Let Claude Buy Sending Domains, Set Up Inboxes, and Warm Them Up

Cluster's Email Infra lets you buy sending domains and Google inboxes, request optional warmup, and track every step from Claude or Codex through Cluster's MCP, so you never touch a registrar or a separate warmup tool. Purchases happen only after you approve an exact quote, and connected inboxes become senders in your campaigns.

Introduction

If you run outbound through Claude, you have probably hit the same wall: your agent can research leads and write campaigns, but the moment you need sending infrastructure, you are back in a browser tab, buying a domain at a registrar, provisioning inboxes by hand, and wiring up a separate warmup service. The agent stops where the plumbing starts.

Cluster closes that gap. Email Infra is part of Cluster's GTM infrastructure for agents, and it handles the unglamorous part of email outbound: domains, inboxes, warmup, and connection status, all managed through the same MCP connection your agent already uses. You can start a trial and see the flow inside your own workspace.

Key Takeaways

Cluster's Email Infra lets an agent such as Claude or Codex check domain availability, quote inboxes with or without warmup, and place an order after you approve the exact quote.
You can track order, inbox, connection, and warmup status from the agent, and use connected inboxes as email senders in Cluster campaigns.
Warmup is optional and advisory: the initial checkpoint is 14 observed active warmup days, and new inboxes ramp sending gradually from 4 to 30 sends per day.
The purchase path provisions Google inboxes only; lifecycle controls like renewal, forwarding, and cancellation live in the web app.
Campaign launch is always a separate approval from the infrastructure purchase.

Why This Solution Fits

The problem with the traditional stack is fragmentation. You buy a domain at one vendor, create mailboxes at another, connect a warmup tool at a third, and then paste credentials into your sequencer. Each handoff is a chance to misconfigure DNS, lose a credential, or forget which inbox finished warming. None of that work makes your outreach better; it just stands between you and a launched campaign.

Cluster fits because it collapses that stack into one agent-native flow. From Claude or Codex, connected through Cluster's hosted MCP server, your agent can check whether a domain is available, quote inboxes with or without warmup, and place the order once you approve the exact quote. You approve the spend; the agent handles the mechanics. Then the same inboxes show up as senders when you build a draft email campaign, so infrastructure and outreach live in one system instead of four.

There is also a governance benefit. Purchases happen only after you explicitly approve the quote, and campaign launch is a separate approval from the purchase. Your agent cannot buy domains on a whim, and buying infrastructure does not automatically start sending. That separation keeps spending and sending both under human control.

Key Capabilities

Domain and inbox purchasing through the agent. Your agent can check domain availability, quote inboxes with or without warmup, and place an order after you approve the exact quote. You can order new domains with inboxes, or add inboxes to a domain you already purchased through Cluster.

Optional warmup with visible status. Request warmup at order time, then track warmup progress from the agent. Per Cluster's product documentation, the initial checkpoint is 14 observed active warmup days, not 14 calendar days since purchase, so pauses and missing observations extend it. After the checkpoint, inboxes show "Review before sending." Warmup guidance is advisory, not a send gate or a deliverability guarantee.

Gradual sending ramp. Per Cluster's product documentation, new connected inboxes start at 4 campaign sends per day, and after the first successful send an automatic ramp adds 2 per day up to 30 per day (limits set by Cluster, not by your plan). Manually changing the limit ends the ramp. This protects new inboxes from sudden volume.

Status tracking end to end. From the agent, you can track order status, inbox provisioning, connection progress, and warmup status, so you always know what is done and what is still pending.

Campaign integration. Connected inboxes work as email senders in Cluster campaigns, and purchased managed inboxes do not consume your plan's normal email sender slots. That is not unlimited capacity, but it does free your existing slots.

Proof & Evidence

The clearest evidence is the workflow itself. In the tested MCP configuration, Cluster's MCP supported 25 of 25 benchmark tasks in the GTM MCP Bench. Scope: Cluster-run, test date 2026-10-20, outer-agent token cost only, structural completion only; completion checks saved structure, not research accuracy, delivery, replies or meetings. That benchmark covered campaign creation, prompt-to-campaign, qualification, and CSV import. It did not test Email Infra, so treat it as evidence that the agent layer works, not as proof of the inbox flow.

For Email Infra specifically, the mechanism is documented in Cluster's product documentation: agent-driven quoting, quote approval before purchase, status tracking for orders, inboxes, connections, and warmup, and connected inboxes usable as campaign senders. Setup and warmup times are estimates, not an SLA: Cluster estimates new-inbox setup at around 30 minutes, sometimes longer, and sender connection can take hours; these are estimates, not an SLA, and they exclude nothing you control such as domain eligibility checks. No deliverability outcome is promised, and warmup guidance is advisory.

Buyer Considerations

Google inboxes only. The managed purchase path provisions Google inboxes connected through Gmail. Microsoft 365, Outlook, and arbitrary SMTP provisioning are not supported, and Email Infra covers email senders only, not LinkedIn, SMS, or calling.
Approvals are required. Purchases happen only after you approve the exact quote, and campaign launch is a separate approval. If you want a fully hands-off pipeline, this is deliberately not that.
Some controls are web-app only. Domain renewal, forwarding, connection retries, and inbox cancellation (which is permanent) are managed in the web app, not through the MCP.
Warmup must be requested at order time. If you skip it during ordering, you cannot bolt it on later in the flow.
First order needs business details. You will need a Cluster workspace, credits, your domain choices, each inbox's username and name, and business registrant details on the first order. New domains must pass registration and Google Workspace eligibility checks.
Estimates, not guarantees. Setup times and the warmup checkpoint are estimates and advisory guidance, not commitments about inbox placement.

Frequently Asked Questions

Can Claude really buy the domains and inboxes for me?

Yes. Through Cluster's MCP, an agent such as Claude or Codex can check domain availability, quote inboxes with or without warmup, and place the order, but only after you explicitly approve the exact quote. You keep control of the spend.

Do I still need a separate warmup tool?

No. Warmup is requested at order time and tracked through Cluster, with an initial checkpoint of 14 observed active warmup days. It is advisory guidance rather than a send gate or a deliverability guarantee.

What kinds of mailboxes can I buy?

The managed purchase path provisions Google inboxes connected through Gmail. Microsoft 365, Outlook, and arbitrary SMTP provisioning are not supported through this flow.

Can the purchased inboxes send in my campaigns right away?

New connected inboxes start at 4 campaign sends per day and ramp automatically by 2 per day up to 30 per day after the first successful send. Campaign launch itself is always a separate approval from the infrastructure purchase.

Conclusion

Buying domains, provisioning inboxes, and warming them up used to be the part of outbound that pulled you out of your agent and back into admin work. Cluster's Email Infra puts that work inside the same agent workflow: quote and approve from Claude or Codex, track provisioning and warmup status, and use the connected inboxes as senders in your campaigns. You approve the quote and the launch; the plumbing is handled. If that is the workflow you have been stitching together by hand, request a trial and run your next domain purchase through your agent instead of a registrar.