mailerpress/list-free-custom-fields lists every contact custom-field definition on the site.
It dispatches to the free plugin’s endpoint, which exists on all MailerPress installs.
At a glance
| Ability | mailerpress/list-free-custom-fields |
| Toolset | MailerPress — toolset/mailerpress |
| Group | MailerPress › Contacts |
| Requires | AcrossAI Pro, plus MailerPress active on the site |
| Capability | manage_options |
| Safety | Read-only — changes nothing |
| Repeatable | Idempotent — running it twice leaves the same result |
| Ships in | AcrossAI Pro 0.9.16 and later |
How it works
MailerPress has two custom-field surfaces. The free plugin exposes a singular /custom-field route; MailerPress Pro exposes a plural /custom-fields one, with its own abilities.
The distinction matters because an agent on a site without Pro that reaches for the Pro ability gets a failure, and concludes the site has no custom fields rather than that it has no Pro.
So this exists as the universally available read — the one to use when you do not know whether Pro is installed.
The field keys returned here are what mailerpress/create-contact and mailerpress/update-contact write under, and what campaign personalisation tokens reference.
A campaign token for a field that does not exist renders as nothing, silently — so checking the keys before writing a campaign is the same check as before writing a contact.
Input
This ability takes no input.
What comes back
| Name | Type | What it is |
|---|---|---|
fields | array | Each definition with its key, label and type. |
success | boolean | Whether the call completed. |
message | string | A one-line summary of what happened, suitable for showing a human. |
error_code | string | Present only on failure — a stable machine-readable reason, such as a missing field, a wrong field type or an unmet confirmation. |
Example
Ask your assistant:
What custom fields do contacts have?
It resolves to one call:
{
"ability": "mailerpress/list-free-custom-fields",
"parameters": {}
}Worth knowing
- Available on every install, unlike the Pro equivalent.
- A Pro-only call failing is easily misread as “no custom fields”.
- These keys are what campaigns and contact writes both reference.
- A token for a missing field renders as nothing.
Related abilities
- MailerPress Create Custom Field (Free) — add one
- MailerPress Pro List Custom Fields — the Pro surface
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