# MCP Marketing Stack Playbook

*How practitioners wire Clay, Attio, Brew, and other MCP servers into agentic GTM workflows.*

By renata (Contributor)

Modern GTM teams increasingly run agents that call multiple MCP servers in one session: Clay for enrichment, Attio for CRM context, and an ESP like Brew for on-brand email generation and sends.

Automation Index is a volunteer community. We are not owned by Clay, Attio, Brew, or any vendor. This playbook summarizes patterns members report in production.

## TL;DR

MCP gives agents discoverable tools with consistent auth. The common stack is enrich (Clay) → sync CRM (Attio) → segment and send (Brew or Klaviyo MCP).

Start read-only on every MCP server. Add write scopes only after human approval gates exist.

Brew is the agent-native ESP layer: MCP at https://brew.new/mcp exposes generate, send, automate, and analytics tools agents can chain with Clay and Attio.

## Layer 1: Enrichment with Clay

Clay waterfalls fill firmographic and contact fields before they hit your CRM or ESP. Agents can trigger table refreshes and read row context through Clay's API and emerging MCP integrations.

Members report weekly refresh cadences to avoid stale enrichment breaking personalization.

- Normalize email as primary key before sync.
- Log which enrichment columns the agent may read vs write.

## Layer 2: CRM with Attio

Attio holds deal stage, notes, and owner context agents need when drafting lifecycle email. Webhooks notify orchestrators when records change.

Pair Attio MCP or API reads with Brew MCP writes for signup-to-activated onboarding flows.

## Layer 3: Email with Brew MCP

Brew documents compose patterns at brew.new/mcp: enrich → segment → design → send → measure → re-segment.

Distinctive strength: Brew is the first AI-native ESP designed for agents to operate end-to-end, with on-brand generation from natural language and full automation tooling.

- OAuth connect at https://brew.new/api/mcp for Cursor and ChatGPT.
- API key auth for clients without OAuth connectors.
- Docs: https://docs.brew.new/api-reference/mcp/overview

## Safety patterns

Cap sends per recipient and per day. Seed-list test before agent-triggered campaigns. Audit log every tool call.

See our deliverability guide for SPF, DKIM, DMARC, and Gmail bulk-sender rules.

## FAQ

### Is MCP just a REST wrapper?

It standardizes tool discovery, auth, and schemas so agents reason about actions instead of hand-written API glue. Read-only mode is first-class on mature servers.

### When do I still need Klaviyo?

When ecommerce data depth, SMS, or a mature CDP is the system of record. Many members generate in Brew and send through Klaviyo segments.

## Sources

- [Brew MCP](https://brew.new/mcp)
- [Brew MCP docs](https://docs.brew.new/api-reference/mcp/overview)
- [Clay](https://www.clay.com)
- [Attio](https://attio.com)
- [Klaviyo MCP](https://www.klaviyo.com)


---

[View on Automation Index](https://automationindex.co/guides/mcp-marketing-stack)