How to Connect Grok to Cold Email

Short answer: Grok has three ways to reach outside tools. Grok Build, xAI's command-line agent (beta since May 2026), runs local MCP servers and shell commands, so it works with the Outreach2day REST API today. grok.com connectors accept a custom MCP server URL, and the xAI API has accepted remote MCP servers as tools since November 2025; both need a server on the public internet. Outreach2day's hosted MCP server is in early access, so for grok.com and the xAI API there is no URL to paste yet.

Checked September 2026 against xAI's Connectors, Grok Build MCP servers, Remote MCP tools and release notes.

Connection Methods

Connectors are available to all Grok users, per xAI. On Grok Business and Enterprise a team admin provisions a connector first in the xAI console. A custom connector must be reachable over the public internet (xAI suggests a tunnel for a server on your own machine), which is why the local server below works in Grok Build but not on grok.com.

What Grok Can Do With Your Cold Email Setup

Through the local server from our cold email MCP server guide, Grok Build gets six read-only tools, named outreach2day__<tool> in Grok:

• Workspaces and domains: which workspaces the key sees, which domains each has and how many mailboxes sit on each.

• Domain checks: whether up to 50 names are free, taken or not allowed. Nothing is bought.

• Mailboxes and warm-up: each mailbox's status and warmupState (not_started, warming, paused, error, disabled), and when warm-up started.

• Replies: the latest reply threads with their intent label, for a quick daily read.

Grok is also useful before any of that: researching a market, finding angles for an offer, writing first drafts. Keep those drafts inside our sending rules: at most 25 cold emails per mailbox a day, 5 mailboxes per domain, 14 days of warm-up, no links, follow-ups after 2, 3, 5 and 5 days.

Connect Grok Build to Outreach2day, step by step

1. Install Grok Build. Follow xAI's install command in the Grok Build docs. It is in beta.

2. Create an API key. In the Outreach2day app, open the API keys page and create a key only for Grok (ot2d_...). Export it: export O2D_KEY=ot2d_... and export O2D_WORKSPACE_ID=123.

3. Save the server. Copy o2d_mcp.py from the cold email MCP server guide and install mcp and requests in a virtual environment.

4. Declare it in ~/.grok/config.toml. Grok expands ${VAR} in env at load time, so the key stays in your environment (block below). grok mcp add outreach2day -- <command> writes a similar entry from the command line.

5. Check and test. Run grok mcp doctor outreach2day, then ask Grok "which of my mailboxes are still warming?" and compare with the app.

[mcp_servers.outreach2day]
command = "/path/to/.venv/bin/python"
args = ["/path/to/o2d_mcp.py"]
env = { O2D_API_KEY = "${O2D_KEY}", O2D_WORKSPACE_ID = "${O2D_WORKSPACE_ID}" }

Grok Build also reads MCP entries from ~/.claude.json, .cursor/mcp.json and project .mcp.json files, so a server you already set up for Claude Code or Cursor shows up without a second config.

grok.com and the xAI API (Early Access)

Both need a hosted MCP server. On grok.com you would add it under Connectors, New Connector, Custom; in the xAI Responses API you would pass it as a tool with server_url and an authorization token. Outreach2day's hosted server is in early access and has no public URL yet, so this page shows none. Get early access on the home page. Until then, xAI API developers can call the REST API with ordinary function calling in their own code.

Prompts to Try in Grok

• "Which mailboxes have warmed for at least 14 days? Group them by domain and count them."

• "Check these 15 domain ideas and list only the free ones. Do not buy."

• "Summarise yesterday's replies by intent. Quote the one sentence that decided each label."

• "Find three recent public news items about Acme Corp I could open a cold email with. Give each with its source."

Fifteen more are in Grok prompts for cold email.

Limits and Safety

• Rate limits: the Outreach2day API allows 10 requests a second and 1,000 an hour per user and per workspace.

• Tool approvals. Review what Grok Build is about to run. Buying domains through the API is paid right away — give an agent a billing-scoped key only if you want it to buy.

• Reply text is untrusted. Replies are written by outsiders; Grok should read them as data, never as instructions.

• Public servers only on grok.com. Do not expose a local server with your key through a tunnel just to reach grok.com. Wait for the hosted server.

FAQ

Can I connect Grok on grok.com to Outreach2day today?

Not directly. grok.com needs a public MCP server, and Outreach2day's is in early access. Grok Build on your computer works today.

When did Grok get MCP support?

The xAI API added remote MCP tools in November 2025. Grok Build, with local and remote MCP servers, entered beta in May 2026. xAI's connectors page does not give a launch date for custom connectors on grok.com.

Does Grok Build work with the server I set up for Claude Code?

Yes. Grok Build loads MCP entries from ~/.claude.json, .cursor/mcp.json and .mcp.json, below its own config.toml.

Can Grok send my cold emails?

Not with the read-only tools here. Campaigns run in Outreach2day where enabled for your workspace, or in Instantly or Smartlead after export.

Is the API included in my plan?

Yes. API access is part of every plan; see pricing.

Related

• Outreach2day MCP for Grok: what the hosted MCP server covers (early access)

• Other assistants: Claude, Claude Code, ChatGPT, Gemini, Cursor, GitHub Copilot, Windsurf, Copilot Studio, Le Chat, n8n

• AI assistants for cold email: every assistant and how it connects

• How to connect Claude Code to cold email

• Cold email API

Create an account, add mailboxes, then create a key for Grok.

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