Categories › Business & Finance › Marketing, ads & analytics
Read-only deliverability + strategy: free cold email checks, list tools, inbox planning, research.
Remote server: your requests and data go to warminboxes.com. Claude Code: claude mcp add --transport http warminboxes-free-mcp https://warminboxes.com/mcp · Claude app: Settings → Connectors → Add custom connector.
The tools this server listed when we connected to it, in its own words.
check_deliverability — Grade a domain A-F for cold email readiness. Checks SPF, DKIM, DMARC, MX, blacklists and domain age together and returns a weighted score wicheck_spf — Look up a domain's SPF record and validate it, including the recursive DNS lookup count that silently breaks SPF past 10.check_dkim — Find and validate a domain's DKIM signing key, including key strength. Leave selector empty to auto-scan 26 common selectors (google, selectcheck_dmarc — Look up and parse a domain's DMARC record: policy, subdomain policy, percentage, alignment and reporting tags, each explained. p=none (monitcheck_bimi — Validate a domain's BIMI record, the logo SVG, the VMC, and the DMARC enforcement level Gmail requires before it will show a brand logo.check_mta_sts — Validate a domain's _mta-sts DNS record and its published policy file: mode, MX patterns, max_age and TLS-RPT.check_ssl — Read a host's TLS certificate: issuer, validity dates and days remaining, subject alternative names, key type and size, signature algorithm,check_dns — Query any DNS record type for a domain: MX, TXT, A, AAAA, CNAME, NS, SOA, CAA.lookup_txt — Every TXT record on a domain, with each one identified (SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI, or which service's ownership token it is),check_rdns — The PTR record for an IPv4 or IPv6 address, and the forward lookup that decides whether it counts. Reverse DNS is delegated to whoever holdscheck_blacklist — Check a domain or IP against 20+ major email blacklists (Spamhaus, Barracuda, SORBS and others) and report which list it appears on.check_surbl — Check domains against the SURBL URI blacklist in bulk. URI blacklists list the domains that appear inside a message body, so a listed trackicheck_nameservers — Get the NS records and the DNS provider behind one domain or a whole list. Useful for working out who actually controls a domain's DNS beforcheck_domain_expiry — Get a domain's registrar, creation date, expiry date and days remaining, over RDAP with a WHOIS fallback for ccTLDs that publish no RDAP sercheck_google_domain — Tell whether a domain is already attached to a Google Workspace account, or is clear for a fresh Google tenant.check_cname — Follow a host's full CNAME chain and flag the mistakes that break a cold-email tracking domain. Pass expected to assert where the chain shouverify_email — Check email addresses for syntax, live MX records, disposable providers and role prefixes (info@, sales@). Does not open SMTP connections, slookup_mx — Look up a domain's MX records with priorities and resolved IPs, and identify the mailbox provider (Google Workspace, Microsoft 365, Zoho, Fasegment_esp — Split a list of domains by the email provider behind them (Google, Microsoft, a security gateway, or another provider) from their MX recordsplan_from_list — Estimates a sending fleet for a recipient list. Looks up the MX records of up to 100 recipient domains (or addresses) to measure the provideplan_infrastructure — Estimates how many inboxes and domains a daily cold email volume needs and the monthly cost at WarmInboxes' published prices. Inputs: emailsquote_inboxes — Prices a given number of inboxes at WarmInboxes' published prices: the domains (or Azure tenants) they sit on, daily sending capacity at theget_diagnostic_playbook — Returns WarmInboxes' diagnostic playbook for a cold email problem: the questions to ask the person, the checks to run in order from cheapestexpand_spintax — Expand a spintax template such as "{Hi|Hey} there" and render its Liquid merge tags, returning the total number of variations, every variablgenerate_unsubscribe — Build a CAN-SPAM and GDPR compliant opt-out footer in plain text and HTML, with a checklist saying which compliance requirements the detailscheck_email_authentication — SPF, DKIM, DMARC, MX, BIMI and MTA-STS for one domain in one call, each judged pass, weak, fail or not set, with the essentials separated frcheck_domain_reputation — For "this domain used to land and now it does not". Checks the domain against SURBL, its authentication, its age and the address its websitecheck_tracking_domain — Check the domain a campaign's tracked links point at: whether it resolves, serves a valid certificate, is listed on SURBL, sits on a listed check_bulk_sender_requirements — The bulk sender requirements, sorted honestly: SPF, DKIM, DMARC and MX checked from DNS; forward and reverse DNS when given the sending IP; analyze_headers — Read a received message's raw headers. Returns the SPF, DKIM and DMARC verdicts the receiver recorded, which domains authenticated and whethanalyze_email_html — Read an email's HTML. Returns its size against Gmail's ~102 KB clipping limit with what is taking the room, every link and image host, trackanalyze_dmarc_report — Read DMARC aggregate (rua) reports and say who is sending as the domain and what fails: messages passing and failing, failures that are aliganalyze_cold_email — Score a cold email's copy 0-100 for spam risk before it is sent: weighted trigger words by category and severity (subject hits weigh extra),audit_campaign — Audit a cold email campaign before launch: the lead CSV and the sequence checked together for merge tags with no column or empty values, varanalyze_bounces — Classify bounce messages (NDRs): invalid address, full or disabled mailbox, reputation block, authentication failure, throttling, content blanalyze_microsoft_headers — Read the spam verdict Microsoft 365 or Outlook stamped on a delivered message: SCL (spam confidence), BCL (bulk), PCL, SFV, the category, anpreview_inbox — Show how a cold email's sender name, subject line and preview text are cut off in Gmail desktop, Gmail mobile and Outlook, with warnings (nogenerate_dns_records — Write an SPF record from the providers that send for a domain (with an estimate of its DNS lookups against the limit of 10), a DMARC record plan_rotation — Builds a warm rotation, WarmInboxes' method: the inboxes split into Batch 1 and Batch 2, both tagged in the sequencer and added to the campaplan_verification_waterfall — Price an email verification waterfall: the list run through verifiers in sequence with unknowns passed down the chain, every order compared,Not tested by KitScout yet. When our harness runs it, pros, cons and the tasks we tried appear here, with the date and evidence.