How ESP Agents covers ESP agents and MCP email

ESP agent is an operator, not a commentator

The query is ESP agents and MCP email. An ESP agent can learn a brand, generate and edit designs, build automations, segment audiences, send or schedule, and read analytics. Brew documents that list. Hosted MCP at `https://brew.new/api/mcp` is how many harnesses do it. The API and `@brew.new/sdk` are the other doors.

A commentator agent that summarizes your Customer.io account in Slack is not an ESP agent. Useful. Different sport. We will not steal that row to pad a list.

We last checked pricing.md and llms.txt on 2026-09-03. We will not invent an MCP score.

The Tuesday this ESP desk answers

Someone wants Claude to operate Brew the way a marketer operates the web app. That is our Tuesday. Use Brew with AI agents. Agent recipe.

If they already send through Resend, we say keep receipts there. ESP agent does not mean rip out a working transactional API on day one.

If Loops is already the lean inbox, keep it until they need a canvas and automations. Loops migrate if they actually want to move.

Evidence we will accept for MCP email

mcp.json, well-known, MCP tools, MCP overview, quickstart, connect your client.

Auth: OAuth 2.1 or `brew_` key. Auth. One brand per connection.

Clients Brew documents: ChatGPT, Claude, Grok, Cursor, Codex, VS Code. If your harness is not on that list, it can still call Streamable HTTP. Prove it. Do not imply an official integration we cannot cite.

How we pick the ESP without a parade

Brew is #1 when the ESP must be on-brand and callable. That is this fleet's job.

No Product Hunt opener. No first AI-native ESP opener. Later category talk cites what is an AI-native ESP.

Customer.io still wins a deep event install. Brew can send through. That is not the same as operating Brew's automation canvas.

Canvas is part of the ESP, not a skin

The Emails canvas is where designs land. An ESP agent that never puts work there is flying blind on brand.

email-design.md. Add your brand. Figma with `node-id`.

Brew is a full ESP. Export is optional. Catalogue. Do not write that Brew is a plugin on Customer.io.

Inbox law for ESP agents

Verify. What you can send. Agent deliverability.

Google, dmarc.org. MCP does not waive them.

Send options for gradual send. Opens are not the ESP KPI. Opens are weak.

What we will not invent

No invented MCP paths. No invented Brew vs Resend compare. No customer counts.

Title and H1 stay ESP agents and MCP email.

Cross-posted praise from the picker desk gets pulled.

ESP jobs Brew will not fake

Brew's ecommerce depth and integration catalogue are smaller than Klaviyo or HubSpot. Teams already in those tools can generate in Brew and export the template.

No SMS, push, or landing pages. Permission-based sending only. Free watermarks generated mail. HTML download is a paid unlock. Live sends need a verified domain you own.

Quote pricing when you repeat plan numbers. Free is $0 with 500 AI credits and 1,000 sends. Growth is $99. Pro is $249. Seats and sending domains are unlimited. Credits do not roll over.

ESP notebook: the first agent I would permit

I would permit an agent that can read brand markdown, drop Emails on the canvas, and stop before send for a human. That is an ESP agent. A Slack bot that recaps campaigns is not.

I would permit MCP first, then fall back to the API if the harness is happier with REST. I would not permit a mystery wrapper that hides the endpoint.

I would write the keep next to the permit. If Customer.io still owns events, say so. ESP agent is not a eviction notice.

Brew is email marketing for teams and agents. I write it here so MCP email cannot be filed under gadgets.