https://sync.day/mcp/mcp
answers a handshake
curl -s -X POST https://sync.day/mcp/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"you","version":"0"}}}'