A Custom GPT is a snapshot of your brand guide, and it forgets by message thirty. The connector is a phone line: every prompt starts from your real voice, offer, calendar, and live automations, and every draft lands in Marqeable for approval.
Available on Plus, Pro, Business, and Enterprise. Business and Enterprise admins may need to allowlist the server first.
Steps verified against OpenAI's Developer mode guide on 1 September 2026. Vendors rename menus often; if a step looks different, the server URL is the part that does not change.
Open Settings, then Security and login, then Developer mode. Turn it on.
Open Plugins, then Create. Name it Marqeable, paste the MCP server URL, and set Authentication to OAuth.
https://app.marqeable.com/mcpClick Create, then sign in with your Marqeable account when the browser opens.
In a chat, add Marqeable from the tools menu and run the first prompt below. ChatGPT may ask you to confirm each write tool once per conversation.
Before the July 2026 rename the path was Settings, then Connectors, then Advanced, then Developer mode. The server URL is the same either way.
Start with a read so you can see the assistant using your real business context. Then ask for one draft and open Marqeable to find it waiting for approval.
whoamiget_business_contextget_content_calendarsearch_contentcreate_content_draftEvery write is a draft. No send, launch, or delete tools.
A shareable persona for a contractor still works. For anything that needs the calendar, the campaign list, or a draft that actually lands somewhere, use the connector.
HubSpot answers who and can drop a marketing-email draft. It cannot tell ChatGPT what your brand sounds like or what nurture a lead is already getting. Run both in one chat.
ChatGPT may ask before each write. That is a courtesy, not the gate. The gate is that Marqeable exposes no send, launch, or delete tool at all.
Judge any connector by its tool list. This is ours, in full. There is no send, launch, or delete tool, so a bad prompt, a scheduled run, or a poisoned web page can never reach your list. The gate is structural, not a permission click.
get_business_contextBrand, voice, offer, audience, what you sell and to whom.get_content_calendarWhat is scheduled, so a draft never collides with a send.list_campaignsEvery campaign and its status.get_campaignOne campaign, all its pieces.search_contentFind last quarter's launch email before rewriting it.get_contentOne piece, full copy and brief.get_automation_overviewWhich automations are live and who is inside them.get_automation_planThe steps, timing, and triggers of one automation.search_image_libraryImages you already own, so nothing is regenerated by accident.whoamiWhich user and account the assistant is acting as.create_campaign_draftA campaign with its pieces, saved as a draft.create_content_draftOne email, post, or page. Copy first, no image spend.create_automation_draftA follow-up sequence, assembled but not launched.update_automation_draftChange a step or the timing on a draft.update_content_briefAdjust the brief before the copy is written.add_content_suggestionLeave a note on a draft for whoever reviews it.request_content_changesSend a draft back with what to fix.approve_content_buildSay yes to the images for a draft you have already read.Sign-in is OAuth 2.1 per user, so no API key is ever pasted into a chat. Multi-account users also get list_accounts and switch_account.
A Custom GPT is a snapshot of your brand guide. An MCP connector is a live line into your campaigns, calendar and automations. What each can do, and when a Custom GPT still wins.
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