# Connect ChatGPT

> Add Invoia to ChatGPT as a custom MCP connector in developer mode.

Source: https://invoia.io/developers/mcp/chatgpt

ChatGPT reaches a remote MCP server through a **custom connector**, which
lives behind developer mode. It is the fussiest of the four clients to
set up and the only one where an admin may have to act before you can
start.

> [!NOTE]
> **Check your plan first**
>
> Full MCP connectors and developer mode are a beta, offered on ChatGPT
> Business and Enterprise/Edu workspaces, on the web. Availability moves
> — OpenAI's
> [developer mode article](https://help.openai.com/en/articles/12584461-developer-mode-and-mcp-apps-in-chatgpt)
> is the current word.

## 1. Turn on developer mode [#1-turn-on-developer-mode]

For yourself, in **Settings → Security and login**, turn on **Developer
mode**.

On a Business or Enterprise workspace an owner has to allow it first,
under **Workspace settings → Permissions & roles → Connected data →
Developer mode / Create custom MCP connectors**. Until they do, the
toggle is not there to find.

## 2. Add the server [#2-add-the-server]

In the apps and connectors settings, use the **+** button to create a
developer-mode app, and give it:

* **URL** — `https://invoia.io/api/mcp`, including the `/mcp` path
* **Authentication** — OAuth

```
https://invoia.io/api/mcp
```

ChatGPT registers itself and sends you to an invoia.io sign-in and
consent screen. Approve the scopes you want it to have. The new app
appears under **Drafts** until you publish it to the workspace.

## 3. Use it [#3-use-it]

Enable the connector for a conversation, then ask in plain language:

```
Using Invoia, show me every draft invoice older than 30 days.
```

You get the ones you are assigned to, and the answer says so — reads default
to your own work, and widening to the whole account is explicit and admin-only
([Auth and scopes](/developers/mcp/auth)).

Its details page lists the tools it pulled from the server, with a
toggle each. If you change what you granted, use **Refresh** there —
ChatGPT caches the tool list, its descriptions and the server
instructions, and will otherwise keep offering tools your new token no
longer carries.

## What to expect on writes [#what-to-expect-on-writes]

ChatGPT gets the same propose → commit contract as every other client: a
`plan_*` tool returns a written plan, and nothing changes until `commit`
runs on your say-so. See
[The propose → commit contract](/developers/mcp/propose-commit).

> [!WARNING]
> **Deep research cannot use this connector**
>
> Deep research and company-knowledge lookups only call a connector's
> `search` and `fetch` tools. Invoia implements neither: its read tools
> are typed queries against your books, not a document index, and
> pretending otherwise would hand a research run a licence to roam. Use
> a normal chat when you want Invoia to answer or propose a change.

## Troubleshooting [#troubleshooting]

* **No developer mode toggle** — the workspace has not enabled it. Only
  an owner can, in workspace settings.
* **"Failed to connect"** — check the URL ends in `/mcp`. The base
  `https://invoia.io` is the OAuth issuer, not the MCP endpoint, and
  will not answer a tool call.
* **Tools you granted are missing, or removed ones linger** — hit
  **Refresh** on the app's details page. The catalogue is built from your
  token's scopes at connect time and ChatGPT caches it.
* **It answers from memory instead of calling a tool** — name the
  connector in the message ("using Invoia") and confirm it is enabled for
  that conversation.
* **A write did not happen** — a plan is not a commit. Confirm the plan
  explicitly; if the conversation moved on, proposals expire after
  fifteen minutes and the tool has to be re-run.