"Proton Calendar" matching MCP connectors:

Real public holiday lookup for 206 countries via a rule-based calendar engine. Paid via x402.

Japanese holiday and business-day calculations using official Japan Cabinet Office data.

Japan data tools for AI agents: calendar (rokuyo), address, name splitting, corporate number lookup

17+ Japan MCP tools (weather/calendar v2/local-pack/enrich). x402 on Base, wallet-free trial.