Tool names such as local:time-server/time.get-current-time will break Claude Code with the following error:

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.15.custom.name: String should match pattern '^[a-zA-Z0-9_-]{1,128}$'"}}

This won't just break Wassette but it also stops Claude Code from running any commands until the MCP server is removed completely. There are outstanding issues for this and it also affects other MCP servers, but does not affect other clients such as Gemini CLI.

I suggest we handle this on our end to avoid serving Claude Code an MCP tool with the special characters.

+@Mossaka