Cache MCP Results Safely

The protocol now provides cache hints for list/read results, but application tools may also benefit from domain caching.

Good candidates

• Stable tool/resource catalogs.
• Public documentation.
• Expensive read-only reference data.

Risky candidates

• Permission-dependent records.
• Highly volatile state.
• Tool calls with side effects.

Authorization-aware keys

If output depends on user, tenant, role, or scope, include that context in cache keys and prefer private caches.