SEP-2322 is a draft protocol change from the MCP Transports Working Group that would allow a single MCP request to span multiple round trips between client and server. Today, MCP interactions are essentially one-shot: a client sends a request, the server responds, and the exchange is closed. This proposal breaks that constraint, enabling servers to pause mid-execution and ask for additional input before completing — a fundamental shift in how the protocol models interaction.
For designers, the practical implication is that human-in-the-loop patterns like approval, interruption, and clarification can now be modeled at the transport layer rather than bolted on top. Instead of UX teams inventing ad hoc mechanisms for mid-task pauses — or product teams shipping agents that barrel through without checkpoints — the protocol itself would have a sanctioned way to say 'I need something from the human before I continue.'
This is marked as a breaking change, which means it carries real migration costs and signals that the MCP ecosystem is still in active formation. Teams building on MCP today should treat this as a leading indicator: the infrastructure is catching up to the interaction models practitioners already need, but the path there involves protocol churn.