xero-oauth-mcp-server

A custom Model Context Protocol server for Xero, using the standard OAuth2 authorization-code + refresh-token flow (no paid Custom Connection required). Supports multiple connected organisations (tenants) — every tool takes an optional org argument.

Capabilities

• Contacts: list_contacts, get_contact, create_contact, update_contact

• Invoices: list_invoices, get_invoice, create_invoice, update_invoice, list_overdue_invoices, list_recurring_invoices

• Utility: list_organisations, list_accounts

Related MCP server: Xero Expenses MCP

How org selection works

Each tool accepts an optional org. It is resolved (case-insensitive) against:

1. an alias from XERO_ORG_ALIASES (e.g. main → a tenantId),

2. an exact tenantId, then

3. a substring of the org's name in Xero.

If org is omitted, the server uses XERO_DEFAULT_ORG (which may itself be an alias), or the first connected org when that is unset.

One-time setup

1. Create a Xero app

developer.xero.com → New app → Web app.

• Add redirect URI: http://localhost:49831/callback

• Copy the Client ID and generate a Client Secret.

Newer Xero apps use granular scopes. This server requests accounting.contacts, accounting.invoices, and accounting.settings.read (plus openid profile email offline_access). Make sure those are enabled on the app.

2. Build

npm install
npm run build

3. Authorize (interactive, once)

XERO_CLIENT_ID=xxx XERO_CLIENT_SECRET=yyy npm run auth

A browser opens — log in and authorize each organisation you want to use (re-run to add more later). The refresh token and the connected tenant list are saved to ~/.xero-mcp-id/tokens.json (chmod 600). The refresh token rotates automatically on every use.

4. Register with an MCP client

Example (Claude Code):

claude mcp add xero -s user \
  -e XERO_CLIENT_ID=xxx \
  -e XERO_CLIENT_SECRET=yyy \
  -e XERO_DEFAULT_ORG=main \
  -e XERO_ORG_ALIASES='{"main":"<tenant-guid>","secondary":"<tenant-guid>"}' \
  -- node /absolute/path/to/dist/index.js

Environment variables

Security

• No credentials or tokens are stored in this repository.

• Client ID/secret are passed via environment; the refresh token + tenant list live only in XERO_TOKEN_DIR (default ~/.xero-mcp-id/, chmod 600), which is git-ignored.

• Write tools (create_* / update_*) can be globally disabled with XERO_READONLY=true.

License

MIT