WarmInboxes Free MCP: Fleet Planner MCP Server

Estimates a sending fleet for a recipient list. Looks up the MX records of up to 100 recipient domains (or addresses) to measure the provider mix, then sizes a Google Workspace pool for the Google-hosted recipients and an Azure pool for everyone else (Microsoft 365, other providers and gateway-protected domains, with a warning for gateways); microsoftEsp: "microsoft" moves the Microsoft recipients to a Microsoft 365 pool, only when the person asks for it. Returns inbox count, domain count, per-inbox pace and monthly cost for each pool, plus totals, the routing rule and the placement-log figures behind it. Domains with no mail server are left out and named. For a longer list, send a sample: the estimate follows the provider split, not the list length. Assumes no reserve capacity. A planning estimate only: it does not provision or order anything. The result describes how an order is placed: a first order in the WarmInboxes app, later ones through WarmInboxes Infrastructure MCP.

Estimates how many inboxes and domains a daily cold email volume needs and the monthly cost at WarmInboxes' published prices. Inputs: emailsPerDay; optionally the provider (esp), prewarmed or fresh, billing cycle, emails per inbox per day and inboxes per domain. With currentInboxes (healthy inboxes already sending) it sizes only the shortfall between their capacity and the target, and says when nothing needs adding; with reservePercent it adds that much spare capacity on top, and only when asked: no reserve is recommended by default. With dealValue (and optionally closeRate and positiveRate) it adds a revenue and ROI projection from those inputs. Assumes the provider's default daily pace per inbox unless emailsPerMailbox is given, and 22 sending days a month. The result is a planning estimate: it orders nothing, does not guarantee placement or replies, and its revenue figures follow only from the rates supplied.

Builds a warm rotation, WarmInboxes' method: the inboxes split into Batch 1 and Batch 2, both tagged in the sequencer and added to the campaign, the active batch at full daily limits while the resting batch sends follow-ups only, swapped by changing the limits on each tag. The swap cycle follows the sequence length (sequenceDays: up to 7 days weekly, up to 14 every two weeks, longer monthly). Returns batch sizes, the cycle and why, the setup steps, how to rotate lead lists between the batches, the daily load per active inbox against a 15-a-day pace, how many inboxes the volume needs, and an eight-week calendar. Use it for anyone asking how to rotate inboxes, keep inboxes and domains alive longer, or send into saturated niches such as ecommerce, SaaS or healthcare. A suggested plan only: it changes no inbox or sequencer.

Price an email verification waterfall: the list run through verifiers in sequence with unknowns passed down the chain, every order compared, cheapest cost per usable email first. Uses typical figures for three verifiers unless you pass your own prices and resolve rates (POST JSON for verifiers).

Rename a lead CSV's columns to the fields a sequencer imports (Instantly, Smartlead, EmailBison, or generic snake_case). Every row and column is kept; only the header changes, and columns with no standard field keep a snake_case name for custom variables. Returns the mapping, and the converted CSV when it is 500 rows or fewer.

Returns WarmInboxes' diagnostic playbook for a cold email problem: the questions to ask the person, the checks to run in order from cheapest to most expensive (with the tool for each), what WarmInboxes' published studies measured a finding to cost (for example that a SURBL listing left reply rate flat, while Google's domain-reputation refusal cost about 43% of replies), the guides and studies to read with full URLs, the evidence that would make new domains or inboxes the right fix, and WarmInboxes' operator notes that bear on it. Give a symptom in the person's words, or a scenario id; with neither it lists the scenarios. Runs no check on any domain.

Get a domain's registrar, creation date, expiry date and days remaining, over RDAP with a WHOIS fallback for ccTLDs that publish no RDAP service. Domain age is useful context when diagnosing deliverability, read alongside the provider, reputation and sending history; no published WarmInboxes study isolates its effect.

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 from a policy, and where a provider publishes DKIM. Returns host, type and value to publish. It writes records; to check what is published, use check_spf, check_dmarc and check_dkim.

Tell whether a domain is already attached to a Google Workspace account, or is clear for a fresh Google tenant.

Look up a domain's MX records with priorities and resolved IPs, and identify the mailbox provider (Google Workspace, Microsoft 365, Zoho, Fastmail and others) and any security gateway in front of it (Mimecast, Proofpoint, Barracuda and others). Pass `domains` instead of `domain` for up to 100 at once, which also returns a provider breakdown. Reports a null MX (RFC 7505) rather than treating it as a broken record, and does not guess the provider behind a gateway, because that is not observable from the MX.

The WarmInboxes price list as data: prewarmed and fresh inboxes on Google Workspace, Microsoft 365 and Azure, every billing cycle, the safe daily send pace per inbox, and delivery time. For a costed fleet for a volume, use plan_infrastructure.

Prices a given number of inboxes at WarmInboxes' published prices: the domains (or Azure tenants) they sit on, daily sending capacity at the provider's pace, monthly cost and delivery time. Use it when the person already knows the count ("preview 100 inboxes"); for a send volume use plan_infrastructure. Azure is sold by the tenant, so a count that does not fill one is quoted for the tenants it needs, with a note. A quote only: it orders nothing, and the exact preview with real domain and mailbox names is in the app or on WarmInboxes Infrastructure MCP.

Read a WarmInboxes operator note, guide, study, playbook, dataset, recipe, comparison or changelog entry in full, as markdown. Long pages come in parts split at headings: the first call says how many, and nextPart gives the one to ask for. Datasets also return their data as JSON. Use the url find_resources gave you.

Search what WarmInboxes publishes: operator notes (WarmInboxes' rules from running fleets, with the research behind them), cold email guides, deliverability playbooks, original studies and their datasets, costed infrastructure recipes, tool demo videos, inbox guides per sequencer and AI agent, provider comparisons, Claude skills, the changelog, the product pages (the ChatGPT plugin, the Claude connector, the MCP servers, the platform features, each with its current status), and the offer and about pages. Searches titles and full text, and each match carries the passage that best answers the query. It holds WarmInboxes' own studies as well as guides: 5 published studies, each with a stable WI-RESEARCH ID; type "study" lists every one, and https://warminboxes.com/research.json is the index. read_resource returns a whole page.

Split a list of domains by the email provider behind them (Google, Microsoft, a security gateway, or another provider) from their MX records. WarmInboxes routes Google-hosted recipients to Google Workspace inboxes and everyone else to Azure; plan_from_list sizes that split.

Find the WarmInboxes free tool for a task ("check my email headers", "clean a CSV", "will this land in spam") and say how to use it: the MCP tool to call here, or the page to send the person to when it runs only in the browser. Call with no task to list every tool.