### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

After configuring mcp and starting, when using claude code, an error was reported when viewing the log

``` mcp_servers: xx: ```

### Steps to Reproduce

1. Configure mcp in yaml 2. Start litellm 3. Start claude code

### Relevant log output

```shell LiteLLM: Proxy initialized with Config, Set models: claude-opus-4-8 claude-sonnet-4-8 claude-haiku-4-5-20251001 auto query-engine 393aa359c9ad4a4bb28630fb5613f9c281cde053 INFO: Application startup complete. INFO: Uvicorn running on http://0.0.0.0:4000 (Press CTRL+C to quit) INFO: 127.0.0.1:57284 - "HEAD / HTTP/1.1" 200 OK INFO: 127.0.0.1:57294 - "POST /mcp HTTP/1.1" 307 Temporary Redirect INFO: 127.0.0.1:57292 - "GET /v1/models?limit=1000 HTTP/1.1" 200 OK INFO: 127.0.0.1:57303 - "POST /mcp/ HTTP/1.1" 200 OK INFO: 127.0.0.1:57303 - "POST /mcp HTTP/1.1" 307 Temporary Redirect INFO: 127.0.0.1:57309 - "POST /mcp/ HTTP/1.1" 202 Accepted INFO: 127.0.0.1:57309 - "GET /mcp HTTP/1.1" 307 Temporary Redirect INFO: 127.0.0.1:57310 - "POST /mcp HTTP/1.…