Bundled execution of the Email deliverability workflow — Diagnose why a domain's email lands in spam: SPF posture, DMARC policy, DKIM key strength, MX targets, and a composite 0–100 score. One x402 payment runs 6 underlying tools (spf-check, dmarc-check, dkim-lookup, email-deliverability, email-validate, dns-lookup); partial-success per step.