Do I need tools? Do I need MCP?

• Use narrow tools for fresh data and actions.
• MCP is useful when approved hosts need a shared discoverable integration, not merely because the model has one function call.
• Keep the existing business API behind either a direct wrapper or the MCP facade.

Authority: caller identity, tenant, permission, and approval must be established independently of model arguments. A tool should expose a business capability, not arbitrary database or network power.