MCP server-sent-events stream

Long-lived text/event-stream connection. The server pushes JSON-RPC responses + asynchronous notifications down this stream; the client posts requests on /mcp/messages. Sessions live in Redis with a 15-minute TTL, refreshed on every touch.

Auth: Authorization: Bearer je_live_sk_…. Session ID is issued on the initialize handshake and echoed back in the Mcp-Session-Id response header — include it on every subsequent /mcp/messages POST.

Keep-alive ping every 30 seconds. Reconnect on disconnect; the client resumes by re-sending initialize.

⚠ "Try it" caveat: This is an SSE endpoint. Scalar's in-page request runner is built for one-shot request/response cycles, not long-lived streams — clicking Try it will either hang or dump raw event bytes. Test against this surface with an actual MCP client (Claude Desktop, Cursor, the @modelcontextprotocol/inspector CLI), or follow recipe #5: Connect Claude Desktop.