AI Agent for Invoice and Expense Tracking

I am looking for an experienced freelancer to build an AI agent for my client, a company that manages construction projects. The AI agent should: Receive invoices as PDF files or images. Extract details such as the supplier’s name, invoice number, date, amount, VAT and expense category. Assign each expense to the correct construction project. Ask follow-up questions through chat when information is missing or unclear. Save and categorize the information in a central database, such as Google Sheets or another suitable platform. Allow users to request reports through chat, including expenses, income, and profit and loss by project, category or date range. Provide an interface where users can view, edit and update the information manually without using the chat. I am considering WhatsApp as the chat interface, but I am open to other recommendations. I am also deciding which platform would be best for storing and managing the data. When applying, please include: The tools and technology stack you recommend for this project. The tools you can work with, such as n8n, Make, WhatsApp API, OCR and document-processing tools, AI models, Google Sheets, Airtable or a custom database. Examples of AI agents, invoice-processing systems or similar projects you have built, including the tools you used. Your suggested approach for handling missing information, classifying invoices and assigning expenses to projects. Whether you recommend starting with a small MVP and what you think it should include. Best regards, Avraham