Twilio MCP server has invalid property key in tool schema

Bug Description

Claude Desktop fails to start any Code session with the Twilio integration enabled. The API returns a 400 error because one of the Twilio MCP tools has an invalid property key in its input schema.

Error Message

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.52.custom.input_schema.properties: Property keys should match pattern '^[a-zA-Z0-9_.-]{1,64}$'"},"request_id":"req_011CXwJpvnPAfwSfJUNQjT5L"}

Environment

• App: Claude Desktop (macOS)
• Feature: Code mode with Twilio integration enabled
• Reproducibility: 100% - happens on every session launch

Root Cause

Tool #52 (0-indexed across all MCP tools) has a property name that contains an invalid character (likely a space, slash, or exceeds 64 chars). The Twilio MCP server auto-generates tools from their OpenAPI spec, and one of those generated tool schemas has a non-compliant property key.

Workaround

Disconnecting the Twilio integration in Claude Desktop Settings → Integrations allows Code sessions to start normally.

Expected Behavior

All MCP tool schemas should have property keys matching the pattern ^[a-zA-Z0-9_.-]{1,64}$ before being sent to the API.