About this plugin
Pattern Builder puts a theme’s pattern files and the patterns saved in the editor on one screen under Appearance, opens either kind in the WordPress editor, and writes theme patterns back to the theme’s files. Nothing is mirrored into the database, so the theme in your repository is the theme on the site.
It also gives an AI agent a proper set of tools for the same work. Connect Claude from the Agents tab and it can read the site’s design system, write patterns that use it, check them before they’re saved, and read and write the theme’s templates and template parts. Every operation is a tool of its own, so you can let it read freely and approve each change it makes.
Working with an agent
Connecting is one paste. The Agents tab checks what a connection needs, installs the MCP Adapter plugin for you when it’s missing, creates a password only the agent uses, and hands you a message for Claude Code. Paste it in and Claude sets the connection up itself.
Each connection is listed with when it was last used, and any of them can be revoked in one click.
What the agent can do. List, read, render, create and update patterns. Read the design system and add to it: color, spacing and type presets, global styles, block style variations and the layout widths.
Find the images the site already has, and add images and fonts. Read, create, change and delete the theme’s templates and template parts. com and install from it through your account, without ever holding a cloud credential.
What the writes refuse. A write that fails Pattern Builder’s checks is refused with the problem named, and the authoring guide has the agent run the block validator, against the WordPress your site runs, before it saves anything. A theme pattern file can’t be made to carry PHP, so permission to edit patterns is never permission to run code on the site.
The skills that travel with it. pattern-author is how a pattern gets written: the theme’s own design tokens, markup that checks as valid, and sections factored out so a layout is built once and placed many times. design-reproduction is for rebuilding a design that already exists, whether a live site, a screenshot or a Figma file.
Claude installs either one from your site with a single command.
No model inside. Pattern Builder has no AI in it and sends nothing to any AI service. The tools are WordPress core’s Abilities API, served over REST and, through the MCP Adapter plugin, as MCP tools, so any MCP client can connect; the Agents tab writes the message for Claude Code.
9 or later. 8.
Editing patterns yourself
Theme and user patterns on one screen. Theme patterns (the PHP files in your theme’s patterns folder, parent theme included) and user patterns (the ones saved in the editor) are browsed together, with the same previews, search and categories, and each opens in the WordPress editor. A theme pattern is written back to its file with everything in its header: title, description, categories, keywords, block types, post types, template types, viewport width, inserter visibility and synced status.
Synced theme patterns. A synced pattern kept in a file is placed through the core pattern block, so inserted copies stay linked to the file and each copy can override the content you’ve opened up for editing. Design stays locked to the theme.
Content stays editable.
Pattern Bindings. Bind a block’s value to a post type’s custom fields, to Advanced Custom Fields, or to any registered binding source, picked per attribute from the fields that post type really offers. Or leave a slot for whoever places the pattern to fill in.
The patterns your plugins register. The Plugin tab browses them beside your own. A plugin owns those, so they’re read-only until you copy one into the theme, which brings its images and every pattern it’s built from, and from then on it’s yours to edit.
Shipping the theme. A production site that only needs to render synced theme patterns can run Synced Patterns for Themes, the free runtime, instead of this plugin. When the theme is updated, only the theme’s changes arrive, and the site uses the patterns without being able to change them.
Your patterns on other sites
Everything above works without an account. com from Appearance > Pattern Builder. A free account keeps up to 25 patterns in a private Personal collection and installs them on any number of connected sites.
The Directory tab browses the collections Twenty Bellows and partner studios publish; save one pattern or a whole collection to a site, with the design tokens it needs, as theme patterns or user patterns, images included. A page pattern travels with the patterns it references.
Pro is a subscription on your account, $9 a month or $89 a year, not a license for the plugin. It removes the cap, adds private collections of your own, and opens the premium collections. Cancel, and what you’ve uploaded stays readable and installable.
External services
Everything local works without an account and without sending anything anywhere. The services below are involved only when you choose to use them.
com: the cloud library and its directory of curated collections, and the account behind them. com; only the returned access token is stored, on this site, for your WordPress user. com through this site.
com: the website shows collections and sends people here. Anonymous usage reporting, if you allow it, goes there too (see below). com/privacy/
Freemius: the checkout for Pattern Builder Pro. com/js/v1/) on the Pattern Builder screen and opens their checkout; nothing from Freemius loads anywhere else or before that click. com/privacy/
org: installing a font. com/). The files are saved to your site and served from it, so your visitors’ browsers never request anything from Google.
No request is made until you install a font. com/privacy
Usage reporting (opt-in)
The first time the pattern browser opens on a site, it asks once whether Pattern Builder may report anonymous usage, with Allow and No thanks buttons. Nothing is sent unless an administrator chooses Allow, and the choice can be changed on the same screen at any time.
What is sent when allowed: which features are used (the browser opened, a pattern created, the community browsed, an upload or download) and the environment (WordPress, PHP and plugin versions, locale, active theme, multisite, and environment type), under a random install id. What is never sent: the site’s address or name, pattern content, or anything about the site’s visitors.
Development
Pattern Builder is developed in the open by Twenty Bellows. Report a bug or send a change at the GitHub repository.