Lead Accounting Plus MCP server (official ModelContextProtocol C# SDK)
MCP endpoint: /mcp (Streamable HTTP, JSON-RPC 2.0)

Auth (preferred): OAuth 2.1 — connect from an MCP client and you will be
  taken to a Lead sign-in page. Discovery: /.well-known/oauth-protected-resource

Auth (alternatives): X-Lead-* headers, ?comid=..&comkey=..&userid=..&password=..
  on the URL, or LEAD_* environment variables (single-tenant).