github-wiki

name	github-wiki
description	This skill should be used when creating, editing, or managing GitHub wiki pages. Use when writing wiki content, creating internal links between wiki pages, adding images, updating sidebar navigation, or working with .wiki.git repositories. Triggers on "wiki", "wiki page", "update the wiki", "add to wiki", or when working in a *.wiki directory or *.wiki.git repository.

GitHub Wiki

Overview

GitHub wikis are powered by Gollum, a git-backed wiki engine. Wiki content lives in a separate .wiki.git repository alongside the main code repository. Understanding Gollum's link syntax and page resolution is essential — it differs from both standard Markdown and MediaWiki in ways that cause subtle, hard-to-debug broken links.

Critical: Link Syntax

The most common mistake when working with GitHub wikis is getting the pipe syntax backwards. Gollum uses the opposite order from MediaWiki:

CORRECT:  [[Display Text|page-name]]
WRONG:    [[page-name|Display Text]]

• Left of pipe = what the reader sees
• Right of pipe = the page to link to (filename without .md)

When the order is reversed, links silently resolve to non-existent pages and render as red/broken links with no error message.

For the full link syntax reference including resolution rules, image handling, and special pages, read references/gollum-link-syntax.md.

Working with Wiki Repositories

Locating the Wiki Repo

Wiki repositories are cloned separately from the main repo:

git clone https://github.com/OWNER/REPO.wiki.git

Within a project, the wiki repo is typically at a path like code/REPO.wiki/ or similar. Check the project's CLAUDE.md or memory files for the exact location.

Pushing Changes

Wiki changes are pushed with standard git commands. Changes appear on GitHub immediately after push — there is no build step or CI.

cd path/to/repo.wiki
git add -A
git commit -m "Description of changes"
git push origin master

Note: Wiki repos typically use master as the default branch, not main.

Creating Wiki Pages

Page Files

Each wiki page is a Markdown file at the root of the wiki repository.

• Filename = URL slug and link target (e.g., my-page.md → /wiki/my-page)
• H1 heading = Page title displayed at the top
• Use kebab-case for filenames: setup-guide.md, not Setup Guide.md
• Capitalize proper nouns: Banner.md, Home.md

Naming for Grouping

Prefix related pages to keep them organized:

its-training-session-1-pantheon.md
its-training-session-2-git.md
its-training-session-3-drupal.md

Internal Links

Always use wiki-style [[links]] for internal pages:

See [[Setup Guide|setup-guide]] for details.

Never use markdown-style [text](page) for internal wiki links — they will not resolve.

Cross-Page Navigation

Add prev/next navigation at the bottom of sequential pages:

**Previous:** [[Session 1|training-session-1]] | **Next:** [[Session 3|training-session-3]]

Special Pages

File	Purpose
Home.md	Landing page, always exists
_Sidebar.md	Navigation sidebar, rendered on every page
_Footer.md	Footer rendered on every page (optional)
_Header.md	Header rendered on every page (optional, rare)

Sidebar Best Practices

Keep the sidebar organized with sections and wiki-style links:

# Project Wiki

[[Home]]

---

### Section Name

- [[Page One|page-one]]
- [[Page Two|page-two]]

---

### External Links

- [GitHub Issues](https://github.com/OWNER/REPO/issues)

Images

Store images in an images/ directory at the wiki repo root. Reference with standard markdown or wiki syntax:

![Alt text](images/screenshot.png)

GitHub wiki does not support image sizing in markdown. Use HTML for controlled dimensions:

<img src="images/screenshot.png" alt="Alt text" width="600">

Workflow: Adding a New Wiki Section

1. Create the page files at the wiki repo root with kebab-case names
2. Add internal links using [[Display Text|page-name]] syntax
3. Update _Sidebar.md to add navigation links to the new pages
4. Update Home.md if the new section should be listed on the landing page
5. Commit and push to make changes live immediately
6. Verify links — broken links render as red text with class internal absent

Troubleshooting

Links Show as Red / "absent"

• Check pipe order: must be [[Display|target]] not [[target|Display]]
• Verify the target filename exists (without .md extension) at repo root
• Check for typos — resolution is case-insensitive but must otherwise match

Images Not Rendering

• Verify the image file is committed and pushed to the wiki repo
• Check the relative path from the wiki root (e.g., images/file.png)
• Ensure the image filename has no spaces

Page Not Appearing in Wiki

• Verify the .md file is at the repository root (not in a subdirectory unless using Gollum subdirectory support)
• Verify the file was pushed to the remote (git push origin master)
• Check that the file has a .md extension