# add_auth_descriptor · FT4 Rell API · Chromia Docs (concept)

> function add_ auth_ descriptor(account: account , auth_ descriptor: auth_descriptor ): account_ auth_ descriptor Adds an auth descriptor to an account. Can

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.accounts/add_auth_descriptor/

FUNCTION

# add\_auth\_descriptor

```signature
function add_auth_descriptor(account: account, auth_descriptor: auth_descriptor): account_auth_descriptor
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/module.rell#lines-232)

Adds an auth descriptor to an account.

Can only be called from an operation.

Throws `"TOO MANY AUTH DESCRIPTORS"` if the account already has
`AUTH_DESCRIPTORS_PER_ACCOUNT_UPPER_BOUND` number of auth descriptors registered to it.

Throws if `auth_descriptor`'s `args` field is invalid. Common cases include:

* if a multi-sig auth descriptor's `required_signatures` is 0 or less
* if a multi-sig auth descriptor's `required_signature` parameter is greater than the number
  of signers

Throws if `auth_descriptor`'s `rules` field is invalid. Common cases include:

* `rules` is a complex rule with too many rule components
* `rules` has already expired
* `rules` is not the valid GTV representation of a rule

**Parameters**

* **account** — the account to add the auth descriptor to
* **auth\_descriptor** — the auth descriptor to add

**Returns**

The newly created `account_auth_descriptor` entity

**See Also**

* [account\_auth\_descriptor.rules](https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.accounts/account_auth_descriptor/) — for the list of valid GTV representations of rules

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.accounts/add_auth_descriptor.html)Generated API reference, mirrored from the live docs