GEO-First SEO Audit Tool
zubair-trabzada/geo-seo-claude
Audits a website for AI search visibility across ChatGPT, Claude, Perplexity and Google AI Overviews while checking traditional SEO, schema and E-E-A-T content quality.
A skill your agent uses when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers.
Install Canonical Header
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install thedaviddias/Front-End-Checklist canonical-header --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/canonical-header .claude/skills/canonical-header && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .claude/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-headerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install thedaviddias/Front-End-Checklist canonical-header --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/canonical-header .agents/skills/canonical-header && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .agents/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install thedaviddias/Front-End-Checklist canonical-header --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/canonical-header .cursor/skills/canonical-header && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .cursor/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/thedaviddias/Front-End-Checklist.git --path skills/canonical-header--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install thedaviddias/Front-End-Checklist canonical-header --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/canonical-header .gemini/skills/canonical-header && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .gemini/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install thedaviddias/Front-End-Checklist canonical-headerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/canonical-header .github/skills/canonical-header && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .github/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install thedaviddias/Front-End-Checklist canonical-header --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/canonical-header .opencode/skills/canonical-header && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "canonical-header" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/canonical-header into .opencode/skills/canonical-header/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-header", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
canonical-header- GitHub stars
- 74k
- Token cost
- ~432 tokens
- SKILL.md length
- 176 words
- Files
- 2 (incl. references)
- Skills in repo
- 390
- Repo updated
- First seen
- Licence
- MIT
At a glance
A skill your agent uses when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers.
- Auditing metadata
- SKILL.md covers Quick Reference, Check, Fix and Explain, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Structured data
What it does
Canonical Header is an agent skill from thedaviddias/Front-End-Checklist. Use when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers. Verify the rendered HTML and HTTP response rather than relying only on source files.
Its SKILL.md is about 430 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/rule.md`).
It sits in Marketing & SEO, covering Technical SEO and Schema markup. The repository describes itself as: 🗂 The essential checklist for modern web development, for humans and AI agents. The licence is MIT.
When your agent uses it
- Auditing metadata
- Structured data
- Indexability related to Sync HTML canonical tags and Link headers
Example prompts
- “/canonical-header”
What it can do on your machine
Read from SKILL.md and the folder at commit e8d14d0. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
frontendchecklist.io
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Canonical Header loads about 432 tokens when it runs, and up to ~1.1k if it reads all its reference files. Until then it costs about 58 tokens; SKILL.md has 176 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from thedaviddias/Front-End-Checklist at commit e8d14d0, republished under its MIT licence (© thedaviddias). 176 words, ~432 tokens.
Download SKILL.mdSave it as
.claude/skills/canonical-header/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- canonical-header
- description
- Use when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers. Verify the rendered HTML and HTTP response rather than relying only on source files.
- metadata.category
- seo
- metadata.priority
- medium
- metadata.difficulty
- intermediate
- metadata.estimatedTime
- 10
- metadata.source
- frontendchecklist.io
- metadata.url
- https://frontendchecklist.io/rules/seo/canonical-header
Sync HTML canonical tags and Link headers
Conflicting canonical-url signals can lead search engines to ignore both declarations, potentially causing duplicate content issues and incorrect indexing.
Quick Reference
- Ensure the
rel="canonical"tag in your HTML matches theLinkcanonical-url header if both are used - Avoid sending conflicting signals to search engines about the primary version of a page
- Maintain consistency across all methods of declaring your canonical URL
Check
Compare the HTML canonical tag with the HTTP Link header to ensure they point to the exact same URL.
Fix
Update either the HTML tag or the HTTP header so that they provide a consistent canonical URL signal.
Explain
Explain the risks of sending conflicting technical SEO signals to search engine crawlers.
Code Review
Review metadata generation, rendered HTML, structured data, and response headers related to Sync HTML canonical tags and Link headers. Flag exact routes or templates where search-facing output violates the rule, and describe how to verify the final page output.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/seo/canonical-header
© thedaviddias, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in skills/canonical-header of thedaviddias/Front-End-Checklist.
- SKILL.md
- references/rule.md
Open the folder on GitHubat commit e8d14d0
Compare with similar skills
Canonical Header next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Canonical Header this skillthedaviddias/Front-End-Checklist | 74k | — | ~432 | Automated safety check: Pass | MIT | |
| GEO-First SEO Audit Toolzubair-trabzada/geo-seo-claude | 11k | — | ~2.8k | Automated safety check: Notes | MIT | |
| SEO Optimizerailabs-393/ai-labs-claude-skills | 455 | 1 repos | ~3.2k | Automated safety check: Pass | MIT | |
| SEO and GEO Auditdageno-agents/seo-geo-audit | 176 | — | ~2k | Automated safety check: Pass | MIT | |
| SEO Setupalisamadiii/Portfolio | 180 | — | ~1.7k | Automated safety check: Pass | None | |
| SEOever-works/ever-works | 162 | 10 repos | ~2.9k | Automated safety check: Pass | MIT |
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ailabs-393/ai-labs-claude-skills
This skill should be used when analyzing HTML/CSS websites for SEO optimization, fixing SEO issues, generating SEO reports, or implementing SEO best practices.
SEO and GEO Audit
dageno-agents/seo-geo-audit
Runs one prioritized audit that combines technical SEO, content quality, trust signals, entity clarity and AI search readiness for a page, site or domain.
SEO Setup
alisamadiii/Portfolio
Full SEO/metadata setup and audit for client websites (Astro, Next.js, any static site).
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Optimize for search engine visibility and ranking. An agent skill from ever-works/ever-works.
Universal SEO Analysis
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Hub for site-wide SEO work: audits, technical checks, schema, content quality, local, hreflang and AI-search readiness, run through slash commands.
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Checks that a site's favicon is linked, reachable and large enough for Google search results, and sets up ICO, SVG and Apple touch icon files when they are missing.
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Audits article pages for freshness signals, covering the Last-Modified header, Article JSON-LD dateModified and a visible last-updated date, and fixes mismatches.
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Scores and rewrites a Front-End Checklist rule MDX file against a scored quality rubric, replacing generic stub prompts with specific, actionable ones.
Related
Categories
Questions about Canonical Header
What does Canonical Header do?
A skill your agent uses when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers. Canonical Header is an agent skill from thedaviddias/Front-End-Checklist. Use when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers.
When should I use Canonical Header?
Canonical Header fits situations like: auditing metadata; structured data; indexability related to Sync HTML canonical tags and Link headers.
How do I install Canonical Header in Claude Code?
Run `npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a claude-code`. Or copy the skill folder (skills/canonical-header in thedaviddias/Front-End-Checklist) into .claude/skills/canonical-header in your project. Claude Code loads it when a task matches its description.
How do I install Canonical Header in Codex?
Run `npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a codex`. Or copy the skill folder (skills/canonical-header in thedaviddias/Front-End-Checklist) into .agents/skills/canonical-header in your project. Codex loads it when a task matches its description.
Can I use Canonical Header in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add thedaviddias/Front-End-Checklist --skill canonical-header -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/canonical-header, .gemini/skills/canonical-header, .github/skills/canonical-header and .opencode/skills/canonical-header in your project.
What does Canonical Header need to run?
SKILL.md names no scripts, command-line tools or credentials: Canonical Header is instructions for the agent only.
Does Canonical Header access the network?
SKILL.md names 1 domain. As links in the text: frontendchecklist.io. This is read from the text; nothing was executed.
Is Canonical Header safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Canonical Header use?
Canonical Header is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Canonical Header use?
About 432 tokens (SKILL.md is roughly 1.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 637 tokens, read only when the agent opens those files.
What are the alternatives to Canonical Header?
Skills that share tags, products or a category with Canonical Header: GEO-First SEO Audit Tool (zubair-trabzada/geo-seo-claude, 11k stars), SEO Optimizer (ailabs-393/ai-labs-claude-skills, 455 stars), SEO and GEO Audit (dageno-agents/seo-geo-audit, 176 stars) and SEO Setup (alisamadiii/Portfolio, 180 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Canonical Header?
thedaviddias (a GitHub user) maintains it in thedaviddias/Front-End-Checklist, which has 74,421 GitHub stars. The repository holds 390 skills in this directory. The repository was last updated on October 6, 2026.
Source: thedaviddias/Front-End-Checklist on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.