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MCP Server for Natural Language Invoicing

Overview

An MCP (Model Context Protocol) Server integration for Meister Bill that enables users to create, manage, and send invoices through natural language conversations with AI assistants like Claude.

The Problem

Creating invoices traditionally requires:

  • Opening the invoicing software
  • Navigating through multiple forms
  • Manually entering customer details
  • Adding line items one by one
  • Calculating totals and taxes
  • Generating and sending the invoice

This process is time-consuming and breaks workflow, especially when you're already working in an AI chat interface.

The Solution

An MCP Server that connects Meister Bill to AI assistants, allowing users to:

  • Create invoices conversationally in natural language
  • Fetch customer and product data automatically
  • Generate professional invoices instantly
  • Send invoices directly to clients

Real-Life Use Cases

Freelance Designer

Scenario: Sarah is a freelance graphic designer chatting with her AI assistant about her week's work.

Conversation:

Sarah: "I just finished the logo redesign project for Acme Corp. Can you invoice them for the 40 hours we agreed on?"

AI: "I'll create an invoice for Acme Corp. Let me pull up their details... I see they're registered as a business client with the billing address on file. The logo redesign package is €75/hour. Should I create an invoice for 40 hours at €75/hour (€3,000 total plus applicable taxes)?"

Sarah: "Yes, and add a 10% early completion bonus."

AI: "Done! Invoice #2024-156 created for €3,300 plus 19% VAT (€627), total €3,927. Should I send it to their finance contact at billing@acmecorp.com?"

Sarah: "Please do, and set payment terms to 14 days."

AI: "Invoice sent! Payment due by March 28, 2024."

Consulting Agency

Scenario: Marcus runs a small consulting firm and needs to bill multiple clients at month-end.

Conversation:

Marcus: "It's end of month. Create invoices for all my active consulting projects."

AI: "I found 5 active projects with unbilled hours:

  • TechStart Inc: 32 hours consulting
  • Blue Ocean Partners: 45 hours consulting + 12 hours training
  • Green Solutions: 28 hours consulting
  • Metro Bank: 52 hours consulting (premium rate)
  • Local Bakery: 8 hours basic consulting

Should I create invoices for all of them using their standard rates?"

Marcus: "Yes, but give Blue Ocean Partners a 15% discount on the training hours."

AI: "Creating invoices now... Done! 5 invoices generated totaling €47,385. Would you like me to send them all or review them first?"

Marcus: "Let me see the Metro Bank one first."

AI: "Invoice #2024-187 for Metro Bank:

  • 52 hours @ €150/hour (premium rate): €7,800
  • VAT (19%): €1,482
  • Total: €9,282
  • Payment terms: 30 days
  • Due: April 30, 2024"

Marcus: "Perfect. Send all five."

E-commerce Shop Owner

Scenario: Linda sells handmade crafts and needs to create a custom invoice for a bulk order.

Conversation:

Linda: "A corporate client wants to order 50 wooden coasters and 25 ceramic mugs for their office. Can you create a quote?"

AI: "I'll create an invoice for:

  • 50x Wooden Coasters (€8 each): €400
  • 25x Ceramic Mugs (€15 each): €375
  • Subtotal: €775

This is a bulk order. Would you like to apply your standard 20% bulk discount?"

Linda: "Yes, and add shipping for €25."

AI: "Updated invoice:

  • Products: €775
  • Bulk discount (20%): -€155
  • Shipping: €25
  • Net total: €645
  • VAT (19%): €122.55
  • Total: €767.55

Should I mark this as a quote or final invoice?"

Linda: "Make it a quote for now. They're a new customer - save their details as 'Corporate Office Solutions'."

AI: "Quote #2024-Q089 created and customer 'Corporate Office Solutions' added to your database. Would you like me to email them the quote?"

Software Developer

Scenario: Alex is a software developer working on multiple projects simultaneously.

Conversation:

Alex: "I need to bill my client for this month's retainer plus the extra hours I worked on the emergency bug fix."

AI: "Looking at Digital Dynamics Inc... I see they have a monthly retainer of €2,500. How many extra hours did you work on the bug fix?"

Alex: "It was about 12 hours over the weekend."

AI: "I'll create an invoice with:

  • Monthly Retainer (March 2024): €2,500
  • Emergency Support - 12 hours @ €125/hour: €1,500
  • Subtotal: €4,000
  • VAT: €760
  • Total: €4,760

Should I note this was weekend emergency work?"

Alex: "Yes, add a note about the critical production bug fix on March 15-16."

AI: "Invoice created with notes. Their usual payment method is bank transfer within 7 days. Send it now?"

Alex: "Yes, send it."

Plumber (Mobile Use Case)

Scenario: Thomas is a self-employed plumber driving home after fixing a burst pipe at a customer's house. He's using voice-to-text on his phone to chat with his AI assistant while stuck in traffic.

Conversation:

Thomas: "Hey, I just finished at Mrs. Schmidt's place. Need to invoice her for the emergency repair."

AI: "I'll create an invoice for Mrs. Schmidt at Hauptstraße 45. What work did you do?"

Thomas: "Replaced the burst pipe under the kitchen sink. Took about 3 hours including cleanup. Used one standard pipe section and some fittings."

AI: "Got it. Let me calculate:

  • Emergency Plumbing Service - 3 hours @ €85/hour: €255
  • Pipe section (40cm standard): €18
  • Pipe fittings kit: €12
  • Subtotal: €285
  • VAT (19%): €54.15
  • Total: €339.15

Should I add your emergency call-out fee since this was urgent?"

Thomas: "Yes, it was a Sunday emergency call."

AI: "Updated:

  • Emergency Call-Out Fee (Sunday): €75
  • Emergency Plumbing Service - 3 hours: €255
  • Materials: €30
  • Subtotal: €360
  • VAT (19%): €68.40
  • Total: €428.40

Her payment terms are usually immediate or within 7 days. Which should I set?"

Thomas: "Make it immediate payment. She wanted to pay right away but I didn't have the invoice ready."

AI: "Invoice #2024-892 created with immediate payment terms. Should I email it to her at schmidt.maria@gmail.com?"

Thomas: "Perfect, send it. Also add a note thanking her for the coffee."

AI: "Done! Invoice sent with your note. I've also logged this as a completed job in your calendar."

Why this matters for craftsmen:

  • Hands-free operation: Create invoices while driving using voice
  • Immediate billing: Invoice while details are fresh in memory
  • Better cash flow: Send invoices immediately, get paid faster
  • No paperwork: No need to wait until evening to do admin work
  • Professional image: Customers receive invoices within minutes

Technical Features

MCP Server Tools

The MCP Server would expose these tools to AI assistants:

  1. list_customers - Search and retrieve customer information
  2. get_customer - Get detailed customer data
  3. list_products - Browse available products/services
  4. get_product - Get product details and pricing
  5. calculate_invoice - Calculate totals with taxes and discounts
  6. create_invoice - Generate a new invoice
  7. send_invoice - Email invoice to customer
  8. list_invoices - View recent invoices
  9. get_invoice - Retrieve invoice details
  10. update_invoice - Modify draft invoices
  11. add_payment - Record a payment against an invoice

Natural Language Processing

The AI assistant handles:

  • Intent recognition (creating invoice, sending quote, etc.)
  • Entity extraction (customer names, amounts, dates)
  • Context awareness (remembering previous conversations)
  • Validation and confirmation before sending
  • Handling ambiguity and asking clarifying questions

Security & Access Control

  • Authentication via API tokens
  • Feature-based permissions (same as existing Meister Bill)
  • Read-only mode for queries
  • Confirmation required for sending invoices
  • Audit logging of all MCP actions

Benefits

For Users

  • Speed: Create invoices in seconds, not minutes
  • Convenience: Work within your natural workflow
  • Accuracy: AI validates data and calculations
  • Context-aware: AI remembers your preferences and patterns
  • Multi-tasking: Create invoices while discussing other topics

For Business

  • Increased productivity: Faster invoicing = faster payment
  • Reduced errors: Automated data retrieval and validation
  • Better cash flow: Easier to invoice immediately after work
  • Accessibility: Invoice from anywhere using just chat
  • Competitive advantage: Cutting-edge technology

Implementation Phases

Phase 1: Read-Only Access

  • Browse customers and products
  • View existing invoices
  • Calculate invoice totals
  • Generate preview PDFs

Phase 2: Invoice Creation

  • Create draft invoices
  • Save customer information
  • Add products and line items
  • Apply discounts and taxes

Phase 3: Full Integration

  • Send invoices via email
  • Record payments
  • Generate reports
  • Automated follow-ups

Example MCP Server Configuration

{
  "mcpServers": {
    "meisterbill": {
      "command": "bun",
      "args": ["run", "mcp-server"],
      "env": {
        "MEISTERBILL_API_URL": "https://api.meister-bill.com",
        "MEISTERBILL_API_TOKEN": "your-api-token"
      }
    }
  }
}

Competitive Advantage

While other invoicing tools require manual input or complex integrations, Meister Bill's MCP Server would be the first invoicing solution with true conversational AI integration, making it the natural choice for:

  • AI-native businesses
  • Tech-savvy freelancers
  • Modern consulting firms
  • Anyone using Claude or other AI assistants daily

Future Possibilities

  • Voice-activated invoicing (via AI assistants)
  • Automated invoice creation based on time tracking
  • Smart suggestions based on past patterns
  • Multi-language support in conversations
  • Integration with calendar for recurring invoices
  • Automated payment reminders via AI

Conclusion

The MCP Server for Meister Bill transforms invoicing from a tedious administrative task into a natural conversation. By meeting users where they already work—in their AI assistant—we eliminate friction and make billing effortless.

This isn't just about automation; it's about reimagining how business owners interact with their financial tools in an AI-first world.