/mcp-client-typescript/index.ts
index d088594..866fa8a 100644
--- a/mcp-client-typescript/index.ts
+++ b/mcp-client-typescript/index.ts
@@ -92,7 +92,7 @@ class MCPClient {
 
     // Initial Claude API call
     const response = await this.anthropic.messages.create({
-      model: "claude-3-7-sonnet-latest",
+      model: "claude-sonnet-4-0",
       max_tokens: 1000,
       messages,
       tools: this.tools,
@@ -127,7 +127,7 @@ class MCPClient {
 
         // Get next response from Claude
         const response = await this.anthropic.messages.create({
-          model: "claude-3-7-sonnet-latest",
+          model: "claude-sonnet-4-0",
           max_tokens: 1000,
           messages,
         });