Cecil: skills for static sites and themes

Q: How do I install the Cecil skills in Claude Code?

Run gh skill install cecilapp/cecil with the GitHub CLI or npx skills add cecilapp/cecil. Both skills install, cecil and cecil-theme, and the agent loads the right one by the meaning of the task.

Cecil

Two skills for the PHP static site generator Cecil: the agent builds a site from Markdown and Twig, or packages a theme for Composer

299 ★ on the repository
Last commit Oct 29, 2026
EUPL-1.2

Skill

cecilapp/cecilAuthor:Cecilapp

Install

Works in: Claude Code
GitHub Copilot
Cursor
Koda
Coddy

In your terminal, with SkillFoxx CLI

npx skillfoxx add skills/cecil

Detects the agents on your machine, shows the access level and pins the version.

Other ways to install

Access and checks

How we review

Extended accessThe tool runs code or makes network calls and only reads external data.

The skill leads the agent to run builds, Composer commands and deployment
Adding ready component themes brings third-party code into the project

This is third-party code. Review the repository files before installing.

What it does

The Cecil repository ships two skills for agents. The cecil skill guides the agent through a whole site, from scaffolding and sections to build and deployment. It explains how Twig templates, assets and configuration work and helps find the cause of a failed build. It also knows the project layout, from Markdown pages in pages/ to your own PHP classes in extensions/. The cecil-theme skill helps create a theme: a full visual one or a small component theme that plugs into any site. It knows the conventions of the official Cecilapp/theme-* repositories, Composer packaging as cecil/theme-<name> and the order in which Cecil looks up layers, assets and translations. Before installing a ready component theme such as flexsearch or pwa, the agent has to ask you.

Who it is for. For developers who build Cecil sites and themes with a coding agent.

Good fit when

You need a Cecil blog with English and French versions without recalling the configuration syntax
The homepage needs a projects section with a card list built on Twig templates
The layouts of an existing site should become a theme that can be reused and published through Composer
A build fails or theme assets and settings are not picked up, and you need to find where a layer is overridden
You want to add a ready component theme such as search or PWA

Not a fit when

The site is built with another generator such as Hugo or Jekyll: the Cecil rules and directory layout do not apply
You need a dynamic site with a database and accounts: Cecil outputs static files
You only edit page text: the skill is unnecessary and a Markdown editor is enough
There is no PHP and Composer environment on the machine where the agent runs

Example request

Create a Cecil blog with English and French versions, add a projects section with cards on the homepage and show me how to build the site.

Limitations

PHP is needed for building, and Composer as well for themes and extensions. The skills are updated together with Cecil: reinstall them after upgrading the generator, otherwise the agent works from old instructions. The main skill is long, about 37,000 characters, and loads whole, so on a small edit it takes a noticeable share of the context. The content is tied to a specific Cecil version and its conventions, and for sites on an old version some advice may not fit. The skills are released under the EUPL-1.2 license, which sets conditions on distributing derived works.

How to disable. Delete the cecil and cecil-theme skill folders from the agent's skills directory, for example ~/.claude/skills/. Sites and themes you have already created stay in place.

FAQ

How do I install the Cecil skills in Claude Code?

Run `gh skill install cecilapp/cecil` with the GitHub CLI or `npx skills add cecilapp/cecil`. Both skills install, cecil and cecil-theme, and the agent loads the right one by the meaning of the task.

What does the cecil-theme skill do?

It creates visual and component themes and sets up options, translations and assets. It also packages a theme for Composer as cecil/theme-<name> and helps work out why layers or settings were not picked up.

Why reinstall the skills after upgrading Cecil?

The skills are updated together with the generator. Without a reinstall the agent relies on instructions from the old version.

Which agents are supported?

Claude Code, GitHub Copilot, Cursor and any other agent that supports the Agent Skills format.

What is in a Cecil project structure?

Settings live in cecil.yml, Markdown pages in pages/ and Twig templates in layouts/. Files to process go to assets/, files to copy as is to static/, data collections to data/ and your PHP classes to extensions/. The finished site is built into _site/.

Discussion

No questions or reviews yet.

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README in short

Cecil builds a site with a pipeline of steps, page generators and a Twig renderer, and pages are bound to folders in pages/. A nested folder with index.md becomes a sub-section with its own address. The docs/ai section covers the skills, the llms.txt file and rules for AI crawlers.

README badge

Original SKILL.md

---
name: cecil
description: Build and configure Cecil static sites, with focused guidance for content, templates, and site generation.
license: EUPL-1.2
---

# Cecil Site Builder

You are an expert Cecil developer capable of creating and generating static websites with Cecil, a PHP-based static site generator powered by Symfony components and Twig.

## When to Use This Skill

Use this skill when:

- Creating or scaffolding a new Cecil site
- Building and generating static websites with Cecil
- Configuring site settings, taxonomies, and content organization
- Creating or updating Twig templates and layouts
- Managing assets, including images and stylesheets
- Deploying Cecil-generated static sites
- Troubleshooting build issues or optimizing the performance of the generated site and build process
- Working with Cecil's plugin/extension system

## Project Structure

### Directory Layout

```
my-site/
├── cecil.yml  # Main configuration file (or config.yml)
├── pages/     # Markdown pages
├── layouts/   # Twig templates
├── assets/    # Processed files (CSS, JS, images)
├── static/    # Static files copied as-is
├── data/      # Data collections (YAML/JSON/...)
└── extensions/ # Custom PHP classes (generators, Twig extensions, post-processors)
```

### Key Directories

- **pages/** - Markdown content files organized into sections
- **layouts/** - Twig templates and partials
- **assets/** - Files handled by Cecil (Sass compilation, minification, image handling)
- **static/** - Files copied to output without transformation
- **data/** - Data files exposed in templates via `site.data`

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