For ChatGPT, Claude, Cursor and other AI assistants

ReplyDak MCP server

Run your cold email infrastructure from the AI assistant you already use. Ask it to find sending domains, price and order mailboxes, follow setup, check deliverability or read replies. It works through the Model Context Protocol (MCP), the open standard for connecting assistants to tools.

1. Get an API key

Sign in, open Clients & API in your dashboard and create a key (it starts with rdk_ and is shown once). One key works for the REST API and MCP. Revoke it there any time.

Two ways to send the key. Clients that support custom headers (Claude, Claude Code, Cursor) use https://app.replydak.com/api/mcp with an Authorization: Bearer rdk_… header. Clients that only take a URL (such as ChatGPT connectors) use the private URL https://app.replydak.com/api/mcp/k/rdk_your_key. That URL contains your key: keep it secret like a password, don't share it in screenshots or chats, and revoke the key if it leaks. Sign-in with OAuth, so no key is needed, is coming soon.

2. Connect your assistant

Claude (claude.ai and the desktop app)

Open Settings → Connectors → Add → Add custom connector. Name it ReplyDak, enter the URL below and click Continue anyway when it says it couldn't check sign-in. Choose No sign-in, then under Request headers add Authorization with the value Bearer rdk_your_key, and click Add. This keeps the key out of the URL.

https://app.replydak.com/api/mcp

ChatGPT

Turn on Settings → Apps & Connectors → Advanced settings → Developer mode, then Create a connector. Paste your private URL as the MCP server URL and choose No authentication (the key is in the URL). Pick the connector from the + menu in a chat.

https://app.replydak.com/api/mcp/k/rdk_your_key

Claude Code

Run this once in a terminal. The key travels in a header, not the URL.

claude mcp add --transport http replydak https://app.replydak.com/api/mcp --header "Authorization: Bearer rdk_your_key"

Cursor, VS Code and other MCP clients

Add a remote (Streamable HTTP) server. In Cursor that is ~/.cursor/mcp.json:

{
  "mcpServers": {
    "replydak": {
      "url": "https://app.replydak.com/api/mcp",
      "headers": { "Authorization": "Bearer rdk_your_key" }
    }
  }
}

3. Ask

“Set up 30 cold email inboxes for acme.com, sending as Ana Lopez and Sam Reed.”
“What would 100 mailboxes cost per month in EUR?”
“Check the deliverability of getacme.com and tell me what to fix.”
“Show me this week's interested replies.”
“Is this cold email likely to land in spam? Subject: Quick question…”
“Create a client called Northwind and list its domains' health.”

What your assistant can and can't do

It never pays. Ordering creates an unpaid order and returns the amount and a payment link; you open it, sign in and pay yourself. Setup (domains, SPF, DKIM, DMARC, mailboxes, warmup) starts automatically once it's paid.

It never sees passwords. Mailbox credentials are not available over MCP; download them from your dashboard to load into your sequencer.

Every call is limited to your own workspace, at up to 120 tool calls a minute.

Tools

get_pricing

Quote ReplyDak's price for a number of cold-email mailboxes (Google Workspace or Microsoft 365) and new sending domains. Prices are per mailbox per month with a plan minimum; domains are billed yearly. Use this before create_order to tell the user what it will cost. If new_domains is left out, it assumes one new domain per 3 mailboxes (the safe ratio for cold email).

suggest_domains

Suggest lookalike sending domains for a company's main domain (e.g. acme.com → getacme.com, acmehq.com) and check live which ones are available to buy. Cold email should be sent from such domains, never from the main domain. Returns up to 10 available domains with their first-year price.

check_deliverability

Check any domain's email deliverability setup from public DNS: MX, SPF, DKIM, DMARC and blocklists (Spamhaus, SURBL, URIBL, SpamCop, Barracuda). Returns a score out of 100 and advice per check. Works for domains not on ReplyDak too.

check_email

Review a cold email draft before sending: spam words, length, links, personalisation, call to action and opt-out. Returns a score, a grade (Good / Needs work / Risky) and findings to fix.

list_clients

List the agency's clients with their domain and mailbox counts, average health, monthly cost and private white-label status page link.

create_client

Create a client (one of an agency's end customers). Pass its id as client_id to create_order to put new domains and mailboxes under it.

create_order

Create an UNPAID order for sending domains and mailboxes. Nothing is charged: the result has the amount due and a payUrl that the user must open in a browser and pay themselves; ReplyDak then buys the domains, sets up DNS (SPF, DKIM, DMARC), creates the mailboxes and starts warmup automatically. Always confirm the domains, mailbox count, sender names and price (get_pricing) with the user first. Use suggest_domains to find available domains. Keep 2-3 mailboxes per domain.

get_order

Get an order's payment status and setup progress per domain (buy domain, DNS, verification, mailboxes, DKIM, warmup).

list_domains

List the workspace's sending domains with status, mailbox count and the latest daily health check (score out of 100 plus MX/SPF/DKIM/DMARC/blocklist results).

list_mailboxes

List mailboxes with status, warmup day and today's safe daily sending limit. Never includes passwords: for credentials the user downloads the export from the ReplyDak dashboard.

list_inbox_replies

Latest replies (up to 20) received by the workspace's mailboxes, newest first, each labelled interested / question / referral / not_interested / ooo / unsubscribe / bounce / other. Filter by label to find warm leads.

Technical details

Remote MCP over Streamable HTTP (stateless, JSON responses), protocol versions 2025-11-25, 2025-06-18, 2025-03-26 and 2024-11-05. POST JSON-RPC 2.0 to the endpoint; GET returns 405 because there is no event stream. A missing or revoked key returns 401.

Questions or a tool you need? Write to support@replydak.com.