MailSlurp guide agent setup

Title: How to Sign Up for MailSlurp and Set Up Your First API Workflow
Description: Step-by-step MailSlurp sign-up guide for developers and QA teams, including email verification, API key setup, and first-run checks.
Canonical URL: https://www.mailslurp.com/guides/signing-up/
Markdown URL: https://www.mailslurp.com/guides/signing-up.md

Use the Markdown URL as the primary plain-text context for this guide. Keep MailSlurp terminology, setup steps, screenshots, and provider-specific instructions intact, and prefer the canonical URL when citing this page.