B1 Developers
The B1 MCP Server, free edition

Installing it in Claude Desktop

It takes about ten minutes. You add one file to Claude Desktop, fill in a short form with your licence key and your Business One details, and then you can start asking questions. There’s nothing else to install.

Before you start

  • Claude Desktop, on Windows or a Mac

    The free edition runs inside the Claude Desktop app, so Claude in a web browser will not do. You can download it from claude.ai/download. If you already have it, update it first: on a Mac, click Claude in the menu bar and choose “Check for Updates…”.

  • Your licence key

    It starts with B1M- and it’s in the email we sent when you registered. If you can’t find it, you can issue a new one on your account page.

  • Your Business One details

    The Service Layer URL, the company database name, and a Business One user name and password. If you don’t know the Service Layer URL, whoever looks after your Business One server will.

  • A connection to your Business One server

    This computer has to be able to reach the Service Layer. If you’re working away from the office, that usually means being on the VPN.

  1. 01

    Download the server

    Sign in to your account page and click Download. You’ll get a file whose name starts with b1-mcp-free and ends in .mcpb, about 260 KB.

    Keep it just as it is. Don’t unzip it, rename it or try to open it. If your browser asks whether to keep the file, keep it.

  2. 02

    Add it to Claude Desktop

    1. Open Claude Desktop’s settings: click your name at the bottom left of the window, and choose Settings from the menu that opens. On Windows the shortcut is Ctrl + comma. On a Mac you can also click Claude in the menu bar at the top of the screen, then Settings….
    2. In the list on the left, under Desktop app, click Extensions. It’s not under Customize further down: Skills, Connectors and Plugins are for other things.
    3. Open your Downloads folder, and drag the .mcpb file onto the Extensions page, where it says “Drag .MCPB or .DXT files here to install”.
    4. Claude Desktop shows what you’re installing, SAP Business One (Free), and asks you to confirm. Click Install.

    If you’d rather not drag the file, click Advanced settings on the same page, then Install extension in the Extension developer section, and choose the file. Claude Desktop shows a “Developer tools warning” there, because that section is meant for people who build extensions. It’s expected for an extension installed from a file.

    Two things that don’t work: double-clicking the file, because most computers don’t know which program opens it, and Browse extensions, which is Anthropic’s directory, where the free edition isn’t listed.

  3. 03

    Fill in the form

    Claude Desktop asks for the extension’s settings. If it doesn’t straight after installing, click Configure beside SAP Business One (Free) on the Extensions page. Fill them in and save.

    Licence keyThe key from your registration email, for example B1M-XXXXX-XXXXX-XXXXX-XXXXX. Paste it exactly as it is.
    Service Layer URLThe address of your Service Layer, with the port and /b1s/v2 at the end, for example https://your-b1-server:50000/b1s/v2.
    Company databaseYour company’s database name, spelt exactly as Business One has it, because capitals matter. For example SBODEMOUS.
    B1 user nameA Business One user. The free edition only ever reads, and it only sees what this user is allowed to see, so a user with read-only permissions is a good choice.
    B1 passwordThat user’s password. Claude Desktop keeps it, and your licence key, in Windows Credential Manager or the Mac Keychain.
    Verify TLS certificateLeave this off if your Service Layer uses the self-signed certificate Business One installs, which most do. Turn it on only if your server has a proper certificate.

    To change any of these later, go back to Settings, then Extensions, and click Configure beside SAP Business One (Free).

  4. 04

    Check it works

    1. Start a new chat in Claude Desktop.
    2. Click the + button at the bottom left of the message box (“Add files, connectors, and more”) and point to Connectors. SAP Business One (Free) should be listed and switched on.
    3. Ask a question about your Business One, for example “Which customers owe us more than 60 days, and how much?”
    4. The first time, Claude asks for your permission to use SAP Business One (Free). Allow it.

    The first time it runs, the server activates your licence with us, and this computer then appears under Installs on your account page.

If something goes wrong

What you might see, and what to do

I can’t find Extensions+
It’s in Settings, in the list on the left under Desktop app, below System. The Customize section further down (Skills, Connectors, Plugins) is not where it goes. If Extensions isn’t there at all, update Claude Desktop and restart it. If your company manages your Claude account (a Team or Enterprise plan), an administrator can switch extensions off, so ask them.
I looked under Customize and couldn’t install it there+
Customize, with Skills, Connectors and Plugins, is for other kinds of add-ons, so the file can’t be installed from there. The free edition is an extension: in Settings, click Extensions in the Desktop app group higher up the list, and drag the file onto that page, as in step 2.
Double-clicking the file does nothing, or opens the wrong program+
That’s expected on most computers, because they don’t know which program opens a .mcpb file. Drag it onto Settings, Extensions instead, as in step 2.
Claude says “A free licence key is required”+
The licence key is missing. In Settings go to Extensions, click Configure beside SAP Business One (Free), paste the key and save.
Claude says the licence is already active on 2 installs+
Each licence covers two computers. Release one you no longer use on your account page, then ask your question again.
Claude says “Could not connect to SAP Business One”+
Check the Service Layer URL, company database, user name and password in the extension’s settings, and check this computer can reach the server. A quick test is to open the Service Layer URL in a web browser on this computer. A warning about the certificate is normal, but if the page can’t be reached at all, neither can the server, so check the VPN or ask whoever looks after the server.
Claude says it could not reach b1developers.com+
The first time it starts, the server checks your licence with us, so the computer needs to be online. After that it keeps working for about six weeks without reaching us.
Claude answers without looking at my Business One+
Check SAP Business One (Free) is switched on under the + button, then Connectors. Start a new chat, and mention Business One in your question.
None of this has helped+
Email info@b1developers.com with what you see. If you can, attach Claude Desktop’s log files, the ones whose names start with mcp. On a Mac they’re in ~/Library/Logs/Claude, and on Windows in %APPDATA%\Claude\logs.

Claude Desktop is made by Anthropic, and its menus can move between versions. If something here doesn’t match what you see, tell us at info@b1developers.com and we’ll fix it. The B1 MCP Server is an independent product by B1 Developers and is not endorsed by or affiliated with SAP SE. SAP and SAP Business One are trademarks of SAP SE.