Skip to main content
Common issues and solutions for the LeadMagic MCP server.

Quick Diagnostics

Ask your AI assistant: “Check my LeadMagic credit balance.”
  • Works? Your connection and authentication are fine.
  • Doesn’t work? Follow the troubleshooting steps below.

Connection Issues

Symptoms: AI assistant doesn’t recognize LeadMagic tools, “no tools available,” or server appears disconnected.Solutions:
  1. Verify the URL — ensure your config uses exactly https://mcp.leadmagic.io/mcp (note the /mcp path).
  2. Restart your client — most MCP clients require a restart after config changes:
    • Cursor: Restart the application
    • VS Code: Run Developer: Reload Window
    • Claude Desktop: Fully quit and reopen
    • Windsurf: Restart the application
  3. Check JSON syntax — a missing comma or bracket in your config file will silently fail. Validate your JSON at jsonlint.com.
  4. Check the config file location — make sure you’re editing the right file for your client (see setup guide).
Symptoms: Tools take a long time to respond or time out entirely.Solutions:
  1. Check your internet connection — the MCP server runs at mcp.leadmagic.io and requires internet access.
  2. Try the health endpoint — run this in your terminal to verify the server is reachable:
curl https://mcp.leadmagic.io/health
You should see {"ok":true,"service":"lm-mcp",...}.
  1. Rate limits — the LeadMagic API has rate limits. If you’re making many rapid requests, you may be temporarily throttled.

Authentication Errors

Cause: Missing or invalid API key.Solutions:
  1. Check the header name — it must be x-leadmagic-key (lowercase), not X-API-Key or Authorization.
  2. Verify your key — log in to app.leadmagic.io/settings/api and copy a fresh key.
  3. Check for whitespace — ensure there are no trailing spaces or newlines in your API key value.
  4. Check the key prefix — valid LeadMagic API keys start with lm_.
Cause: Your account has no remaining credits.Solutions:
  1. Check your balance at app.leadmagic.io.
  2. Purchase credits or set up auto top-up.
  3. See Credits & Pricing for plan options.

Client-Specific Issues

Cursor

Config not picked up:
  • Ensure the file is at .cursor/mcp.json (project) or ~/.cursor/mcp.json (global).
  • Restart Cursor after any config change.
Multiple configs:
  • Project-level config (.cursor/mcp.json) takes priority over global (~/.cursor/mcp.json).
  • If you have both, the project-level config wins.

Tool Errors

MCP tool errors are returned as isError: true with a message. Common causes:
  • Missing required parameters — check the tool reference for required fields.
  • Invalid parameter format — emails must be valid format, LinkedIn URLs must be full URLs (e.g., https://linkedin.com/in/username).
  • API rate limit — wait a moment and try again.
A not_found result means LeadMagic doesn’t have data for that query. This is free — no credits are charged.Tips to improve results:
  • Use domain instead of company_name for company lookups.
  • Use LinkedIn profile URLs when available — they’re the most reliable identifier.
  • For find_email, provide both first and last name plus the company domain.

FAQ

No. Your API key is sent on every request via the x-leadmagic-key header and is never persisted. The server is fully stateless.
Yes, but each person using the key consumes credits from the same account. For team usage, consider using separate keys or an organization account with shared credits.
They use the same underlying API. The MCP server wraps each API endpoint as an MCP tool so AI assistants can call them directly. Credit costs are identical. If you need programmatic access from your own code, use the REST API directly.
No. The server uses Streamable HTTP transport only (MCP 2025 spec). There is no SSE endpoint. Most supported clients work with Streamable HTTP natively. Claude Desktop and Zed use mcp-remote to bridge the transport.
Not currently. ChatGPT requires OAuth 2.1 authentication for MCP servers, which this server does not implement. Use the REST API with ChatGPT’s custom GPT actions instead.

Still Need Help?