Ternary MCP for ChatGPT

This guide connects ChatGPT to your Ternary data. It applies to both chatgpt.com and the ChatGPT desktop app (macOS/Windows) — connectors belong to your ChatGPT account, so you set them up once and they work everywhere you're signed in, and the settings screens are the same in both. The mobile apps can use a connector you've already added, but adding one must happen on web or desktop.

ChatGPT supports custom MCP connectors in two distinct modes, and what Ternary can do differs between them:

Mode	Tools available	What that means
Developer mode (regular chats)	All Ternary tools	Full experience: tenant discovery, ad-hoc cost queries, saved reports.
Deep research	`search` and `fetch` only	ChatGPT can find and read your tenants and saved reports, but cannot run ad-hoc cost queries.

This is a ChatGPT platform restriction, not a Ternary one: deep research connectors are limited by OpenAI to the search/fetch contract. For cost analysis, use developer mode.

Requirements

A ChatGPT Plus, Pro, Business, Enterprise, or Edu plan. Custom connectors are not available on the free plan.
A Ternary account (the email you use to sign in to Ternary).
On Business/Enterprise/Edu workspaces, an admin may need to enable custom connectors and developer mode.

Add the connector

In chatgpt.com or the desktop app, open Settings → Connectors (under Apps & Connectors in some layouts).
Under Advanced settings, enable Developer mode if you want the full tool set (recommended).
Click Create (or Add custom connector).
Fill in the form:
- Name: Ternary.
- MCP server URL: your region's server URL:
  - US: https://core-api.ternary.app/mcp
  - EU: https://core-api.eu.ternary.app/mcp
- Authentication: OAuth.
- Check the trust confirmation and click Create.
ChatGPT opens a Ternary sign-in window. Log in with your Ternary credentials and approve the access request.

Use it in a chat

Start a new chat.
Open the + (tools) menu, choose Developer mode, and enable the Ternary connector for the conversation.
Ask a cost question.

Good first prompts:

"Which Ternary tenants can I access?"
"Show my total cloud spend for last month, grouped by service."
"Run a cost query for Q2 grouped by provider."

For deep research: start a Deep research run, add Ternary as a source, and ChatGPT will use search/fetch to pull in your saved reports as reference material.

Troubleshooting

Connector creation fails — verify the exact URL including the /mcp path and the right region, then retry once (a first attempt can time out while the service warms up).
Sign-in fails — your email must belong to an existing Ternary user in that region. US and EU accounts are separate.
"No tenants found" — your Ternary user has no explicit role on any tenant. Ask your Ternary admin to grant you a role.
Only search and fetch appear — you're in deep research mode or developer mode is off. Enable developer mode in connector settings and select it in the chat's tools menu.
ChatGPT asks for confirmation on every tool call — expected in developer mode for connectors it hasn't learned to trust; you can allow per-conversation.