Claude Desktop

1. Install Claude Desktop

Download Claude Desktop from Anthropic and finish the normal install first.

2. Enable developer mode

Open Claude Desktop. From the menu, open:

Help -> Troubleshooting -> Enable Developer Mode

Restart Claude Desktop after enabling developer mode.

3. Configure custom inference

Open:

Developer -> Configure custom inference

4. Enter the FHRouter URL and token key

Enter:

Field	Value
Gateway base URL	https://api.fhrouter.com
Gateway API key	your FHRouter token key

Keep the auth scheme on bearer.

5. Apply locally and test safely

Click Apply locally, then start with a short prompt:

Reply with one sentence confirming the model is connected.

Then check FHRouter usage before sending long documents or large coding tasks.

6. Use the Cowork tab, not Code

Claude Desktop's third-party inference gateway currently works from the Cowork tab.

If a user switches to the Code tab, Claude Desktop may show:

Failed to authenticate. API Error: 401 Invalid token

even when the same FHRouter token and endpoint work correctly in Cowork.

Use this setup when testing FHRouter in Claude Desktop:

• open Claude Desktop
• stay on Cowork
• keep the gateway base URL as https://api.fhrouter.com
• keep the same FHRouter token key
• if Cowork works but Code fails, treat it as a Claude Desktop client limitation rather than an FHRouter token problem

Common issues

• If the app still shows the normal sign-in flow, confirm developer mode is enabled and restart Claude Desktop.
• If the app rejects the key, re-copy the FHRouter token key from the Token keys page.
• If Cowork works but Code fails with 401 Invalid token, switch back to Cowork. FHRouter accepts the token on the Anthropic endpoint, but Claude Desktop's Code tab may not use the same third-party inference path correctly.
• If the app hangs, retry with a short prompt and check FHRouter usage before sending a larger request.