Ensure the Item was created with 'auth' in the products list at /link/token/create time; calling /auth/get on an Item without auth enabled returns a PRODUCT_NOT_READY or PRODUCTS_NOT_SUPPORTED error
POST to /auth/get with client_id, secret, and access_token; optionally include options.account_ids to fetch only specific accounts
The response contains an accounts array and a numbers object; the numbers object has sub-objects for each routing number format: ach (routing + account), eft (for Canadian items), international, and bacs
For US ACH use cases, read numbers.ach[].routing and numbers.ach[].account for the account's ABA routing number and full account number
Match each entry in numbers.ach to the corresponding account via the account_id field present in both the accounts array and the numbers.ach entries
Use the retrieved routing and account numbers to originate ACH debits or credits through your bank or ACH processor
Known gotchas
Some institutions support only instant auth while others return account numbers only after microdeposit verification; the same_day_microdeposits or microdeposit_verification flow in Link handles the latter case
The numbers object may be empty for accounts that do not support ACH; always check for the presence of the ach array before using its values
Do not cache routing and account numbers for longer than necessary; if the user re-links or the item resets, the account number could change
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp