How to add Locus MCP servers to Cursor

Setup, step by step

1. Step 1

   Create a Locus Pro account

   Sign up at paywithlocus.com/pro. The Free plan has no subscription. Paid calls use prepaid credits.

2. Step 2

   Open the install link

   With Cursor installed, click the button and choose Install in Cursor. The link carries the server config from the next step in base64.

   Add Locus to Cursor

3. Step 3

   Or edit mcp.json by hand

   Paste this into ~/.cursor/mcp.json to use Locus in every project, or .cursor/mcp.json for one project.

   {
     "mcpServers": {
       "locus-pro": {
         "url": "https://api.paywithlocus.com/api/credits/mcp"
       }
     }
   }

4. Step 4

   Approve Locus

   In Cursor’s MCP settings, enable locus-pro and choose Connect. Cursor discovers OAuth and opens Locus Pro. Approve Locus in your browser.

5. Step 5

   Check the connection

   Open Agent chat and ask: What’s my Locus balance?

Should I use the install link or edit mcp.json?

Use the install link. It writes the same locus-pro entry to ~/.cursor/mcp.json for you, and it is the path we tested with OAuth and a live tool call.

Edit the file by hand when you want Locus in one project only, or when links from the browser do not open Cursor. Leave out headers. OAuth replaces them.

Do I need to install Locus skills in Cursor?

No. The Cursor setup is the MCP server alone. When the agent needs longer instructions, it can call the get_locus_guide tool for the same operating guides.

How do I fix a Cursor MCP authentication error?

Turn locus-pro off and on in MCP settings, then choose Connect again and finish the browser approval.

• Check the url is exactly https://api.paywithlocus.com/api/credits/mcp.
• Remove any headers or auth block from the locus-pro entry.
• Keep one Locus entry across the global and project files so tools are not duplicated.
• Check mcp.json is valid JSON.

What can Cursor’s agent do with Locus?

The agent can search the Locus catalog, read an endpoint schema and price, and run the call against your credits. Examples: search the web with sources, extract a page, find a company, or verify an email.

The core tools are search_apis, describe_api, estimate_cost, execute, get_call_result, and get_balance. You do not need an account with each provider.