Streamable HTTP in MCP

Okay, so normally when we’re talking about streaming, some of you might think of how you divide up files in chunks or how you have AI models return their response in smaller parts. However, in the context of MCP, streaming is more about how we transmit data over HTTP while following the streamable standard, meaning that clients using Streamable HTTP typically send the following Accept header: Accept: application/json, text/event-stream.

This tells the server the client can handle both batch JSON responses and streamed events (via SSE). The server can choose the appropriate response mode based on the request type and context.

Is that it, streaming that just sends simple responses? There’s a bit more to it, namely, resumability.