Restrict MCP tool names

[Azquelt]

MCP version 2025-11-24 adds new guidance for tool names.

• Tool names SHOULD be between 1 and 128 characters in length (inclusive).
• Tool names SHOULD be considered case-sensitive.
  • The following SHOULD be the only allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits (0-9), underscore (_), hyphen (-), and dot (.)
  • Tool names SHOULD NOT contain spaces, commas, or other special characters.
  • Tool names SHOULD be unique within a server.
• Example valid tool names:
  • getUser
  • DATA_EXPORT_v2
  • admin.tools.list

Although the spec lists these as "SHOULD", we will enforce all of these restrictions. (It's much easier to remove restrictions later if there's a good reason for it than it is to add restrictions later which break existing code.)