Codex app

The Codex desktop app reads the same ~/.codex/config.toml as Codex CLI — there’s no separate app-specific config format, and configuring one surface configures the other.

Connect to a server (OAuth) — recommended

If someone — you, or someone in your household — is running the self-hosted server, this is the recommended way to connect: you log into YNAB with your own account instead of sharing a token. Add its URL instead of a command:

[mcp_servers.ynab]
url = "https://<your-hostname>/mcp"

The app’s OAuth login for MCP servers runs through the same flow the CLI’s codex mcp login triggers — log into YNAB and choose read-only or full access when prompted. If the app doesn’t surface a login prompt automatically, run codex mcp login ynab from a terminal; both share the same config and the same stored credentials.

Alternate: stdio + Personal Access Token

No server to run, but a single token stands in for your own login — the right trade when you’re the only person using this. Add this to ~/.codex/config.toml (by hand, or via codex mcp add from a terminal — see the Codex CLI page for that command):

[mcp_servers.ynab]
command = "npx"
args = ["-y", "@redlinelabs/ynab-mcp"]

[mcp_servers.ynab.env]
YNAB_TOKEN = "your-personal-access-token"
YNAB_BUDGET_ID = "last-used"

Restart the app. See the Quick start for where to get a token.

What it looks like

A real Codex app session against demo mode — a fictional budget, no credentials. Tip: naming YNAB in your prompt (“Check my YNAB budget…”) is the reliable way to get Codex to reach for the tools on the first try.