[Docs] Update MCP authentication from headers to query parameters

Author: joaquim-verges

apps/portal/src/app/ai/mcp/page.mdx

@@ -7,14 +7,11 @@ You can use the thirdweb MCP server to interact with the thirdweb API from your
 You can access the MCP server at the following url, with your project secret key.
 
 ```http
-# endpoint
-POST /mcp
-Host: api.thirdweb.com
-
-# auth header (required)
-x-secret-key <your-project-secret-key>
+POST https://api.thirdweb.com/mcp?secretKey=<your-project-secret-key>
 ```
 
+Make sure to keep your secret key safe and never share it with anyone.
+
 ### Usage with LLM clients
 
 You can also use the MCP server on your own LLM client, like cursor, claude code and more. Refer to your LLM client's documentation for more information.
@@ -27,10 +24,7 @@ Add the following to your `.cursor/mcp.json` file:
 {
   "mcpServers": {
     "thirdweb-api": {
-      "url": "https://api.thirdweb.com/mcp",
-      "headers": {
-        "x-secret-key": "<your-project-secret-key>"
-      }
+      "url": "https://api.thirdweb.com/mcp?secretKey=<your-project-secret-key>",
     }
   }
 }
@@ -50,10 +44,7 @@ client = MultiServerMCPClient(
     {
         "thirdweb-api": {
             "transport": "streamable_http",
-            "url": "https://api.thirdweb.com/mcp",
-            "headers": {
-                "x-secret-key": "<your-project-secret-key>"
-            },
+            "url": "https://api.thirdweb.com/mcp?secretKey=<your-project-secret-key>",
         }
     }
 )