MCP authentication - MailKatana Docs

MailKatana authenticates every MCP transport request before it reaches the MCP server.

Required header

Authorization: Bearer YOUR_API_KEY

The server validates the key on every Streamable HTTP request and binds the tool call to the owning workspace. Clients must include the header on initialize, notifications, tool discovery, tool calls, and session termination requests.

Important behavior

Authentication is not passed as a tool argument.
A direct request to /mcp or the legacy /mcp/sse endpoint without the header should return 401; that means the endpoint is live but the request is unauthenticated.
A missing Bearer token returns 401 with Authorization header with Bearer token required.
An inactive or unknown key returns 401 with invalid API key.

Verification command

curl -i -X POST https://api.mailkatana.com/mcp \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  --data '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"curl","version":"1.0"}}}'

Use this when a client configuration is failing and you want to separate auth or transport issues from client-specific setup problems.