building-themes

building-themes is a skill for Claude Code, Codex from MacareuxDigital/concretecms-skills. It costs 47 tokens per session (1,625 once invoked), scanned A, original, MIT.

Guidance for building custom themes in Concrete CMS, including page layouts, shared headers and footers, and website assets. It also covers newer Concrete CMS features such as reusable content containers.

In plain words
What is it for?
Use it when creating or modifying a Concrete CMS theme, page templates, asset loading, grids, or containers.
Why use it?
It gives the expected files and folder locations, so a theme fits Concrete CMS's structure and can be maintained consistently.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when creating or modifying a Concrete CMS theme, page templates, asset loading, grids, or containers.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/macareuxdigital/concretecms-skills/building-themes
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add MacareuxDigital/concretecms-skills --skill building-themes
Clone the repo
git clone --depth 1 https://github.com/MacareuxDigital/concretecms-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for building-themes

README.md
[![agentmods](https://agentmods.dev/badge/skills/macareuxdigital/concretecms-skills/building-themes/github.svg)](https://agentmods.dev/skills/macareuxdigital/concretecms-skills/building-themes)
Your own site
<a href="https://agentmods.dev/skills/macareuxdigital/concretecms-skills/building-themes"><img src="https://agentmods.dev/badge/skills/macareuxdigital/concretecms-skills/building-themes/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for building-themes

Your own site · 80×15
<a href="https://agentmods.dev/skills/macareuxdigital/concretecms-skills/building-themes"><img src="https://agentmods.dev/badge/skills/macareuxdigital/concretecms-skills/building-themes.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,625 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00047 $0.01625
Opus 5 $0.00023 $0.00813
Sonnet 5 $0.00009 $0.00325
Haiku 4.5 $0.00005 $0.00162

Measured 12d ago against content hash c92229e538bf, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

building-themes scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

building-themes/SKILL.md · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building Themes

Overview

This skill enables the development of professional, feature-rich themes for Concrete CMS. It covers the essential components like page_theme.php, page templates, asset registration, and advanced features such as grid support and containers.

For the most up-to-date best practices and implementation examples, refer to the concrete/themes/atomik directory in the core. It serves as the primary reference for modern theme development in Concrete CMS.

Workflow

1. Setup Theme Directory

Themes should be placed within a package for better portability. Otherwise, they can be stored in the application directory.

  • Path: packages/your_package_handle/themes/your_theme_handle/
  • Path: application/themes/your_theme_handle/

2. Create Core Files

Every theme requires at least:

  • page_theme.php: The main configuration class for the theme.
  • default.php: The default page template.
  • view.php: Required for single pages. Should include the system_errors element and $innerContent.
  • elements/header.php & elements/footer.php: Shared header and footer.
  • Recommended: Sub-divide elements for simplicity (e.g., elements/header_top.php, elements/header.php, elements/footer.php, elements/footer_bottom.php).

3. Configure page_theme.php

  • Define namespace: Concrete\Package\YourPackageHandle\Theme\YourThemeHandle
  • Required Methods:
    • getThemeName(): Return the localized name of the theme.
    • getThemeDescription(): Return the localized description of the theme.
  • Implement getThemeSupportedFeatures() to optimize asset loading.
    • JS Library Themes: If the theme includes a full-featured JavaScript library (e.g., Bootstrap 5 JS, jQuery), list all supported features (e.g., FeatureConstants::NAVIGATION, FeatureConstants::FORMS) to avoid conflicts with Concrete's internal asset loading.
    • No-JS Themes: If the theme does not include any JavaScript, it is recommended not to implement this method.
  • Configure grid support via $pThemeGridFrameworkHandle.
    • Core Frameworks: If using a supported framework (e.g., bootstrap5, bootstrap4), set this property to the corresponding handle.
    • Custom Frameworks: If the theme uses a custom or unsupported CSS framework (e.g., Tailwind, Bulma), do not set this property.
    • Supported Handles: Find available frameworks in concrete/src/Page/Theme/GridFramework/Type (e.g., bootstrap5, foundation, nine_sixty).

Read the full file on GitHub · 87 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 87 lines · 47 tokens per session scan A c92229e538bf

Subscribe to this mod's changes

building-themes is a skill published in the GitHub repository MacareuxDigital/concretecms-skills (9 stars, last pushed 3mo ago), licensed MIT. It adds 47 tokens to every session and 1,625 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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