favicon

Generate a complete set of favicons from the source image at $1 and update the project's HTML with the appropriate link tags.

Prerequisites

First, verify ImageMagick v7+ is installed by running:

which magick

If not found, stop and instruct the user to install it:

macOS: brew install imagemagick
Linux: sudo apt install imagemagick

Step 1: Validate Source Image

Verify the source image exists at the provided path: $1
Check the file extension is a supported format (PNG, JPG, JPEG, SVG, WEBP, GIF)
If the file doesn't exist or isn't a valid image format, report the error and stop

Note whether the source is an SVG file - if so, it will also be copied as favicon.svg.

Step 2: Detect Project Type and Static Assets Directory

Detect the project type and determine where static assets should be placed. Check in this order:

Framework	Detection	Static Assets Directory
Rails	`config/routes.rb` exists	`public/`
Next.js	`next.config.*` exists	`public/`
Gatsby	`gatsby-config.*` exists	`static/`
SvelteKit	`svelte.config.*` exists	`static/`
Astro	`astro.config.*` exists	`public/`
Hugo	`hugo.toml` or `config.toml` with Hugo markers	`static/`
Jekyll	`_config.yml` with Jekyll markers	Root directory (same as `index.html`)
Vite	`vite.config.*` exists	`public/`
Create React App	`package.json` has `react-scripts` dependency	`public/`
Vue CLI	`vue.config.*` exists	`public/`
Angular	`angular.json` exists	`src/assets/`
Eleventy	`.eleventy.js` or `eleventy.config.*` exists	Check `_site` output or root
Static HTML	`index.html` in root	Same directory as `index.html`

Important: If existing favicon files are found (e.g., favicon.ico, apple-touch-icon.png), use their location as the target directory regardless of framework detection.

Report the detected project type and the static assets directory that will be used.

When in doubt, ask: If you are not 100% confident about where static assets should be placed (e.g., ambiguous project structure, multiple potential locations, unfamiliar framework), use AskUserQuestionTool to confirm the target directory before proceeding. It's better to ask than to put files in the wrong place.

Step 3: Determine App Name

Find the app name from these sources (in priority order):

Existing site.webmanifest - Check the detected static assets directory for an existing manifest and extract the name field
package.json - Extract the name field if it exists
Rails config/application.rb - Extract the module name (e.g., module MyApp → "MyApp")
Directory name - Use the current working directory name as fallback

Convert the name to title case if needed (e.g., "my-app" → "My App").

Step 4: Ensure Static Assets Directory Exists

Check if the detected static assets directory exists. If not, create it.

Step 5: Generate Favicon Files

Run these ImageMagick commands to generate all favicon files. Replace [STATIC_DIR] with the detected static assets directory from Step 2.

favicon.ico (multi-resolution: 16x16, 32x32, 48x48)

magick "$1" \
  \( -clone 0 -resize 16x16 \) \

favicon-96x96.png

apple-touch-icon.png (180x180)

web-app-manifest-192x192.png

web-app-manifest-512x512.png

favicon.svg (only if source is SVG)

If the source file has a .svg extension, copy it:

Step 6: Create/Update site.webmanifest

Create or update [STATIC_DIR]/site.webmanifest with this content (substitute the detected app name):

If site.webmanifest already exists in the static directory, preserve the existing theme_color, background_color, and display values while updating the name, short_name, and icons array.

Step 7: Update HTML/Layout Files

Based on the detected project type, update the appropriate file. Adjust the href paths based on where the static assets directory is relative to the web root:

If static files are in public/ or static/ and served from root → use /favicon.ico
If static files are in src/assets/ → use /assets/favicon.ico
If static files are in the same directory as HTML → use ./favicon.ico or just favicon.ico

For Rails Projects

Edit app/views/layouts/application.html.erb. Find the <head> section and add/replace favicon-related tags with:

Important:

If the source was NOT an SVG, omit the <link rel="icon" type="image/svg+xml" href="/favicon.svg" /> line
Remove any existing <link rel="icon", <link rel="shortcut icon", <link rel="apple-touch-icon", or <link rel="manifest" tags before adding the new ones
Place these tags near the top of the <head> section, after <meta charset> and <meta name="viewport"> if present

For Next.js Projects

Edit the detected layout file (app/layout.tsx or src/app/layout.tsx). Update or add the metadata export to include icons configuration:

Important:

If the source was NOT an SVG, omit the { url: '/favicon.svg', type: 'image/svg+xml' } entry from the icon array
If metadata export doesn't exist, create it with just the icons-related fields
If metadata export exists, merge the icons configuration with existing fields

For Static HTML Projects

Edit the detected index.html file. Add the same HTML as Rails within the <head> section.

If No Project Detected

Skip HTML updates and inform the user they need to manually add the following to their HTML <head>:

Step 8: Summary

Report completion with:

Detected project type and framework
Static assets directory used
List of files generated
App name used in manifest and HTML
Layout file updated (or note if manual update is needed)
Note if any existing files were overwritten

Error Handling

If ImageMagick is not installed, provide installation instructions and stop
If the source image doesn't exist, report the exact path that was tried and stop
If ImageMagick commands fail, report the specific error message
If the layout file cannot be found for HTML updates, generate files anyway and instruct on manual HTML addition

Framework

Detection

Static Assets Directory

Rails

config/routes.rb exists

public/

Next.js

next.config.* exists

public/

Gatsby

gatsby-config.* exists

static/

SvelteKit

svelte.config.* exists

static/

Astro

astro.config.* exists

public/

Hugo

hugo.toml or config.toml with Hugo markers

static/

Jekyll

_config.yml with Jekyll markers

Root directory (same as index.html)

Vite

vite.config.* exists

public/

Create React App

package.json has react-scripts dependency

public/

Vue CLI

vue.config.* exists

public/

Angular

angular.json exists

src/assets/

Eleventy

.eleventy.js or eleventy.config.* exists

Check _site output or root

Static HTML

index.html in root

Same directory as index.html

Documentation

Documentation

Prerequisites

Step 1: Validate Source Image

Step 2: Detect Project Type and Static Assets Directory

Step 3: Determine App Name

Step 4: Ensure Static Assets Directory Exists

Step 5: Generate Favicon Files

favicon.ico (multi-resolution: 16x16, 32x32, 48x48)

favicon-96x96.png

apple-touch-icon.png (180x180)

web-app-manifest-192x192.png

web-app-manifest-512x512.png

favicon.svg (only if source is SVG)

Step 6: Create/Update site.webmanifest

Step 7: Update HTML/Layout Files

For Rails Projects

For Next.js Projects

For Static HTML Projects

If No Project Detected

Step 8: Summary

Error Handling

Documentation

favicon

Documentation

Prerequisites

Step 1: Validate Source Image

Step 2: Detect Project Type and Static Assets Directory

Step 3: Determine App Name

Step 4: Ensure Static Assets Directory Exists

Step 5: Generate Favicon Files

favicon.ico (multi-resolution: 16x16, 32x32, 48x48)

favicon-96x96.png

apple-touch-icon.png (180x180)

web-app-manifest-192x192.png

web-app-manifest-512x512.png

favicon.svg (only if source is SVG)

Step 6: Create/Update site.webmanifest

Step 7: Update HTML/Layout Files

For Rails Projects

For Next.js Projects

For Static HTML Projects

If No Project Detected

Step 8: Summary

Error Handling