MCP Dev Summit Bengaluru 2026

Most MCP servers are one-shot: the client asks, the server answers. But some features need the server to reason mid-execution like summarise a diff before returning it, classify input to pick the next step, recover from ambiguity instead of failing, generating new data. That's what sampling unlocks: the server calls back into the host's LLM, without ever holding its own model keys.

This deep dive walks through sampling/createMessage feature provided by the mcp protocol and its internals messages, modelPreferences, includeContext, systemPrompt — and what the client is actually allowed to modify. We'll cover capability negotiation and the human-in-the-loop approval flow, then step through how sampling patterns are actually built in the smartbear-mcp server, using its implementations over there to understand how one could build their own sampling features.

Then the hard parts: agent loops, token-budget blowups, portability across clients using different model providers.

You'll leave knowing when sampling beats tools or elicitation, and with patterns you can lift today.