Connecting AI to several companies: check which one it reads first

You keep the books for several companies, and you are about to connect AI to FlowAccount through FlowAccount MCP, the connector that lets an AI read data and create documents in the accounting software. The first question is simple: whose numbers is the AI giving you?

The Project, the bot name and the connector name do not decide the company. The company comes from the company picker when you log in to FlowAccount. FlowAccount's own guide says one connection is tied to one company.

At Productize we tested this on ChatGPT, Claude and Grok Bot on October 25 and 28, 2026, with test companies and FlowAccount users who have access to several companies. A few times the AI read the wrong company, but every time it also told us which company it had actually read, so we caught it in time.

Part 1ChatGPT

Plan: we tested on ChatGPT Pro.

Setup

1. Plugins in the left sidebar → Add button, top right → Add custom MCP server. Paste https://mcp.flowaccount.com/mcp, then log in and pick the first company.
2. Open that connector from the Installed list → Manage → Connected accounts → Connect another account, and pick the next company. The same FlowAccount user is fine. Repeat until you have one account per company.
3. Use Rename account to name each account after its company.
4. When you use it, type @ and click the connector in the list, then put the company name in your question.

What we found

• We asked for company B's outstanding invoices by company name. ChatGPT used company B's account and said it did not use the other account because that one is a different company (2 tries: once with different FlowAccount users, once with the same user).
• We asked "Which company are you connected to right now?" ChatGPT checked both accounts and reported both (1 try).
• When the companies sat in separate connectors, general questions went to the first connector in all 4 chats. Even when we named company B, ChatGPT still opened the first connector, which pointed at company A, and suggested we Disconnect (2 chats).
• Projects really do keep memory apart (1 try each way), but they cannot be tied to a connector. Project instructions forbidding company B's connector locked nothing: when we called it, ChatGPT read company B as usual.

Watch out

• Do not type the full connector name yourself. When we typed @FlowAccount B, the input box turned FlowAccount into the chip for the first connector and left B as plain text.
• If ChatGPT tells you to Disconnect while you already have an account for that company, do not. The existing account would switch to the new company. Only do it when an account points at the wrong company.

Part 2Claude

Claude does not officially support several companies yet. When we added a second connector with the same URL, Claude refused it, so we used a workaround.

Setup

1. On claude.ai: Customize → Connectors → Add → Add custom connector. Paste https://mcp.flowaccount.com/mcp, name it after the company, and pick the company on the login screen.
2. For the second company, add another connector with https://mcp.flowaccount.com/mcp?b=1. The third company uses ?b=2. The suffix only makes the URL unique; you still pick the company at login, as before.
3. If a connection finishes without showing the company picker, press Disconnect and Connect again.
4. When you use it, put the company name in your question.

Plan: we tested on a personal Claude account on the Free plan.

What we found

• The ?b=1 workaround connected and showed the company picker as usual (2 companies, personal account, 1 try). A third connector using ?b=2 also connected and named its company correctly (1 try).
• Without a company name, Claude checks every connector. With a company name, it picks the connector whose name matches (1 try).
• A connector we had named company A was reading a third company, because the Claude account reused a login from an earlier test round and never showed the company picker. When we asked, Claude gave the real company name and warned on its own that it did not match the connector name.
• In a Project whose instructions forbade company B's connector, Claude refused to call it and asked us to confirm first. When we replied "Confirmed, make an exception this time," it called it right away (1 try).

Watch out

• The ?b=1 workaround is not in any guide. It may stop working one day.
• If your Claude account has connected to FlowAccount before, ask which company it reads as soon as the connection finishes.

Part 3Grok Bot

Grok Bot is an AI assistant app for Mac where you can set up several assistants, or bots. It is the easiest of the three for several companies, because one plugin can hold several accounts.

Setup

1. Connect apps icon in the left sidebar → Your plugins → flowaccount. In our app this is a custom plugin using the URL https://mcp.flowaccount.com/mcp. We did not note the steps for adding the plugin the first time.
2. Press Add Another Account, log in and pick a company. Repeat until you have one account per company.
3. Use Rename to name each account after its company. If an account points at the wrong company, press Remove and add it again.
4. When you use it, put the company name in your question.

Plan: we tested on Grok's SuperGrok plan at $30 a month, which we signed up for before xAI changed its plans. If you sign up now, Grok Bot starts at the Premium plan, $30 a month (Grok Bot page, Oct 28, 2026).

What we found

• Without a company name, Grok Bot checks every account and tells you which company each one is (1 try).
• With a company name, it picks the matching account (1 try).
• We asked a bot named Demo about company A, and it read it right away through the account named default. The plugin and its accounts belong to the whole app, not to a bot, and we found no setting to tie an account to a bot.

Watch out

• One bot per client keeps your chats tidy, but client B's bot can still open client A's account.

Part 4Which setup fits your work

From safest to weakest: a separate AI account per company (our analysis, not tested). Next, one AI account with one connection per company, plus a company check before work. Weakest is separating only by Project or bot, because it does not restrict access to the data.

To choose, look at who owns the data and how much damage a mix-up would do.

• Owners with several companies: use ChatGPT or Claude with one connection per company. The data is all yours, but picking the wrong company still means cleanup, such as a document issued in the wrong company's name.
• Accounting firms serving many clients*: same approach as above.
• Owners with several branches, or franchisors who look at every store: Grok Bot suits this, because every bot sees every account. It does not suit several franchisees sharing one setup, because they would see each other's accounts. We have not tested FlowAccount branches, because we had no test company with branches. Compare the numbers with the reports in the FlowAccount web app before you rely on them.

* The difference is that the data belongs to your clients. If mixing is never acceptable, use a separate AI account per client, at the cost of a seat per client and no single screen that shows every company.

Part 5Check before every piece of work

1. Pick that company's connector or account yourself (in ChatGPT, type @ and click it in the list), and put the company name in your question.
2. Ask "Which company are you connected to right now?" and compare the answer with the connector or account name.
3. If they do not match, stop. Do not let the AI create documents. Disconnect only the wrong one, then reconnect and pick the right company.

On a busy day you may forget to ask, so we wrote a standing Project instruction called company-guard that has the AI do step 2 for you. Use it with one Claude or ChatGPT Project per company.

1. Open the FlowAccount AI prompt set, multi-company tab, and pick the tool you use.
2. In Set 02, copy the card for each company's Project instructions, and replace the company name and connector name in square brackets with that company's.
3. Create a Project for that company and paste it into the instructions field. In Claude: Projects → New project → Edit instructions. In ChatGPT: Projects → create a new Project → settings page, instructions field. You do not need to add a connector to the Project, because connectors belong to the AI account.
4. In the Project's first chat, paste the card for the check before work, after creating the Project and adding the connector. The AI must answer with the company that matches the Project. If it does not match, it stops and pulls no numbers.

Grok Bot has no Projects, so only the card for the check before work, after adding all accounts, applies. Paste it into the chat before you start.

When we tested on Claude Free with the Sonnet 5.5 model (Oct 28, 2026, 1 try each), the check message reported the company for both connectors. When we asked for another company's data, the AI refused, and in a Project set up with the wrong company, the AI stopped without pulling numbers. We have not tried ChatGPT or Grok yet. This instruction is an agreement the AI follows, not a lock.

Part 6Limits of what we tested

• Few test runs. The most was 4 chats of general questions on ChatGPT; everything else was 1 to 2 tries. This is what we saw, not a guarantee.
• Tested on October 25 and 28, 2026, with test companies only.
• These apps change fast. Menus or behavior may already differ, which is one more reason to ask which company before every piece of work.

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