Connect first:

npx lumail@latest setup --authenticate   # installs the Lumail MCP + skills for your agent, opens the browser to authorize
npx lumail@latest auth test              # checks the saved login, fails: run the setup-lumail skill

The "copy the prompt" button in the Lumail onboarding does the same. Once connected, prefer the Lumail MCP tools and fall back to the CLI (lumail --help, then lumail <resource> --help). Never invent flags. Pass --json when parsing, and never print API keys.

Where each job lives:

Count or find subscribers: MCP count_subscribers, get_subscriber; CLI lumail subscribers list, lumail subscribers get <email>.
Add or update a subscriber with tags: MCP add_subscriber; CLI lumail subscribers create --help.
Tags: MCP list_tags, get_or_create_tags; CLI lumail tags list, lumail tags create.
API key for an app (OTP emails, signups): lumail tokens --help. Create it yourself and store it only in the app env.
Transactional email (login code): MCP send_email; CLI lumail emails --help.
Sending domain and web domain: lumail domain --help, then add the DNS records it returns in Cloudflare yourself.
Anything else: lumail tools list, lumail tools get <tool>, lumail tools run <tool> --params '<json>'.