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Brew is the AI-native ESP. Define your brand once, ship on-brand email in minutes.
Brew is the AI-native ESP. Define your brand once, ship on-brand email in minutes.
Compare MCP support for email campaigns, automations, analytics, and approvals across Brew, Loops, Klaviyo, Customer.io, and other platforms.
Brew publishes this comparison. We reviewed the linked product documentation on September 28, 2026; this is a documentation comparison, not a claim of hands-on testing of every platform. Check current plan limits on the vendor's pricing page.
You connect your email platform's MCP server to Claude and ask for a win-back automation. Claude pulls last month's campaign report without trouble, but nothing in the tool list creates an automation, so you build the flow by hand in the dashboard.
A lot of email platforms now say they "support MCP," but what that means varies. On some platforms an agent can read reports. On others it can build a draft. On a few it can create an automation, publish it and send a campaign to your list.
This guide compares nine email platforms by what their MCP servers let an agent do, then walks through connecting Brew to Claude Code.
We read each vendor's MCP documentation on September 28, 2026 and compared them on four questions:
We did not run the same task through each server. We only mark a tool as able to do something if its own documentation describes it.
| Platform | Campaigns | Automations | Analytics | Auth and guardrails |
|---|---|---|---|---|
| Brew | Create, edit, test, send, schedule | Create triggers and graphs, test, publish, fire | Campaign and automation reports | OAuth or API key; sends pause for confirmation on OAuth and organization connections |
| Klaviyo | Create, send (send_campaign) |
Flow tools | Reporting tools | OAuth or private API key |
| Customer.io | Create, update, delete via the Journeys API | Campaigns (Customer.io's name for automations) | Delivery metrics readable | Read-only by default; live data protected unless an admin enables it |
| HubSpot | Drafts; changelog adds send setup, scheduling and publishing | Not covered in the pages we read | Post-send email analytics | OAuth with PKCE through an MCP auth app |
| Brevo | Create and manage | Not listed | Campaign analytics | MCP key as a Bearer token |
| Loops | Create and manage | Create and manage workflows | Not listed | OAuth |
| Sequenzy | Draft, edit, schedule | Build sequences | Campaign and sequence metrics | OAuth remote server or local API key |
| Resend | Broadcasts | Automations | Logs and metrics | API key |
| Mailchimp | Claude connector builds and launches campaigns; a separate MCP server sends Transactional (Mandrill) email | Check the connector's tool list | Campaign data through the Claude connector | Connector sign-in; Transactional server uses an API key with the AI Agents permission group |
Brew's server is at https://brew.new/api/mcp. You connect with OAuth, choosing one brand or your whole organization, or with an API key. The tool catalog has tools in five groups:
create_email, edit_email, import_email (HTML, MJML, React Email or a Figma frame) and export_email to a connected ESP.send_email for tests and campaigns. It takes a scheduledAt value for scheduled sends. control_email_send pauses, resumes or cancels a send.save_trigger, save_automation, test_automation, fire_trigger_event and list_automation_runs.create_audience, search_contacts, get_email_analytics, and list_automations with performance data.test_email_rendering, create_inbox_placement_test and get_domain_health.Brew's agent recipe recommends reviewing irreversible sends. OAuth and organization connections require confirmation before a live send_email; brand API-key clients need their own approval policy. Brew is also the sending platform, so the agent works with the same domains, audiences and suppression lists your team uses.
Brew is email only. It has no SMS or push channels.
Klaviyo's MCP server connects over OAuth or a private API key, either as a hosted remote server or locally. Its tool list covers campaigns, flows, templates, reporting, profiles, catalogs and more. It includes a send_campaign tool that sends a campaign to its configured audience.
Klaviyo's Claude announcement focuses on reporting, flow audits and briefs. Klaviyo fits ecommerce teams whose customer and order data already live there.
Customer.io's MCP server has US and EU endpoints and gives the agent access to the Journeys UI API and the Data Pipelines API. It exposes separate tools for reads (cio_read_api), writes (cio_write_api) and deletes (cio_delete_api), so you can approve each kind of action separately.
A new connection gets read scope only, and it cannot edit live data or delete people unless an admin enables that. Customer.io is multi-channel, so the same connection can reach SMS, push and in-app messages. It suits teams that already model their product data in Customer.io.
HubSpot's remote server runs at mcp.hubspot.com. You create an MCP auth app inside HubSpot, then connect any client that supports OAuth with PKCE. The setup documentation covers marketing email drafts through manage_marketing_email, along with CRM records. HubSpot's Fall 2026 changelog, dated September 15, 2026, adds send configuration, scheduling, publishing and post-send analytics for marketing email.
It fits teams whose CRM and marketing email both already live in HubSpot.
Brevo's MCP server combines 27 modules behind one endpoint and generates its tools from the Brevo OpenAPI spec. It covers email campaigns, contacts, CRM deals, SMS and WhatsApp campaigns, transactional templates and campaign analytics. You authenticate with a dedicated MCP key.
The Loops MCP server at https://mcp.loops.so manages contacts and mailing lists and sends events and published transactional emails. It also creates and manages campaigns and workflows, and it can edit email content. The docs do not list analytics. Loops fits SaaS teams that want a simple platform their agent can manage over MCP.
Sequenzy's MCP covers subscribers, lists and segments. It also drafts, edits and schedules campaigns, builds sequences with branches and wait-for-event steps, generates AI content and reads analytics. Sequenzy's docs note that some setup, billing, destructive actions and final send decisions may still need the dashboard or a human review.
Resend's agent tooling includes a hosted MCP server at mcp.resend.com/mcp, which you authenticate with an API key. It covers sending, contacts, broadcasts, automations and templates. Resend's Automations became generally available in April 2026. It suits developer teams that already send transactional email through Resend.
Mailchimp has two entry points for agents. Its official MCP server is for Mailchimp Transactional, the product formerly called Mandrill. A separate Claude connector works from your Mailchimp data, and Mailchimp's page describes building, refining and launching campaigns from the conversation. Check the connector's current tool list for exactly what it can save, schedule or send.
| If your agent needs to... | Look at |
|---|---|
| Design an on-brand email, test it and send or schedule it | Brew |
| Build and publish an event-triggered automation | Brew, Loops, Resend, Sequenzy |
| Report on ecommerce campaigns and flows | Klaviyo |
| Work across email, SMS and push with separate read and write approval | Customer.io |
| Stay inside your CRM | HubSpot |
Before you give an agent write access, brief it the way you would brief a new coordinator, and send the first campaign to a seed list before the real audience.
Add Brew's hosted server using Claude Code's HTTP MCP setup:
claude mcp add --transport http brew https://brew.new/api/mcpOpen Claude Code, run /mcp, and authenticate the Brew connection. Select the brand you intend to use. Ask Claude to call get_brew_capabilities before campaign work so it reads the current tool contract.
Start with a draft and a test recipient:
Create a product-update email for the connected brand about our new CSV import.
Link the main button to https://example.com/import.
Show me the draft, subject, sender domain, and audience before scheduling.
Send a test only to my approved test address after I provide it.Review the preview and links, then inspect the test in your inbox. For the live send, give Claude the saved audience, exact date, time, and time zone. Review the confirmation details before approval. Save the returned send ID so you can check status or cancel the scheduled send with control_email_send.
For repeatable backend jobs, use a typed API client or CLI. Keep credentials in the client configuration or environment, not in prompts or committed files.
Brew's CLI guide covers terminal workflows. The MCP versus REST guide explains how to split interactive campaign work from production event handling.
It is an endpoint that exposes a platform's actions as tools an AI assistant can call. Claude, ChatGPT and Cursor are common clients. The assistant reads the tool list and decides which tool to call for your request.
It depends on the platform and your client settings. Brew requires confirmation for live sends on OAuth and organization connections. Brand API-key clients need their own approval policy. Customer.io starts read-only. Other servers rely on your MCP client to ask before each tool call, so check both sides.
Usually not. Brew, Loops, Klaviyo and HubSpot support OAuth, so you paste a server URL and sign in. API keys are the fallback for clients without an OAuth screen.
No. Mailbox providers score your domain and complaint rate. Gmail's sender requirements and CAN-SPAM apply however a send was started.
The Brew MCP page has the server URL and client setup. Connect it, then ask for your next campaign as a test send.
