Connect the marginal Email MCP Server to Cursor
Wire up marginal as an email MCP server for Cursor so your agent can generate subject line variants, launch A/B tests, and read results without leaving your editor.
Add marginal to Cursor's MCP config
Cursor reads MCP servers from its settings JSON. Add the marginal endpoint with your Bearer API key, then reload Cursor so the new tools register. Because marginal is hosted, there's nothing to install or run locally — Cursor talks directly to https://marginal.sh/mcp.
- Open Cursor Settings → MCP and add a new server entry.
- Point it at the marginal endpoint and supply your marg_live_ key.
- Reload Cursor to surface the marginal tools to the agent.
- Confirm the connection by asking the agent to list available tools.
Example Cursor MCP configuration
Use the snippet below as your Cursor MCP entry. Replace the placeholder with your live key from the marginal dashboard. This is all the email MCP integration Cursor needs.
What your Cursor agent can do with marginal
Once connected, the marginal tools become available to any AI agent email marketing workflow inside Cursor. The agent can draft variants, run a subject line A/B test, then read which variant won — all driven by natural-language prompts.
- generate_variants — produce candidate subject lines for a campaign.
- launch_test — start a managed send and split traffic across variants.
- get_results — pull open/click tracking and within-test lift metrics.
- recommend_next — get the suggested winning variant to send to the rest of your list.
A typical workflow inside Cursor
Ask Cursor something like: "Generate five subject lines for our onboarding email and launch an A/B test." The agent calls generate_variants, then launch_test, and reports the test ID back to you. Later, prompt it to fetch results and the agent returns open and click rates with lift per variant.
The free tier covers 100 experiments per month, which is plenty for iterating on subject lines while you build. Full tool schemas and prompt examples live in the marginal docs at https://marginal.sh/docs/.
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