Which connection should you use?
Pick by the Claude you use. Claude Desktop and Claude.ai sign in securely, with no API key. Claude Code, Codex, Cursor and other MCP clients use a Leonar API key. Either way you need a workspace with API access: the Professional plan or an active trial. Viewers cannot connect.
Claude Desktop or Claude.ai: add the connector
Open Settings / Customize > Connectors, choose Add custom connector, and enter https://app.leonar.app/api/mcp. No API key is involved. Do not use the old SSE URL.
Authorize one workspace
Claude finds Leonar OAuth from the endpoint, signs you in, and asks which single workspace the connector may use. There is nothing else to set up.
Claude Code, Codex or Cursor: use an API key
These local clients connect with a Leonar leo_... API key, over Direct HTTP Bearer auth or the local @leonar/mcp NPX bridge.