MCP Server

Overview

The 50c MCP server exposes all 101+ tools to MCP-compatible clients like Cursor, Claude Desktop, and Windsurf.

Installation

Cursor

1. Open Settings → Features → Model Context Protocol
2. Click “Add Server”
3. Enter configuration:

{
  "50c": {
    "command": "npx",
    "args": ["-y", "50c"],
    "env": {
      "FIFTYC_API_KEY": "cv_YOUR_KEY"
    }
  }
}

Claude Desktop

Edit claude_desktop_config.json:

macOS

Location: ~/Library/Application Support/Claude/claude_desktop_config.json

Windows

Location: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "50c": {
      "command": "npx",
      "args": ["-y", "50c"],
      "env": {
        "FIFTYC_API_KEY": "cv_YOUR_KEY"
      }
    }
  }
}

Windsurf

1. Open Settings → Cascade → MCP Servers
2. Add server configuration

Available Tools

All 101+ 50c tools are available. See Tools for complete list.

Popular tools:

• genius — Deep problem solving
• roast — Code review
• bcalc — Math exploration
• web_search — Web search
• hints — Quick hints

Environment Variables

Variable	Required	Description
FIFTYC_API_KEY	Yes	Your 50c API key (cv_*)
FIFTYC_BASE_URL	No	Custom API endpoint

Troubleshooting

Tools not appearing

1. Check your API key is set correctly
2. Restart Cursor/Claude Desktop
3. Check the console for errors

”insufficient_credits” error

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Rate limiting

Pro plans have higher rate limits. Contact support for enterprise needs.