AI Expense Tracker MCP Server

A lightweight AI-powered expense tracking backend that allows Claude Desktop to manage expenses using natural language through the Model Context Protocol (MCP).

Example prompts a user can give Claude:

• “Add an expense of 200 for groceries today.”
• “Show my expenses this week.”
• “How much did I spend on food?”

Claude converts these prompts into MCP tool calls, which are handled by this Python server and stored in a PostgreSQL database.

Project Environment

This project was developed and tested on Windows.

The MCP server can run using either:

1. Global Python environment
2. Virtual environment (.venv)

Both approaches are supported depending on your setup.

Project Architecture

Claude Desktop ↓ Remote MCP Server (FastMCP Cloud) ↓ Async Python Tools ↓ Neon PostgreSQL Database

Project Structure

expense-tracker-mcp-server

• main.py → MCP server and tool registration

• dbConnection.py → asynchronous database connection logic

• tools/

  • addExpense.py
  • getExpenses.py
  • totalExpenses.py
  • deleteExpense.py
  • rangeExpenses.py
  • summary.py

Database Schema

Table: expenses

Columns:

• id (primary key)
• date
• amount
• category
• subcategory
• note

Example:

CREATE TABLE expenses (
 id SERIAL PRIMARY KEY,
 date DATE,
 amount NUMERIC,
 category VARCHAR(100),
 subcategory VARCHAR(100),
 note TEXT
);

Development Journey

1. Initial Local MCP Server

The project began as a local MCP server using FastMCP with a PostgreSQL database.

Tools were implemented for:

• Adding expenses
• Retrieving expenses
• Deleting expenses
• Viewing summaries

The database connection was handled using psycopg2.

2. Code Refactoring

A separate module dbConnection.py was created to manage database connections so that all tools could reuse the same connection logic.

This improved code maintainability and avoided duplication.

3. Converting to Asynchronous Server

The original implementation was synchronous, which blocked the server during database operations.

To improve performance and scalability:

• psycopg2 was replaced with asyncpg
• All database functions were converted to async functions
• A PostgreSQL connection pool was implemented

This allows multiple MCP tool requests to run concurrently.

4. Migrating to Cloud Database

Since the server was later deployed remotely, the local database could not be used.

The project migrated to Neon PostgreSQL, a serverless cloud database.

Environment variables were configured in the deployment environment to connect securely.

5. Remote MCP Server Deployment

The MCP server was deployed using FastMCP Cloud.

The GitHub repository was connected to the platform so that:

• Every commit automatically triggers a new deployment
• The MCP endpoint stays updated with the latest code

6. Connecting Claude Desktop

The deployed MCP server requires authentication.

Claude Desktop was connected using the .dxt integration file, which automatically configures the MCP server connection.

Setup

Option 1 — Using a Virtual Environment (Recommended)

Create environment: python -m venv .venv

Activate (Windows): .venv\Scripts\activate

Install dependencies: pip install fastmcp asyncpg

Option 2 — Using Global Python Environment

Install dependencies globally: pip install fastmcp asyncpg

Running the Server Locally

Start the MCP server: python main.py

Restart Claude Desktop after updating MCP configuration.

Tools Available

• add_expense → Add a new expense
• get_expenses → Retrieve all expenses
• total_expenses → Calculate total spending
• delete_expense → Remove an expense
• range_expenses → Expenses within a date range
• summary → Category-wise spending summary

Tech Stack

• Python
• FastMCP
• asyncpg
• PostgreSQL
• Neon Database
• Claude Desktop
• Model Context Protocol (MCP)

Key Takeaways

• MCP enables AI assistants to interact with real systems using structured tools.
• Asynchronous database access significantly improves MCP server scalability.
• Cloud deployment requires environment variables and a remote database.
• Proper separation of database logic and tool logic improves maintainability.