Get expected value format for a field is a WordPress ability from Meta Box — usable via Easy MCP AI, which connects Claude, ChatGPT, and any AI assistant to your site.
Install Free Plugin →Get expected value format for a field
Read-onlyLook up the expected value format and a worked example for a Meta Box field type, or for one specific field.
Requires the Meta Box plugin on WordPress 6.9+ for the Abilities API (abilities are registered only when the wp_register_ability() function exists). The get, update, and delete abilities additionally require the target key to be a field Meta Box actually recognizes (verified via rwmb_get_field_settings) and the current user to hold the WordPress capability mapped from object_type: read_post/edit_post for posts, assign_term/edit_term for terms, read/edit_user for users, read/manage_options for settings pages, and read/moderate_comments for comments.
What it does
This ability tells you what shape of value a Meta Box field expects before you try to read or write it. Call it with just field_type (e.g. "checkbox_list", "background", "date") for generic type-level info, or with field_id plus object_id (and optionally object_type) to resolve the actual registered field and get precise info that accounts for its multiple and clone settings — since a field with multiple=true or clone=true wraps its value in an array, or a nested array of arrays when both are set. It's meant to be called before update-field-value so an AI assistant sends the value in exactly the shape Meta Box expects, instead of guessing and getting a silently-wrong save.
See it in action
You ask your AI assistant
"Before I update it, tell me what value format the 'gallery' field on post 128 expects — is it a single value or an array?"
Inputs
| Name | Type | Required | Description |
|---|---|---|---|
| field_type | string | No | Meta Box field type slug (e.g. "checkbox_list", "date", "background"). Alternative to field_id. |
| field_id | string | No | Field meta key. When given, resolves the field's real settings (multiple/clone) for a precise format. |
| object_id | integer|string | No | Object ID (post, term, user ID, or settings page slug). Required when field_id is given. |
| object_type | string | No | Object type: post, term, user, setting, or comment. Defaults to post. Used together with field_id. |
Returns
An object with the field_type, a human-readable format description, an example value, an is_array flag, an is_multiple flag, an is_cloneable flag (both false when only field_type is given), and a value_structure of scalar, array, or array_of_arrays describing the overall value shape.
Permission
When field_id and object_id are both given, the current user must hold the capability mapped from object_type for the update verb (e.g. edit_post for posts, edit_term for terms). When only field_type is given, any user with the base 'read' capability may call it.
More Meta Box abilities
Delete a custom field value
Permanently remove the stored value of a Meta Box custom field from an object.
Get a custom field value
Retrieve the stored value of a Meta Box custom field for a post, term, user, comment, or settings page.
Update (or create) a custom field value
Set the value of a Meta Box custom field, creating it if it doesn't already exist yet.