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wp-block-themes skill

/skills/wp-block-themes

This skill helps you develop WordPress block themes by managing theme.json, templates, patterns, and style variations across Site Editor workflows.

npx playbooks add skill automattic/agent-skills --skill wp-block-themes

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SKILL.md
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---
name: wp-block-themes
description: "Use when developing WordPress block themes: theme.json (global settings/styles), templates and template parts, patterns, style variations, and Site Editor troubleshooting (style hierarchy, overrides, caching)."
compatibility: "Targets WordPress 6.9+ (PHP 7.2.24+). Filesystem-based agent with bash + node. Some workflows require WP-CLI."
---

# WP Block Themes

## When to use

Use this skill for block theme work such as:

- editing `theme.json` (presets, settings, styles, per-block styles)
- adding or changing templates (`templates/*.html`) and template parts (`parts/*.html`)
- adding patterns (`patterns/*.php`) and controlling what appears in the inserter
- adding style variations (`styles/*.json`)
- debugging “styles not applying” / “editor doesn’t reflect theme.json”

## Inputs required

- Repo root and which theme is targeted (theme directory if multiple exist).
- Target WordPress version range (theme.json version and features vary by core version).
- Where the issue manifests: Site Editor, post editor, frontend, or all.

## Procedure

### 0) Triage and locate block theme roots

1. Run triage:
   - `node skills/wp-project-triage/scripts/detect_wp_project.mjs`
2. Detect theme roots + key folders:
   - `node skills/wp-block-themes/scripts/detect_block_themes.mjs`

If multiple themes exist, pick one and scope all changes to that theme root.

### 1) Create a new block theme (if needed)

If you are creating a new block theme from scratch (or converting a classic theme):

- Prefer starting from a known-good scaffold (or exporting from a WP environment) rather than guessing file layout.
- Be explicit about the minimum supported WordPress version because `theme.json` schema versions differ.

Read:
- `references/creating-new-block-theme.md`

After creating the theme root, re-run `detect_block_themes` and continue below.

### 2) Confirm theme type and override expectations

- Block theme indicators:
  - `theme.json` present
  - `templates/` and/or `parts/` present
- Remember the style hierarchy:
  - core defaults → theme.json → child theme → user customizations
  - user customizations can make theme.json edits appear “ignored”

Read:
- `references/debugging.md` (style hierarchy + fastest checks)

### 3) Make `theme.json` changes safely

Decide whether you are changing:

- **settings** (what the UI allows): presets, typography scale, colors, layout, spacing
- **styles** (how it looks by default): CSS-like rules for elements/blocks

Read:
- `references/theme-json.md`

### 4) Templates and template parts

- Templates live under `templates/` and are HTML.
- Template parts live under `parts/` and must not be nested in subdirectories.

Read:
- `references/templates-and-parts.md`

### 5) Patterns

Prefer filesystem patterns under `patterns/` when you want theme-owned patterns.

Read:
- `references/patterns.md`

### 6) Style variations

Style variations are JSON files under `styles/`. Note: once a user picks a style variation, that selection is stored in the DB, so changing the file may not “update what the user sees” automatically.

Read:
- `references/style-variations.md`

## Verification

- Site Editor reflects changes where expected (Styles UI, templates, patterns).
- Frontend renders with expected styles.
- If styles aren’t changing, confirm whether user customizations override theme defaults.
- Run the repo’s build/lint scripts if assets are involved (fonts, custom JS/CSS build).

## Failure modes / debugging

Start with:

- `references/debugging.md`

Common issues:

- wrong theme root (editing an inactive theme)
- user customizations override your defaults
- invalid `theme.json` shape/typos prevent application
- templates/parts in wrong folders (or nested parts)

## Escalation

If upstream behavior is unclear, consult canonical docs:

- Theme Handbook and Block Editor Handbook for `theme.json`, templates, patterns, and style variations.

Overview

This skill helps developers build, edit, and troubleshoot WordPress block themes focused on theme.json, templates, template parts, patterns, and style variations. It streamlines locating block theme roots, making safe theme.json changes, and resolving Site Editor/preview mismatches. The goal is predictable style hierarchy, correct template wiring, and reliable pattern and variation behavior.

How this skill works

The skill inspects the project to detect block theme roots and key folders, then guides edits to theme.json, templates/, parts/, patterns/, and styles/ with checks for WordPress version compatibility. It provides procedures to create or convert a block theme, confirms expected style inheritance, and includes verification steps to validate Site Editor and frontend behavior. It also lists common failure modes and debugging steps to quickly isolate issues.

When to use it

  • Editing theme.json presets, settings, or per-block styles
  • Adding or fixing templates (templates/*.html) and template parts (parts/*.html)
  • Creating or controlling theme-owned patterns (patterns/) and inserter visibility
  • Adding or updating style variations (styles/*.json)
  • Troubleshooting styles not applying in Site Editor, post editor, or frontend

Best practices

  • Start from a known-good scaffold or export rather than guessing theme layout
  • Be explicit about the minimum supported WordPress version for the theme.json schema
  • Treat settings (UI controls) separately from styles (visual defaults) when editing theme.json
  • Keep template parts directly in parts/ (do not nest) and templates in templates/
  • When changing style variations, remember user selections are stored in the database and may not auto-update

Example use cases

  • Convert a classic theme to a block theme and set a theme.json base typography and color scale
  • Fix a missing template part that breaks the Site Editor by ensuring correct parts/ placement
  • Add a theme-owned pattern to patterns/ and control its inserter visibility
  • Create a new style variation and verify the Styles UI and frontend render expected defaults
  • Debug a case where editor styles differ from frontend by checking theme.json shape, overrides, and active theme

FAQ

Why aren’t my theme.json changes visible in the Site Editor?

User customizations or a child theme can override theme.json defaults; also validate theme.json shape and that you edited the active theme root.

How do I choose the right theme.json schema version?

Base the schema on your minimum supported WordPress core version; different core versions enable different theme.json features and keys.