What happened. The Core v1.1 draft adds typed return values for tool calls and explicit model sampling controls. Backward compatible with v1.0.

This is a significant development for the MCP ecosystem. Teams building on MCP should review the changes and plan accordingly.

What this means

For server authors, this opens new integration patterns. For client authors, it signals continued ecosystem momentum. For end users, it means more capable agent workflows.

What you should do