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Use CADbyAI with your own API key

If you run Claude with your own API key instead of a Claude subscription, you can still use CADbyAI. The connector is a local program, so an app that can start local MCP servers can load it. A user confirmed it with Claude Desktop in Developer mode; Claude Code is not tested yet.

1. Who this is for

You pay for the AI through an API key (for example Claude Desktop in Developer mode with a custom API key, or Claude Code in a terminal) and you want CADbyAI to control SolidWorks.

First install CADbyAI. The installer writes the connector into the normal Claude Desktop config, but Developer mode uses a separate config file, so you add the connector there by hand.

2. Claude Desktop in Developer mode

  1. 1
    Open the normal Claude Desktop config file claude_desktop_config.json (the installer wrote it) and copy the solidworks entry under mcpServers.
  2. 2
    In Claude Desktop open Settings → Developer → Edit Config.
  3. 3
    Paste the entry inside mcpServers of that file (at the beginning if it already has entries) and save. The entry to paste looks like this:
  4. 4
    Set SW_MCP_ROOT to a real folder on your PC: the working folder where Claude may write files and run macros.
  5. 5
    Restart Claude Desktop completely.

"solidworks": { "command": "C:\\CADbyAI\\sw_mcp\\sw_mcp_server.exe", "args": [], "env": { "SW_MCP_ROOT": "C:\\CADbyAI_Work" } }

The Developer mode (third-party) config is different from the normal app config, so it must be edited by hand. In JSON every backslash in a Windows path is written twice, as in the example.

3. Claude Code (terminal)

Claude Code can also start local MCP servers. Add the same program with claude mcp add, using the path of sw_mcp_server.exe and the SW_MCP_ROOT folder from your config. This has not been tested yet: please tell us how it goes.

claude mcp add solidworks --env SW_MCP_ROOT="C:\CADbyAI_Work" -- "C:\CADbyAI\sw_mcp\sw_mcp_server.exe"

4. Check that it works

Restart the app, then ask Claude:

Run license_info

You should see your machine code and the days left. The free 30-day trial starts by itself, exactly as in the normal install.

5. Quick answers

The tools do not appear

Restart the app completely. Check the path of sw_mcp_server.exe and that every backslash is doubled in JSON. If it still fails, that mode may not load local MCP servers, and we cannot change that.

Do I need a Claude subscription?

No. CADbyAI works with the AI app you use, and your API key pays for the AI model (billed by usage, separately from CADbyAI). CADbyAI has its own free 30-day trial and a monthly plan (how subscribing works).

Is this officially supported?

It has been confirmed by a user, not tested by us on every setup. Tell us what you see: [email protected].