How to integrate Ynab MCP with Codex

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Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Ynab MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

Also integrate Ynab with

Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 1000+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install Ynab MCP in Codex

Run the setup command

Run this command in your terminal to add the Composio MCP server to Codex.

Terminal

It will initiate the authentication in a browser window, authorize Codex to access your Composio account.

Composio authentication page

(Optional) Authenticate with OAuth

To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.

bash
codex mcp login composio

Verify the connection

Run codex mcp list to confirm Composio appears as a registered MCP server.

bash
codex mcp list

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
  2. Fill the header and Key fields with { "x-consumer-api-key" = "ck_*******" }.
  3. The Key is the Composio API key, that you can find on dashboard.composio.dev
  4. Click on Authenticate and authorize Codex to your Composio account and you're all set.
Codex App MCP setup
  1. Restart and verify if it's there in .codex/config.toml
bash
[mcp_servers.composio]
url = "https://connect.composio.dev/mcp"
http_headers = { "x-consumer-api-key" = "ck_*******" }

What is the Ynab MCP server, and what's possible with it?

The Ynab MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Ynab account. It provides structured and secure access to your budgeting data, so your agent can perform actions like tracking expenses, creating and adjusting budgets, fetching transaction history, and analyzing spending patterns on your behalf.

  • Automated transaction tracking: Let your agent fetch, categorize, or summarize recent transactions to keep your spending up to date.
  • Budget creation and adjustment: Instruct your agent to set up new budgets, update existing categories, or reallocate funds between envelopes as your needs change.
  • Spending analysis and reporting: Have your agent analyze your expenses, highlight trends, or generate summaries to help you understand where your money goes.
  • Goal monitoring and progress updates: Ask your agent to track progress toward savings or debt payoff goals, and notify you of milestones or needed adjustments.
  • Account and balance synchronization: Enable your agent to pull up-to-date balances from multiple accounts, ensuring your budget always reflects the latest financial picture.

Supported Tools & Triggers

Tools
Create a new account in a budgetTool to create a new account in a budget.
Create Scheduled TransactionCreates a scheduled (recurring) transaction in a YNAB budget.
Delete Scheduled TransactionPermanently deletes a scheduled transaction from a YNAB budget.
Get Account by IDTool to retrieve a single account resource.
Get Budget By IDRetrieve a complete budget export by ID, including all accounts, categories, payees, and transactions.
Get Budget MonthTool to retrieve a specific budget month.
Get Budget SettingsTool to retrieve budget-level settings.
Get Category by IDRetrieve a single YNAB budget category by its ID.
Get Month Category By IDTool to retrieve a single category for a specific budget month.
Get Payee by IDTool to retrieve a single payee by its ID.
Get Scheduled Transaction by IDTool to retrieve a single scheduled transaction.
Get Transaction by IDTool to retrieve a single transaction by its ID.
Get Authorized UserTool to retrieve the authorized user's information.
List AccountsRetrieves all accounts for a specified YNAB budget.
List BudgetsRetrieves all budgets accessible to the authenticated YNAB user.
List CategoriesTool to list all category groups and their categories for a budget.
List Budget MonthsTool to list months for a budget with summary information.
List Payee LocationsRetrieves all GPS locations associated with payees in a budget.
List Payee Locations by PayeeRetrieves all GPS locations associated with a specific payee in a budget.
List payees in a budgetTool to list payees in a budget.
List Scheduled TransactionsList all scheduled (recurring) transactions for a YNAB budget.
List TransactionsTool to list transactions in a budget.
List Transactions by AccountTool to list transactions for a specific account.
List Transactions by CategoryTool to list transactions for a specific category (excludes pending).
List Transactions by PayeeTool to list transactions for a specific payee in a budget.
Update PayeeTool to update a payee.
Update Scheduled TransactionUpdate an existing scheduled transaction in YNAB.

Conclusion

You've successfully integrated Ynab with Codex using Composio's MCP server. Now you can interact with Ynab directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for Ynab operations
  • Managed authentication through Composio
  • Access to 20,000+ tools across 1000+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various Ynab operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities

How to build Ynab MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and Ynab MCP?

With a standalone Ynab MCP server, the agents and LLMs can only access a fixed set of Ynab tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Ynab and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Codex?

Yes, you can. Codex fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Ynab tools.

Can I manage the permissions and scopes for Ynab while using Tool Router?

Yes, absolutely. You can configure which Ynab scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Ynab data and credentials are handled as safely as possible.

Used by agents from

Context
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Agent.ai
Altera
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Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

Never worry about agent reliability

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