# sse-polling

SEP-1699 server-initiated SSE disconnection + client reconnection with `Last-Event-ID` replay. **Sessionful 2025** by definition (the feature lives on `NodeStreamableHTTPServerTransport` + an `EventStore`). `eventStore` resumability is a 2025-session concern with no 2026-07-28
per-request equivalent.

The `long-operation` tool emits two log notifications, calls `ctx.http?.closeSSE()` mid-stream, emits two more while the client is disconnected, then returns. The client transport reconnects after `retryInterval` (300 ms) with `Last-Event-ID`; the event store replays the buffered
events. The client asserts the result arrived AND the post-disconnect log was delivered.

```bash
pnpm --filter @mcp-examples/sse-polling server -- --http --port 3001    # term 1
pnpm --filter @mcp-examples/sse-polling client -- --http http://127.0.0.1:3001/mcp    # term 2
```