I use Little Snitch and so far I have only seen Claude Code connect to api.anthropic.com and Sentry for telemetry. I have not seen any Vercel connections, but I always turn off telemetry in everything before I run it. If you log in with OAuth2, it also connects to platform.claude.com . For auto updates, it fetches release info from raw.githubusercontent.com and downloads the actual files from storage.googleapis.com. I think it also uses statsig.anthropic.com for stats. One weird thing, I did see it try to connect to app.nucleus.sh once, and I have no idea why.

Here are some environment variables that you’d like to set, if you’re as paranoid as me:

  ANTHROPIC_LOG="debug"
  CLAUDE_CODE_ACCOUNT_UUID="11111111-1111-1111-1111-111111111111"
  CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING="1"
  CLAUDE_CODE_DISABLE_FEEDBACK_SURVEY="1"
  CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC="1"
  CLAUDE_CODE_DISABLE_TERMINAL_TITLE="1"
  CLAUDE_CODE_ENABLE_PROMPT_SUGGESTION="false"
  CLAUDE_CODE_ORGANIZATION_UUID="00000000-0000-0000-0000-000000000000"
  CLAUDE_CODE_USER_EMAIL="root@anthropic.com"
  DISABLE_AUTOUPDATER="1"
  DISABLE_ERROR_REPORTING="1"
  DISABLE_FEEDBACK_COMMAND="1"
  DISABLE_TELEMETRY="1"
  ENABLE_CLAUDEAI_MCP_SERVERS="false"
  IS_DEMO="1"