ynab-mcp

YNAB MCP Server

A comprehensive Model Context Protocol (MCP) server for YNAB (You Need A Budget) that enables AI assistants like Claude Desktop to read your budget, analyze spending patterns, detect subscriptions, and provide personalized financial insights—all through natural conversation.

Why YNAB MCP?

Traditional YNAB integrations require manual API calls or custom scripting. This MCP server lets you:

• Talk to your budget naturally — Ask Claude "Am I overspending on dining out?" and get instant insights
• Get AI-powered financial analysis — Subscription detection, spending trends, savings recommendations, and budget health scores
• Stay safe by default — Read-only mode protects against accidental changes
• Access everything — 66 tools total: comprehensive YNAB API coverage (40 tools), 23 custom analytics tools, and 3 system tools

Features

Feature	Description
Broad API Coverage	66 MCP tools spanning the YNAB API endpoints
Advanced Analytics	23 tools for spending analysis, trend detection, and financial insights
Read-Only by Default	Write operations require explicit opt-in (YNAB_READ_ONLY=false)
Smart Rate Limiting	Token bucket algorithm with 180 req/hour budget (10% safety margin)
Intelligent Caching	Reduces API calls for infrequently changing data
Type-Safe	Full TypeScript implementation with Zod schema validation

Quick Start

Prerequisites

• A YNAB account with API access
• A YNAB Personal Access Token (get one here)

Installation Options

Option 1: npx (Easiest)

No installation required—run directly:

npx ynab-mcp

Option 2: Docker

docker run -e YNAB_ACCESS_TOKEN=your_token ghcr.io/auzroz/ynab-mcp:latest

Option 3: Install from Source

# Clone the repository
git clone https://github.com/auzroz/ynab-mcp.git
cd ynab-mcp

# Install dependencies and build
npm install
npm run build

# Run the server
npm start

Configuration

The server is configured via environment variables:

Variable	Required	Description
YNAB_ACCESS_TOKEN	Yes	Your YNAB Personal Access Token
YNAB_BUDGET_ID	No	Default budget UUID (uses "last-used" if not set)
YNAB_READ_ONLY	No	Set to false to enable write operations (default: true)

Remote / HTTP mode

By default the server speaks stdio (local). Set MCP_TRANSPORT=http to run it as a remote server over the MCP Streamable HTTP transport at POST /mcp, with a plain GET /health for load balancers. Each session gets an isolated client/cache/rate-limiter/audit-log.

Variable	Description
MCP_TRANSPORT	stdio (default) or http
PORT	HTTP port (default 3000)
ALLOWED_HOSTS / ALLOWED_ORIGINS	Comma-separated allowlists for DNS-rebinding protection
ENABLE_DNS_REBINDING_PROTECTION	Enable Origin/Host checks (needs an allowlist)

Multi-user (YNAB OAuth). Configure a YNAB OAuth app + ENCRYPTION_KEY + PUBLIC_URL and the server becomes an OAuth 2.1 Authorization Server federated to YNAB: many users connect their own YNAB accounts to one instance, each isolated, choosing read-only or read-write at consent. See docs/REMOTE_HOSTING.md for the full deployer guide (registering the YNAB app, storage, TLS).

Single-user (header auth). If the OAuth variables aren't all set, HTTP mode takes the YNAB token per request via the X-YNAB-Token header (falling back to YNAB_ACCESS_TOKEN for one user). Serve behind TLS.

MCP_TRANSPORT=http PORT=3000 YNAB_ACCESS_TOKEN=… npm start
# connect an MCP client via the mcp-remote shim:
npx mcp-remote http://localhost:3000/mcp --header "X-YNAB-Token: <your-token>"

Claude Desktop Integration

Add to your Claude Desktop configuration:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

Using npx (Recommended)

{
  "mcpServers": {
    "ynab": {
      "command": "npx",
      "args": ["ynab-mcp"],
      "env": {
        "YNAB_ACCESS_TOKEN": "your_token_here"
      }
    }
  }
}

Using Docker

{
  "mcpServers": {
    "ynab": {
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "YNAB_ACCESS_TOKEN",
        "ghcr.io/auzroz/ynab-mcp:latest"
      ],
      "env": {
        "YNAB_ACCESS_TOKEN": "your_token_here"
      }
    }
  }
}

Using Local Build

{
  "mcpServers": {
    "ynab": {
      "command": "node",
      "args": ["/path/to/ynab-mcp/dist/index.js"],
      "env": {
        "YNAB_ACCESS_TOKEN": "your_token_here"
      }
    }
  }
}

Example Conversations

Once connected, try asking Claude:

Question	Tool Used
"What's my current net worth?"	ynab_net_worth
"How much did I spend on dining out this month?"	ynab_list_category_transactions
"What subscriptions do I have?"	ynab_detect_recurring
"Is my budget in good shape?"	ynab_budget_health
"Where can I cut back on spending?"	ynab_savings_opportunities
"Am I on track this month?"	ynab_spending_pace
"Compare this month to last month"	ynab_monthly_comparison

Available Tools (66 Total)

Analytics Tools (23)

These tools provide AI-powered financial insights beyond basic YNAB functionality:

Tool	Description
ynab_detect_recurring	Find subscription patterns and recurring payments
ynab_spending_analysis	Analyze spending trends by category
ynab_budget_health	Assess overall budget health with score and alerts
ynab_savings_opportunities	Identify potential areas to save money
ynab_budget_vs_actuals	Compare budgeted vs actual spending
ynab_quick_summary	At-a-glance budget status overview
ynab_income_expense	Income vs expense breakdown and trends
ynab_net_worth	Calculate total net worth from all accounts
ynab_goal_progress	Track goal funding progress with projections
ynab_spending_by_payee	Analyze spending by merchant/payee
ynab_unused_categories	Find inactive or unused categories
ynab_monthly_comparison	Month-over-month spending comparison
ynab_spending_trends	Multi-month trend analysis with projections
ynab_cash_flow_forecast	Project future cash flow based on scheduled transactions
ynab_reconciliation_helper	Help with account reconciliation
ynab_budget_suggestions	Get budget suggestions based on history
ynab_overspending_alerts	Quick check for overspent categories
ynab_transaction_search	Powerful multi-filter transaction search
ynab_spending_pace	Track daily spending rate vs target
ynab_category_balances	Quick category balance lookup
ynab_credit_card_status	Credit card balances vs payment categories
ynab_age_of_money	Age of money metric with explanation
ynab_preview_scheduled_transaction	Preview the budget impact of a scheduled transaction

Core YNAB API Tools (40)

Coverage of the YNAB API endpoints:

User Tools (1)

• ynab_get_user — Get authenticated user information

Budget Tools (3)

• ynab_list_budgets — List all accessible budgets
• ynab_get_budget — Get detailed budget information
• ynab_get_budget_settings — Get budget settings (currency format, etc.)

Account Tools (3)

• ynab_list_accounts — List all accounts with balances
• ynab_get_account — Get specific account details
• ynab_create_account — Create a new account (write mode)

Category Tools (7)

• ynab_list_categories — List all category groups and categories
• ynab_get_category — Get category details
• ynab_get_month_category — Get category budget for specific month
• ynab_update_category — Update category budgeted amount (write mode)
• ynab_create_category — Create a new category in a group (write mode)
• ynab_create_category_group — Create a new category group (write mode)
• ynab_update_category_group — Rename a category group (write mode)

Payee Tools (7)

• ynab_list_payees — List all payees (merchants/vendors)
• ynab_get_payee — Get specific payee details
• ynab_create_payee — Create a new payee (write mode)
• ynab_update_payee — Rename a payee (write mode)
• ynab_list_payee_locations — List all payee locations for mapping
• ynab_get_payee_location — Get specific payee location
• ynab_list_payee_locations_by_payee — List locations for a specific payee

Month Tools (2)

• ynab_list_months — List all budget months
• ynab_get_month — Get detailed month summary with categories

Transaction Tools (11)

• ynab_list_transactions — List transactions with filters
• ynab_get_transaction — Get transaction details
• ynab_create_transaction — Create a new transaction (write mode)
• ynab_create_transactions — Bulk create transactions (write mode)
• ynab_update_transaction — Update a transaction (write mode)
• ynab_update_transactions — Bulk update transactions (write mode)
• ynab_delete_transaction — Delete a transaction (write mode)
• ynab_list_account_transactions — List transactions for a specific account
• ynab_list_category_transactions — List transactions for a specific category
• ynab_list_payee_transactions — List transactions for a specific payee
• ynab_import_transactions — Trigger import from linked banks (write mode)

Scheduled Transaction Tools (5)

• ynab_list_scheduled_transactions — List scheduled/recurring transactions
• ynab_get_scheduled_transaction — Get scheduled transaction details
• ynab_create_scheduled_transaction — Create a scheduled transaction (write mode)
• ynab_update_scheduled_transaction — Update a scheduled transaction (write mode)
• ynab_delete_scheduled_transaction — Delete a scheduled transaction (write mode)

Money Movement Tools (1)

• ynab_list_money_movements — List moves of funds between categories

System Tools (3)

• ynab_rate_limit_status — Check API rate limit status
• ynab_audit_log — View write operation audit log
• ynab_health_check — Test API connectivity

Available Prompts

Beyond raw tool access, the server exposes 7 MCP Prompts — guided workflows grounded in YNAB's own budgeting methodology (the Four Rules, Age of Money, True Expenses) that orchestrate several tools into a single review. Any MCP client that supports the prompts capability can invoke them directly.

Prompt	What it does
ynab-pulse-check	Fast daily-style status check
ynab-monthly-review	Full end-of-month budget review and next month's suggested targets
ynab-assign-money	Give Every Dollar a Job — allocate unassigned funds
ynab-true-expenses	Embrace Your True Expenses — plan for irregular/annual costs
ynab-overspending-triage	Roll With the Punches — find and fix overspending
ynab-age-of-money	Age Your Money — check cash cushion and credit card float
ynab-reconcile-cleanup	Weekly hygiene: reconciliation and category cleanup

See docs/REMOTE_HOSTING.md for details.

Skills

Our MCP server gives Claude access to your YNAB budget. Our skills teach Claude YNAB's own best practices — some work standalone, some get sharper when connected. Together, they turn raw budget data into an actual coach.

The skills/ directory has 15 Claude Agent Skills: 7 that orchestrate this MCP server's tools into guided reviews, and 8 standalone coaching skills (getting started, debt payoff, irregular income, windfalls, emergency funds, and more) that work with or without this server connected. Every GitHub Release attaches them as downloadable zips — see skills/README.md for the full list and install instructions.

Development

# Run with hot reload
npm run dev

# Run tests
npm test

# Run tests in watch mode
npm run test:watch

# Lint code
npm run lint

# Fix lint issues
npm run lint:fix

# Type check only
npm run typecheck

Testing with MCP Inspector

npx @modelcontextprotocol/inspector node dist/index.js

Architecture

src/
├── index.ts              # Entry point (selects stdio or http transport)
├── server.ts             # Per-user server + tool registration
├── http.ts               # Express app for remote (Streamable HTTP) mode
├── crypto.ts             # AES-256-GCM at-rest token encryption
├── config/               # Environment configuration
├── auth/                 # Remote OAuth: MCP AS provider, YNAB client, sessions
├── storage/              # Pluggable storage (memory / sqlite / postgres)
├── services/             # Core services
│   ├── ynab-client.ts    # YNAB API wrapper with rate limiting
│   ├── rate-limiter.ts   # Token bucket rate limiter
│   ├── audit-log.ts      # Per-user write audit log
│   └── cache.ts          # In-memory TTL cache
├── tools/                # MCP tool implementations
│   ├── user/
│   ├── budgets/
│   ├── accounts/
│   ├── categories/
│   ├── payees/
│   ├── months/
│   ├── transactions/
│   ├── scheduled-transactions/
│   └── analytics/
└── utils/                # Helpers (currency, dates, errors)

Security

Feature	Description
Read-Only Default	Write operations disabled unless YNAB_READ_ONLY=false
Token Security	Never commit your YNAB_ACCESS_TOKEN; use environment variables
Input Validation	All tool parameters validated with Zod schemas
Rate Limiting	Built-in protection against API quota exhaustion
Audit Logging	All write operations logged for review

Contributing

• Fork the repository
• Create a feature branch (git checkout -b feature/amazing-feature)
• Make your changes
• Run tests and linting: npm test && npm run lint
• Commit your changes (git commit -m 'Add amazing feature')
• Push to the branch (git push origin feature/amazing-feature)
• Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• YNAB for their excellent budgeting platform and API
• Anthropic for Claude and the Model Context Protocol
• Model Context Protocol for the MCP specification

Related Projects

• YNAB API Documentation
• Model Context Protocol
• Claude Desktop

Built with ❤️ for the YNAB community