I Built an MCP Server for My ERP — Here's What I Learned

There's a new way to manage a business. Not an app, not a dashboard, not another browser tab. You talk to your AI assistant and it accesses your invoices, expenses, and clients directly. I built Frihet , an AI-native ERP for freelancers. When Anthropic released the MCP protocol, I knew the ERP needed to speak it natively. So I built an MCP server. Here's what I learned. What the MCP Server Does 31 tools across 6 resources: Resource Operations Invoices Create, read, update, delete, search, list Expenses Create, read, update, delete, list Clients Create, read, update, delete, list Products Create, read, update, delete, list Quotes Create, read, update, delete, list Webhooks Create, read, delete, list In practice, you tell Claude: "Create an invoice for Acme Ltd for 2,500 EUR for January consulting" The invoice is created with correct tax details, VAT calculated, and invoice number assigned. No browser needed. Architecture User → AI Assistant (Claude/Cursor) ↓ MCP Protocol @frihet/mcp-ser