MCP Sampling: What It Was and Why It Is Deprecated

Sampling allowed an MCP server to ask the client to generate a model completion. This could let a server reuse the host's model access instead of integrating an LLM provider directly.

Why it is deprecated

The 2026-07-28 specification marks sampling as deprecated for new designs. The recommended direction is for applications that need model calls to integrate directly with the appropriate LLM provider API.

Legacy compatibility

Sampling still works in current SDKs for compatibility. If you support older clients or servers, you may need to understand it, but you should avoid making it a dependency in a new architecture.

What about server-to-client input?

The broader protocol also changed how interactive server requests are represented. Multi Round-Trip Requests now allow input-required results to be returned in-band and retried without requiring a permanent bidirectional session.