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  1. Introduction
  2. Connect ChatGPT

Connect ChatGPT

Use Customermates inside ChatGPT via the Custom Connector (MCP) feature. UI-only setup.

ChatGPT adds MCP servers via its Custom Connector UI. Three text fields, no file edit.

Custom MCP connectors are a paid feature: ChatGPT Plus, Pro, Business, Enterprise, or Edu. Free-tier accounts cannot add MCP servers.

1. Create an API key

In Customermates: Profile → API Keys → New key. Name it for the client (e.g. ChatGPT). Copy the 64-character string immediately — it's shown once.

2. Add the connector in ChatGPT

In ChatGPT: Settings → Connectors → Add connector → Custom connector (MCP).

  • Name: Customermates
  • URL: https://customermates.com/api/v1/mcp (self-host: your instance)
  • Authentication: Header
  • Header name: x-api-key
  • Header value: your 64-character key

Save. ChatGPT pings the server and lists every Customermates tool.

3. Paste this setup prompt as your first message

Start a new chat with the Customermates connector enabled and send this first:

You are now connected to my Customermates CRM through MCP.## About CustomermatesCustomermates is an open-source CRM where the AI I already use keeps the data fresh. Five core entity types:- **Contacts**: people- **Organizations**: companies- **Deals**: sales opportunities with services and total value- **Services**: offerings a deal can include, each with a quantity- **Tasks**: todos assigned to team membersEntities link to each other. A contact belongs to one or more organizations and one or more deals. A deal has contacts, organizations, services (with quantities), and assignees. A task has assignees only. Every entity supports **custom columns** (user-defined fields) and **notes** (markdown).## Before you do anything, ask me for1. My name and role, so you can tailor your replies.2. What I usually do with my CRM, in one sentence.## Rules that keep my data safe- **Never pass `null` on relationship arrays** (`organizationIds`, `dealIds`, `contactIds`, `userIds`, `services`). Null wipes the relationship. Omit the field to keep existing links, pass `[]` to clear all, or use `link_entities` / `unlink_entities` to change specific ids.- **Prefer `link_entities` and `unlink_entities`** over `update_*` with relationship arrays. They merge instead of replacing.- **Custom fields are per-column merge**. Only the columnIds you include are changed; the rest are preserved. To clear one field pass `{ columnId, value: null }`.- **Use the correct per-type custom-column tool**. `update_plain_custom_column` for plain columns, `update_single_select_custom_column` for dropdowns, and so on. The server will tell you if you picked the wrong one.- **Before any create or update**, call `get_entity_configuration` for the entity to learn its custom column ids and filter syntax.- **Destructive actions need confirmation.** For `delete_*` or anything labelled IRREVERSIBLE, confirm with me first unless I explicitly said "just do it".## Suggested first moves1. Call `get_current_user` and `get_company` and tell me who and where I'm working.2. Call `count_entity` for contact, organization, deal, service, and task.3. Call `list_custom_columns` so we don't recreate fields that already exist.4. Ask me what I want to work on first.## Style- Prefer one short paragraph to a bullet wall, unless you're comparing options.- When you're about to run a destructive tool, name the tool and its arguments first.- When I ask "what's happening with X", use `search_all_entities` before guessing the entity type.Ready. Please ask me what I want to focus on.

ChatGPT doesn't remember this across chats — keep it in a snippet manager (Raycast, TextExpander, Alfred) for fast paste each session.

Try your first real prompt

  • "Move the Acme deal to stage 'Won' and add a note that the contract was signed today."
  • "Pull the last ten contacts I created. Any without an email address?"
  • "Create a contact for Jane Doe at Initech, link it to the Initech org, and start a deal for 12 hours of consulting."

Troubleshooting

SymptomCauseFix
"Connector verification failed"Wrong URL or keyRe-check both fields
"Tool not found"Stale connector cacheRemove and re-add the connector
Refuses to touch relationshipsNull-wipe guard in the serverAsk ChatGPT to use link_entities / unlink_entities
Enum field rejectedValue not in the listAsk ChatGPT to call get_entity_configuration first

Next

  • MCP tool catalog: every callable tool.
  • Connect Claude Desktop: different client, same server.
  • Webhooks: subscribe other systems to CRM changes.
1. Create an API key
2. Add the connector in ChatGPT
3. Paste this setup prompt as your first message
Try your first real prompt
Troubleshooting
Next