[BUG] Claude stops working when I add XcodeBuildMCP to my config

Environment

• Platform (select one):
• [ ] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [X] Other: Claude Code
• Claude CLI version: 0.2.76 (Claude Code)
• Operating System: macOS 14.6
• Terminal: <!-- e.g. iTerm2, Terminal App -->

Bug Description

I installed XcodeBuildMCP, an MCP server to build and work with iOS/macOS Xcode projects. The MCP works just fine in Cursor and Claude desktop but appears to break Claude Code.

Steps to Reproduce

1. Install XcodeBuildMCP
2. Add it to claude code via claude mcp add <...>
3. Launch claude code and send any message, they all result in the following error:

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.46.custom.name: String should have at most 64 characters"}}

Additional Context

XcodeBuildMCP only offers 39 tools so I'm not sure what "tools.46" refers too. All of its tools' names are under 64 character. I first reported the issue to their repo, but it definitely seems like it's an issue with Claude Code since the MCP works just fine in other platforms.