# E12008 — SMSTemplateVariableUnexpected

parameters contains a variable the template does not define.

- **HTTP status**: `422`
- **Type**: `validation_error`
- **Name**: `SMSTemplateVariableUnexpected`

## What to do

parameters includes a variable this template does not define. Fetch the template to see the variable keys it accepts, then drop the extra ones from parameters and resend.

Operations that resolve this:

- [Get an SMS template](/docs/api/reference/get-sms-template)

## Related

- [E12xxx — SMS sending & delivery](/docs/api/errors/E12xxx): every code in this range
- [Errors](/docs/api/errors): the full wire contract, status mapping, and error catalog
- [Error handling](/docs/guides/errors): branching on `type` and `code`, validation details, and `vendor_code`