MCP server

marginal Official

sh.marginal/mcp

Checked 26 Oct 2026, 08:29 UTC · It answered and asked for a sign-in

Email A/B tests for AI agents: subject lines, managed sends, open/click tracking, and results.

Needs an API keyVerified publisher: marginal.sh

https://marginal.sh/mcp

At a glance

Type: MCP server
Publisher: marginal.sh (verified by the MCP Registry)
Status: Needs an API key
Sets up in: Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok
Last checked: 26 Oct 2026, 08:29 UTC

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http marginal https://marginal.sh/mcp

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.marginal]
url = "https://marginal.sh/mcp"

Gemini CLI

{"mcpServers":{"marginal":{"httpUrl":"https://marginal.sh/mcp"}}}

Cursor

{"mcpServers":{"marginal":{"url":"https://marginal.sh/mcp"}}}

VS Code

{"servers":{"marginal":{"type":"http","url":"https://marginal.sh/mcp"}}}

Antigravity

agy mcp add marginal https://marginal.sh/mcp

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"marginal","server_url":"https://marginal.sh/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"marginal","server_url":"https://marginal.sh/mcp"}

Needs an API key or token from its maker, usually added as a header in the setup.

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