Google SEO APIs
AgriciDaniel/claude-seo
Pulls real Google data for SEO work: Search Console, PageSpeed Insights, CrUX field data, the Indexing API and GA4 organic traffic, through /seo google commands.
When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals.
Install Canonical Tag
$ npx skills add kostja94/marketing-skills --skill canonical-tag -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install kostja94/marketing-skills canonical-tag --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/kostja94/marketing-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/seo/technical/canonical .claude/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .claude/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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/kostja94/marketing-skills/tree/main/skills/seo/technical/canonicalType 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 kostja94/marketing-skills --skill canonical-tag -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install kostja94/marketing-skills canonical-tag --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/seo/technical/canonical .agents/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .agents/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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 kostja94/marketing-skills --skill canonical-tag -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install kostja94/marketing-skills canonical-tag --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/seo/technical/canonical .cursor/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .cursor/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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/kostja94/marketing-skills.git --path skills/seo/technical/canonical--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 kostja94/marketing-skills --skill canonical-tag -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install kostja94/marketing-skills canonical-tag --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/seo/technical/canonical .gemini/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .gemini/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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 kostja94/marketing-skills canonical-tagInstalls 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 kostja94/marketing-skills --skill canonical-tag -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/seo/technical/canonical .github/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .github/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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 kostja94/marketing-skills --skill canonical-tag -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install kostja94/marketing-skills canonical-tag --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/seo/technical/canonical .opencode/skills/canonical-tag && 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-tag" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/canonical into .opencode/skills/canonical-tag/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "canonical-tag", 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-tag- GitHub stars
- 1k
- Token cost
- ~1.2k tokens
- SKILL.md length
- 450 words
- Files
- 1
- Skills in repo
- 102
- Repo updated
- First seen
- Licence
- MIT
At a glance
When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals.
- Works in 3 steps: Site URL: Base domain → Duplicate scenarios: Multi-language,… → Framework: Next.js, React, static, etc.
- Wants to configure canonical URLs
- SKILL.md covers Scope (Technical SEO), Initial Assessment, Canonicalization Methods… and HTTPS & Security, plus 6 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Canonical Tag is an agent skill from kostja94/marketing-skills. When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals. Also use when the user mentions "canonical," "canonical URL," "duplicate content," "duplicate content fix," "preferred URL," or "URL consolidation." For GSC duplicates, use google-search-console.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Marketing & SEO, covering Technical SEO. It works with Google Search Console. The repository describes itself as: Agent Skills for Marketing — SEO, Social, Influencer & More. 160+ open-source skills for SEO, content, 40+ page types, paid ads, channels, and strategies. Add project context… The licence is MIT.
When your agent uses it
- Wants to configure canonical URLs
- Fix duplicate content
- Consolidate URL signals
- The user mentions canonical
Example prompts
- “canonical,”
- “canonical URL,”
- “duplicate content,”
- “/canonical-tag”
Workflow steps
3 steps, taken from the first numbered list in SKILL.md.
- Site URL: Base domain
- Duplicate scenarios: Multi-language, query params, pagination, alternate URLs
- Framework: Next.js, React, static, etc.
What it can do on your machine
Read from SKILL.md and the folder at commit 8dd89c5. 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 (its code samples are typescript, html, apache and nginx).
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):
developers.google.comalignify.co
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 Tag loads about 1.2k tokens when it runs. Until then it costs about 77 tokens; SKILL.md has 450 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 kostja94/marketing-skills at commit 8dd89c5, republished under its MIT licence (© kostja94). 450 words, ~1,203 tokens.
Download SKILL.mdSave it as
.claude/skills/canonical-tag/SKILL.md (or your agent's skills folder).- name
- canonical-tag
- description
- When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals. Also use when the user mentions "canonical," "canonical URL," "duplicate content," "duplicate content fix," "preferred URL," or "URL consolidation." For GSC duplicates, use google-search-console.
- metadata.version
- 1.0.1
SEO Technical: Canonical
Guides canonical tag configuration to consolidate duplicate content and declare preferred URLs.
When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.
Scope (Technical SEO)
- Duplicate site versions: HTTPS vs HTTP; www vs non-www; trailing slash (/page vs /page/) — choose one, 301 redirect others
- Duplicate content: Canonical tags; consolidate and 301 to preferred URL
- HTTPS: SSL/TLS; secure connection; ranking signal since 2014
Initial Assessment
Project context: Read root contextus.md when present and load only the modules relevant to this task. Without Contextus, use available project material or user-provided facts and ask for missing information; do not create a parallel context system.
Identify:
- Site URL: Base domain
- Duplicate scenarios: Multi-language, query params, pagination, alternate URLs
- Framework: Next.js, React, static, etc.
Canonicalization Methods (Choose by Scenario)
| Method | When | Strength |
|---|---|---|
| 301 redirect | Preferred; server can redirect | Strongest — permanent redirect |
| Canonical tag | Cannot redirect (e.g. params, pagination) | Strong — HTML signal |
| robots.txt | Block non-canonical paths | Weak — advisory only |
Use 301 for HTTP→HTTPS, www variants, trailing slash. Use canonical for params, pagination, UTM.
HTTPS & Security
HTTPS is a ranking signal (Google, 2014). Users and crawlers should access only the HTTPS version.
| Requirement | Action |
|---|---|
| SSL/TLS certificate | Install valid certificate; use Let's Encrypt for free |
| 301 redirect | HTTP → HTTPS; all HTTP requests redirect to HTTPS |
| Mixed content | No HTTP resources on HTTPS pages; fix mixed content warnings |
| HSTS | Optional; Strict-Transport-Security header for repeat visitors |
WWW vs non-WWW: Choose one preferred version; 301 redirect the other. See canonical rules above.
Show full SKILL.md (172 more words)Show less
When to Use Canonical
- Multi-language: Each language version has its own canonical; use hreflang with canonical
- Same content, multiple URLs: Params, pagination, tracking params, www vs non-www, trailing slash (/page vs /page/)
- Self-referencing: Canonical should point to self or the preferred version
- Avoid chain canonical: A→B→C is invalid
Rules
| Rule | Note |
|---|---|
| Absolute URL | Include https:// |
| Consistency | Must match current page URL or the chosen preferred version |
| No chains | A→B→C is invalid |
Implementation Patterns
Next.js (metadata)
export const metadata = {
alternates: {
canonical: "https://example.com/page-slug",
languages: {
zh: "https://example.com/zh/page-slug",
en: "https://example.com/page-slug",
"x-default": "https://example.com/page-slug",
},
},
};HTML (generic)
<link rel="canonical" href="https://example.com/page-slug" />Server Redirects (301)
Apache (.htaccess):
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]Nginx:
return 301 https://$host$request_uri;Relationship to Other Technical SEO
- Sitemap: URLs in sitemap should match canonical
- IndexNow: Submit canonical URLs
Output Format
- Canonical URL for each page type
- Implementation (metadata or HTML)
- Multi-language setup if applicable
- References: Alignify URL optimization; Google Canonical
Related Skills
- url-structure: URL hierarchy and format; canonical handles duplicate variants (HTTPS, www, trailing slash)
- localization-strategy: hreflang + canonical for multi-language
- xml-sitemap: Sitemap URLs should match canonical
- indexnow: Submit canonical URLs
- google-search-console: Find duplicate content in Coverage report
- indexing: Resolve indexing issues
- site-crawlability: Crawl budget; redirect chains; canonical reduces duplicate crawl waste
© kostja94, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/seo/technical/canonical of kostja94/marketing-skills.
Open the folder on GitHubat commit 8dd89c5
Compare with similar skills
Canonical Tag 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 Tag this skillkostja94/marketing-skills | 1k | — | ~1.2k | Automated safety check: Pass | MIT | |
| Google SEO APIsAgriciDaniel/claude-seo | 19k | 1 repos | ~4.2k | Automated safety check: Pass | MIT | |
| SEO Coachakseolabs-seo/seo-coach | 146 | — | ~2.8k | Automated safety check: Pass | None | |
| SEO Setupalisamadiii/Portfolio | 180 | — | ~1.7k | Automated safety check: Pass | None | |
| Google Search SEO Guidelittleben/awesomeAgentskills | 189 | 2 repos | ~4.2k | Automated safety check: Pass | MIT | |
| SEO Googleseranking/seo-skills | 161 | — | ~4.8k | Automated safety check: Pass | MIT |
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Questions about Canonical Tag
What does Canonical Tag do?
When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals. Canonical Tag is an agent skill from kostja94/marketing-skills. When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals.
When should I use Canonical Tag?
Canonical Tag fits situations like: wants to configure canonical URLs; fix duplicate content; consolidate URL signals; the user mentions canonical.
How do I install Canonical Tag in Claude Code?
Run `npx skills add kostja94/marketing-skills --skill canonical-tag -a claude-code`. Or copy the skill folder (skills/seo/technical/canonical in kostja94/marketing-skills) into .claude/skills/canonical-tag in your project. Claude Code loads it when a task matches its description.
How do I install Canonical Tag in Codex?
Run `npx skills add kostja94/marketing-skills --skill canonical-tag -a codex`. Or copy the skill folder (skills/seo/technical/canonical in kostja94/marketing-skills) into .agents/skills/canonical-tag in your project. Codex loads it when a task matches its description.
Can I use Canonical Tag 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 kostja94/marketing-skills --skill canonical-tag -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-tag, .gemini/skills/canonical-tag, .github/skills/canonical-tag and .opencode/skills/canonical-tag in your project.
What does Canonical Tag need to run?
SKILL.md names no scripts, command-line tools or credentials: Canonical Tag is instructions for the agent only.
Does Canonical Tag access the network?
SKILL.md names 2 domains. As links in the text: developers.google.com and alignify.co. This is read from the text; nothing was executed.
Is Canonical Tag 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 Tag use?
Canonical Tag 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 Tag use?
About 1.2k tokens (SKILL.md is roughly 4.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Canonical Tag?
Skills that share tags, products or a category with Canonical Tag: Google SEO APIs (AgriciDaniel/claude-seo, 19k stars), SEO Coach (akseolabs-seo/seo-coach, 146 stars), SEO Setup (alisamadiii/Portfolio, 180 stars) and Google Search SEO Guide (littleben/awesomeAgentskills, 189 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Canonical Tag?
kostja94 (a GitHub user) maintains it in kostja94/marketing-skills, which has 1,025 GitHub stars. The repository holds 102 skills in this directory. The repository was last updated on October 6, 2026.
Source: kostja94/marketing-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.