How to Publish an MCP Email Server
If you're searching for how to publish an MCP email server, the fastest path is to skip the infrastructure entirely. marginal is a hosted email MCP server that exposes email marketing tools to AI agents over a single endpoint — no servers to deploy, register, or maintain.
Why "publishing" usually means "connecting"
When people ask how to publish an MCP email server, they often expect to build one from scratch: define tools, host a process, manage auth, and keep it online. That's real work, and email adds extra weight — deliverability, send queues, tracking pixels, and result aggregation.
marginal removes that burden. It's a hosted email MCP server already published at a stable endpoint, so your agent connects to it instead of you operating one. You get a production-ready set of email marketing tools without writing or deploying server code.
- Endpoint: https://marginal.sh/mcp
- Registry identifier: sh.marginal/mcp
- Auth: Bearer API key (marg_live_...)
- No self-hosting — marginal runs the server for you
What the email MCP server exposes
Once connected, an AI agent can run a complete subject line A/B test loop through MCP tools. The server handles managed sends and open/click tracking so the agent only reasons about strategy, not plumbing.
- generate_variants — draft subject line options for a test
- launch_test — start a managed send and subject line A/B test
- get_results — pull open/click and within-test lift metrics
- recommend_next — suggest the next step based on results
Connect your agent in a few minutes
Because the server is already published, setup is a connection task. Add the marginal endpoint and your API key to any MCP-capable client, and the tools appear automatically.
marginal works across common AI development environments, so AI agent email marketing fits into the tooling you already use.
- Supported clients include Cursor, Claude Desktop, Claude Code, OpenAI Codex, Windsurf, Cline, Continue, and Zed
- Authenticate with a Bearer key in the marg_live_ format
- Start free with 100 experiments per month
- Read the full setup steps at https://marginal.sh/docs/
When you'd build your own instead
Publishing your own MCP email server makes sense only if you need custom internal tools or proprietary send logic that a hosted service can't provide. For the common case — running a subject line A/B test and letting an AI agent iterate on results — a hosted email MCP server is faster to ship and easier to keep running.
If your goal is reliable, agent-driven email experiments rather than infrastructure ownership, point your agent at https://marginal.sh/mcp and start testing.
Get started with marginal
marginal is a hosted email marketing MCP server at marginal.sh. Sign up free, create an API key, and connect https://marginal.sh/mcp from Cursor, Codex, or Claude Desktop.
- 100 experiments/month on the free tier
- Four MCP tools: generate_variants, launch_test, get_results, recommend_next
- Listed in the MCP Registry as sh.marginal/mcp