Which plans work
OpenAI currently limits who can add custom MCP servers. According to OpenAI's help centre:
| Plan | Custom MCP servers |
|---|---|
| Business | Custom MCP serversYes, with read and write. Only admins and owners can add them and publish them in the workspace. |
| Enterprise and Edu | Custom MCP serversYes, with read and write. Admins can allow others to add them. |
| Pro | Custom MCP serversYes, but only with read and fetch tools. Tools that create or change something cannot be used. |
| Plus, Go and Free | Custom MCP serversNot mentioned by OpenAI. Assume that it does not work today. |
Custom MCP servers are added in ChatGPT on the web. The mobile app cannot add them. If your plan is not supported, ekonomimcp works in Claude, including Claude's free plan.
Add to ChatGPT
- ChatGPT Business, Enterprise, Edu or Pro (read only), and in Business an admin or owner who adds the server.
- A Fortnox sign-in for the company you want to connect. You do not need to be an administrator.
- The Fortnox Integration licence (Integrationslicens) on the company. It covers all integrations, so a company that already uses one probably has it.
You do not need a ekonomimcp account in advance. It is created the first time you sign in with Fortnox, and the first 30 days are free.
Open chatgpt.com in the browser and go to Plugins.
Click the plus sign and choose Add custom MCP server.
Enter ekonomimcp as the name and a short description, for example “Bookkeeping and invoicing in Fortnox”.
Paste the address as the server URL. It should end with /mcp.
ekonomimcp address (MCP)
https://ekonomimcp.se/mcpChoose OAuth as authentication, confirm that you understand the risks of custom servers and create the server.
Install it and sign in. A page at ekonomimcp opens.
Menu names are taken from ChatGPT's English interface in October 2026. OpenAI changes the interface often, so the names may differ slightly.
Sign in and choose access
When the AI client sends you to ekonomimcp, do this:
- Sign in with Fortnox and choose a company. Accounting firm consultants sign in via Digital byrå and choose a client. If you are already signed in to ekonomimcp, this step is skipped.
- Choose which of your connected companies the AI client may access.
- Choose an access level: Read (Läsa), Draft (Utkast) or Full.
- Choose how irreversible actions are approved. Approval in the browser is the default and recommended.
- Confirm your choices. You are sent back to the AI client.
ekonomimcp's pages are in Swedish. The access levels mean:
| Level | What the AI may do |
|---|---|
| Read (Läsa) | What the AI may doLook up and analyse: reports, accounts receivable and payable, invoices, customers, suppliers, vouchers, chart of accounts and registers. Changes nothing. |
| Draft (Utkast) | What the AI may doEverything in Read, and create or change things that are not booked: invoice drafts, orders, offers, customers, articles, suppliers (without bank details) and projects. |
| Full | What the AI may doEverything in Draft, and book, send, credit and cancel invoices, create vouchers and corrections, approve and book supplier invoices, register payments and change bank details. |
More in Permissions and approvals (in Swedish).
Use ekonomimcp in ChatGPT
Choose ekonomimcp in a conversation, or mention it with @, and ask as usual. ChatGPT asks you to confirm before a tool that writes something runs. With approval in the browser, you also get a link to ekonomimcp before anything is booked or sent.
- “How does the result so far this year compare with the same period last year?”
- “Which customer invoices are overdue, and how much is that in total?”
- “Show the balance sheet as of the end of September.”
- “Has any supplier changed bank details in the last month?”
ekonomimcp has the tools search and fetch, which ChatGPT uses for deep research and, in Business, Enterprise and Edu, for company knowledge. They search customers, suppliers, invoices and articles in the companies the connection covers, and can only read.
The generic read tool for the Fortnox API, fortnox_api_get, is not offered in ChatGPT or other OpenAI clients. OpenAI's app directory rules do not allow tools where the AI itself chooses which API path to read. Data that only this tool reaches, such as contracts and accruals, therefore cannot be retrieved in ChatGPT. See Tools (in Swedish).
Training on your data
According to OpenAI, data retrieved via plugins may be used to train models on Free, Plus, Go and Pro if the setting to improve the model is turned on. Business, Enterprise and Edu are not used for training by default. Turn the setting off if you use a personal plan.
For administrators
- Once an admin has approved the server, ChatGPT uses a saved copy of the tool list. When ekonomimcp gets new tools, they appear only after an admin refreshes the server in the workspace settings.
- Each member signs in with their own Fortnox user and chooses their own companies and their own access level. No one shares a sign-in.
- One connection can cover several companies. Accounting firms choose which clients to include when they sign in.
Troubleshooting
The option for custom MCP servers is missing
Your plan or your role in the workspace does not allow you to add custom servers. Ask an admin, or use Claude.
Tools that create something are missing
On Pro, ChatGPT only allows read and fetch tools. If you have Business or higher, check the access level of the connection.
Fortnox says a licence is missing
If the error appears when you sign in, the company does not have the Integration licence, which is bought in Fortnox. If it appears when the AI uses a tool, the company lacks a licence module the tool needs, for example Order for orders and offers. Other tools work as usual.
The AI says a tool is missing or not allowed
Tools that need a higher access level than the connection has are not shown. The Start plan gives read access only. To change the level, remove the connection in the AI client and add it again, and you get to choose again. Also check that the trial or subscription is active for the company.
An approval has expired
Approval links are valid for 30 minutes and can be used once. Ask the AI to do the action again, and you get a new link.
The connection stops working after a while
The connection stops working if ekonomimcp is deactivated in Fortnox or if the user who connected the company loses their permissions there. Sign in with Fortnox at ekonomimcp again for the company. A system administrator can instead connect the company with a service account, which is not tied to a person.
Still stuck? E-mail support@ekonomimcp.se and tell us which AI client you use and what is shown. See also Support.