> For security, other than what the MCP protocol itself provides, what should be defined?

The MCP protocol itself provides no security at all.

The MCP specification includes no specified method of authorization, and no specified security rules. It lists a handful of "principles," and then the specification simply gives up on discussing the problem further.

https://modelcontextprotocol.io/specification/2025-11-25#sec...

    3.2 Implementation Guidelines

    While MCP itself cannot enforce these security principles at the protocol
    level, implementors **SHOULD**:

    1. Build robust consent and authorization flows into their applications
    2. Provide clear documentation of security implications
    3. Implement appropriate access controls and data protections
    4. Follow security best practices in their integrations
    5. Consider privacy implications in their feature designs