Connect ChatGPT to Book a Sponsor: a guide for newsletter publishers

How do you add it in ChatGPT?

1. Open Plugins at chatgpt.com/plugins. You should see a plus button.
2. Select the plus button, then Add custom MCP server. A form should open. Name it Book a Sponsor.
3. Under Connection, enter the URL. Paste https://bookasponsor.com/mcp, with the /mcp path.
4. Set no authentication and accept the warning. This server has no accounts. Select I understand and want to continue.
5. Select Create as a plugin. ChatGPT should list the four tools it found.
6. Install it and start a new chat. Type @ in the prompt box and select it, then ask your question.

What does it return? A real prompt and answer

We sent this through OpenAI's Responses API on 6 November 2026 with the server added as an MCP tool, using gpt-4o-mini. The model listed the four tools, called find_newsletter_sponsors with growthdives.com, and wrote the answer below.

Which brands sponsor newsletters like growthdives.com? Answer in 4 lines at most.

Brands that sponsor newsletters like Growth Dives include:

1. Atlassian
2. Figma
3. Pitch
4. Flourish

These companies have recently advertised in various similar newsletters.

The call itself:

{
  "model": "gpt-4o-mini",
  "input": "Which brands sponsor newsletters like growthdives.com?",
  "tools": [{
    "type": "mcp",
    "server_label": "book_a_sponsor",
    "server_url": "https://bookasponsor.com/mcp",
    "require_approval": "never"
  }]
}

OpenAI's API Playground takes the same address under Tools, Add, MCP Server, if you'd rather test it there.

What can ChatGPT do with it?

What can't ChatGPT do with it?

• It returns brands, never people: no buyer names, email addresses or drafted pitches come through this server.
• It can't send a pitch, sign you up, read your account or see your dash. The results link opens your run on bookasponsor.com.
• A scan lists the 8 closest fits, with the total count. The rest are on the results page.
• A new newsletter's scan can take up to a minute, and the same refusals as the website apply, such as adult content.

Sources

• OpenAI: connect and test your plugin, read 6 November 2026
• OpenAI: MCP connections, read 6 November 2026
• Book a Sponsor MCP server reference, read 6 November 2026