ACF MCP — Update Advanced Custom Fields with AI (9 Tools)

What is ACF MCP?

ACF MCP means reading and updating your Advanced Custom Fields data by asking an AI assistant instead of editing each post by hand. Cowboy MCP's ACF integration gives an AI agent 9 tools over the Model Context Protocol whenever Advanced Custom Fields is active, so your assistant can audit which field groups exist, read and write field values across posts, users, terms, and options, and maintain repeater rows — every write previewed and reversible.

MCP is the open standard an AI client uses to discover and call those tools, and the same Cowboy MCP plugin that manages your posts and users surfaces the ACF tools automatically whenever Advanced Custom Fields is active. The agent works with the field values and the group structure that already exist: it reads your schema to learn field names and types, then reads or writes the values you point it at.

What can an AI agent do with ACF?

An agent can do the field work that is tedious to do post by post: discover which field groups exist and what fields they contain, read a single field or every field on an object, create or update a field value, delete a value, and add, update, or delete repeater and flexible-content rows. Each of the 9 tools maps to one real ACF operation, and it works on posts, users, terms, and options pages.

The tools group into three areas. The names below are the real tool identifiers the agent sees.

Schema discovery

Tool	What it does
wp_acf_get_field_groups	List all field groups with their location rules, status, and position
wp_acf_get_field_group_fields	List every field in a group, expanding repeater, group, and flexible-content sub-fields

Field values

Tool	What it does
wp_acf_get_field	Read one field's value for a post, user, term, or options page
wp_acf_get_fields	Read every ACF field value on an object at once
wp_acf_update_field	Create or update a field's value
wp_acf_delete_field	Delete a field's value from an object

Repeater and flexible-content rows

Tool	What it does
wp_acf_add_row	Append a row to a repeater or flexible-content field
wp_acf_update_row	Update an existing row by its 1-based row number
wp_acf_delete_row	Delete a row from a repeater or flexible-content field

Three real prompts, to make it concrete:

• "List all my ACF field groups and tell me which are inactive and which post types each one is attached to."
• "Set the 'featured_product' true/false field to true on posts 88, 91, and 104 — show me a dry run first."
• "On the About page, add a row to the 'team_members' repeater for 'Dana Lee, CTO', then update row two's title to 'Head of Design'."

How do field writes stay safe?

Bulk-editing custom fields across many posts is only safe if you can preview and reverse it. Cowboy MCP wraps every ACF write in the same guardrails it uses across the whole site: a dry-run preview, a confirmation gate on the two destructive tools, a per-change undo entry, and a full audit trail.

• Dry run — every write tool, from wp_acf_update_field to wp_acf_add_row, can report exactly what it would change without saving, so you preview a bulk field update before it runs.
• Safe mode — the two destructive tools, wp_acf_delete_field and wp_acf_delete_row, will not run until you confirm; it is on by default. Updating a value or adding a row is a write but is not flagged destructive, so it runs without a prompt — while still being previewable and reversible.
• Undo journal — every ACF write, whether it updates a field, deletes one, or adds, updates, or deletes a repeater row, is captured as its own entry, so a wrong edit rolls back from the Activity tab without disturbing anything else.

Every call is also written to the audit log, and your MCP client asks you to approve each tool call, so a human stays in the loop at both layers. The full guardrail model lives on the security page.

What are ACF MCP's limits?

Cowboy MCP works with your ACF field values and structure, not with the field definitions themselves. It reads your field groups and the fields inside them, and it reads and writes the values stored against posts, users, terms, and options — but it does not create field groups or define new custom fields. Building a new field group, adding a field, or changing a field's type still happens in the ACF interface or in your code.

That split matters. The agent is built for value work at scale — auditing where a field group is used, filling a field across dozens of posts, or tidying repeater rows — because those are data operations against fields that already exist. It reads the schema, through wp_acf_get_field_groups and wp_acf_get_field_group_fields, so it knows the field names and types to target, but the schema itself is read-only to the agent. It also inherits ACF's own behavior: values are read and written through ACF's own functions, so results match what you would see in the editor, and the repeater and flexible-content tools work with whatever fields of those types your ACF setup provides.

How do I set it up?

Setup takes about five minutes and needs no code. Install the Cowboy MCP plugin, make sure Advanced Custom Fields is active so the tools register, then connect your AI assistant and start with a read-only request like listing your field groups. The ACF tools appear automatically once both plugins are running — there is nothing extra to switch on.

1. Install the plugin. In wp-admin, go to Plugins → Add New, search for "Cowboy MCP", and click Install then Activate. It is free on the WordPress.org plugin directory (opens in new tab) and needs WordPress 6.2+ and PHP 8.0+.
2. Connect your AI. Open Settings → Cowboy MCP and follow the guided setup. See how to connect WordPress to Claude or how to connect WordPress to ChatGPT for the full walkthrough.
3. Ask for something real. Start read-only — "list all my ACF field groups and where each one is used" — then let it act. Safe mode checks with you before it deletes a field value or a row.

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