MCP server for ChatGPT
Cold email MCP server for ChatGPT and the OpenAI API
Give ChatGPT or your OpenAI agent the tools to run cold email: domains, mailboxes, warmup, campaigns and replies. In ChatGPT the assistant checks domains, mailboxes, warmup and campaigns and reports back until the campaign is live; orders go through the Outreach2day web app.
https://public.outreach2day.com/mcp
Copies the server URL and opens Plugins. Enable Developer mode, then create an app.
Setup guide
- In Settings → Security and login, turn on Developer mode
- Create an app named Outreach2day and paste the server URL under Connection
- Add the app to a chat and sign in with your Outreach2day account
- Orders paid through Stripe after you approve them
- $2.50 per mailbox a month
We ordered 20 mailboxes for the new outbound team. Which ones are ready to send?
called outreach2day tools
20 mailboxes on 5 domains: northwindhq.com, getnorthwind.com, trynorthwind.info, northwind-mail.com, meetnorthwind.info.
16 are ready. The 4 on meetnorthwind.info are on day 11 of warmup and ready on Oct 2.
The Q4 campaign can start with the 16 ready mailboxes. Attach them?
- teams have used Outreach2day
- 3,600+
- emails sent a day
- 40M+
Among them
Can ChatGPT run cold email through MCP?
Yes. The ChatGPT app (developer mode, paid plans) and Codex CLI add the server by URL and sign in to Outreach2day with OAuth. In ChatGPT the assistant checks domains, mailboxes, warmup and campaigns and reads replies; orders go through the Outreach2day web app. The OpenAI Responses API takes the server with an API key, per OpenAI's docs; we have not tested that path yet.
Cold email in ChatGPT, step by step
- 1
Connect once
Add the server as an app in ChatGPT and sign in, or pass it to a Responses API call with your key. The model picks the Outreach2day tools it needs
- 2
Order in the web app
Buy domains and mailboxes in the Outreach2day app. ChatGPT can read the order and follow setup after you pay
- 3
Follow the order
The model polls the order until domains, DNS and mailboxes are done, then starts warmup
- 4
Run the campaign
After 14 days of warmup it builds the sequence, launches it and pulls replies and per-mailbox stats into your workflow
Outreach2day in ChatGPT: where to connect
- OAuth sign-in
ChatGPT (developer mode)
A developer-mode app at chatgpt.com/plugins; signs in with OAuth
OpenAI docs: ChatGPT developer mode - API key in a header
OpenAI Responses API
An mcp tool in the request, with the key in authorization; per OpenAI's docs, untested by us so far
OpenAI docs: MCP and connectors
Setup details
ChatGPT: files, sign-in and limits
What ChatGPT's own documentation says about connecting a remote MCP server.
- Turn on developer mode
- Settings, Security and login, Developer mode. Available on Pro, Plus, Business, Enterprise and Education accounts, on the web. OpenAI docs: ChatGPT developer mode
- Create the app
- Go to chatgpt.com/plugins, click +, and create a developer-mode app with the server URL. It appears under Drafts; in a chat, pick Developer mode from the + menu. OpenAI docs: ChatGPT developer mode
- Sign-in
- ChatGPT connects remote servers with OAuth or with no authentication. It cannot send a custom API key, so you sign in with your Outreach2day account. OpenAI Apps SDK: authentication
- Confirmations
- Tools without a readOnlyHint are treated as write actions and ChatGPT asks before each call. You can remember the approval for one conversation; a new conversation asks again. OpenAI docs: ChatGPT developer mode
- Transport
- SSE and streaming HTTP. OpenAI docs: ChatGPT developer mode
- OpenAI Responses API
- An mcp tool with server_url and authorization. The value is not stored, so it goes with every request; require_approval defaults to always and allowed_tools limits the list. OpenAI docs: MCP and connectorsOpenAI Responses API
curl https://api.openai.com/v1/responses \ -H "Authorization: Bearer $OPENAI_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-5", "input": "Which of my mailboxes are ready to send?", "tools": [{ "type": "mcp", "server_label": "outreach2day", "server_url": "https://public.outreach2day.com/mcp", "authorization": "'"$OUTREACH2DAY_API_KEY"'", "require_approval": "always" }] }'
Works with Outreach2day
- ChatGPT on the web with developer mode and OAuth sign-in
- The Responses API with an authorization value (per OpenAI's docs; not tested by us yet)
- Codex CLI, the IDE extension and the ChatGPT desktop app through config.toml (see the Codex page)
Does not work
- Pasting an API key into ChatGPT: the app signs in with OAuth only
- Developer mode in the mobile apps: OpenAI documents it for the web
- The client-credentials OAuth grant
In ChatGPT the assistant gets the tools for domains, mailboxes, warmup, campaigns and replies, and orders go through the Outreach2day web app. Every other client gets the same tools plus orders: tool list, what the agent can and cannot do.
Prompts
Things to ask ChatGPT
Plain language is enough. The agent picks the tools and asks before anything costs money.
- List our purchased domains and show which ones still need DNS setup.
- List every mailbox with its warmup inbox rate, lowest first.
- Import contacts.csv into the Q4 campaign and run the preflight check.
- Summarize this week's replies by campaign: interested, not now, unsubscribe.
- Export the 12 warm mailboxes on northwindhq.com to our Instantly workspace.
What ChatGPT can do with the server, job by job
Each page lists the tools for the job, an example session, prompts per assistant and the limits.
- Outbound end to endDomains, mailboxes, warmup, campaign and replies from one assistant
- Domains and mailboxesCheck names, quote, pay on Stripe and track setup; or connect your own domains
- WarmupStart warmup and get inbox rate, spam rate and ready date per mailbox
- CampaignsDraft the sequence, import contacts, launch, read stats and replies
Setup
Connect ChatGPT
Add https://public.outreach2day.com/mcp to ChatGPT and sign in with your Outreach2day account when it asks. Then ask: "Check my Outreach2day account status". An API key is only for CI and headless setups.
Setup steps
ChatGPT (developer mode)
- Settings, Security and login: turn on Developer mode
- Go to chatgpt.com/plugins, click +, name the app Outreach2day, enter the server URL under Connection and create it
- In a new chat, add Outreach2day from the tools menu. ChatGPT opens the Outreach2day sign-in page on the first tool call; sign in and allow access
OpenAI Responses API
- Create an API key in the Outreach2day app (API keys, New key) and export it as OUTREACH2DAY_API_KEY
- Add Outreach2day as an mcp tool in the request; the key goes in authorization and is sent with every call
curl https://api.openai.com/v1/responses \ -H "Authorization: Bearer $OPENAI_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-5", "input": "Which of my mailboxes are ready to send?", "tools": [{ "type": "mcp", "server_label": "outreach2day", "server_url": "https://public.outreach2day.com/mcp", "authorization": "'"$OUTREACH2DAY_API_KEY"'", "require_approval": "always" }] }'Book a call
Book a 30-minute call
Talk to the team that runs the MCP server. We check your setup for ChatGPT and your first order.
- Free 30-minute call
- Size domains and mailboxes for your volume
- Walk through a quote and the Stripe checkout
- Check your ChatGPT setup
See open times in your time zone and book on this page.
Or open the booking pageLoading available times…
Open the booking page insteadCustomers
Teams that send with Outreach2day
“That was the best infrastructure and value for money I saw.”
“…deliverability with your inboxes is better than our outlook/google inboxes…”
“We really would like to thank you for that report. We don’t know what we are doing with email and it is very reassuring to us to know we have a partner on top of the ball.”
Questions
Or talk to the teamCan I add the Outreach2day MCP server to the ChatGPT app?
Yes, on Pro, Plus, Business, Enterprise and Education accounts on the web. Turn on developer mode, create an app at chatgpt.com/plugins with the server URL and sign in with your Outreach2day account.
Why does ChatGPT ask before every tool call?
ChatGPT treats any tool without a read-only hint as a write action and asks first. Approve once per conversation for tools you trust.
How do I order domains and mailboxes when I work in ChatGPT?
In the Outreach2day web app. ChatGPT then follows the order, starts warmup and runs the campaigns. Claude, Codex, Cursor and VS Code can also quote orders and create a Stripe checkout link when you turn on Prepare orders at sign-in.
Do I need to write code to use it with OpenAI?
Not in ChatGPT. With the Responses API, one tool entry in your request is enough: the model reads the tool list from our server and calls the tools itself.
Other AI clients
The same server and the same tools in every client. Only the setup differs.
Guides for MCP and the API
- Cold Email API for Domains, Warmup and RepliesWhat the Outreach2day cold email API covers: keys, workspaces, domain checks and purchase, mailbox lists, warmup, replies and export to Instantly or Smartlead.
- MCP for Cold Email Infrastructure: Domains and MailboxesGive an AI agent your cold email infrastructure through MCP: check domains, connect your own, list mailboxes. Which actions to allow, which to keep manual.
- Email Warmup API: Start, Pause and MonitorHow to run mailbox warmup through the Outreach2day email warmup API: enable, pause and disable operations, idempotency keys, polling and warmup states.
Run cold email from ChatGPT
Domains, mailboxes, warmup, campaigns and replies from ChatGPT. You approve every order.