Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add kostja94/marketing-skills --skill canonicalgit clone --depth 1 https://github.com/kostja94/marketing-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/kostja94/marketing-skills/canonical)<a href="https://agentmods.dev/skills/kostja94/marketing-skills/canonical"><img src="https://agentmods.dev/badge/skills/kostja94/marketing-skills/canonical/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/kostja94/marketing-skills/canonical"><img src="https://agentmods.dev/badge/skills/kostja94/marketing-skills/canonical.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00062 | $0.01133 |
| Opus 5 | $0.00031 | $0.00566 |
| Sonnet 5 | $0.00012 | $0.00227 |
| Haiku 4.5 | $0.00006 | $0.00113 |
Grade A, and why
canonical-tag scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
2 near-identical copies found in the catalogue:
- canonical-tag — 100% identical, 0 lines differ
- canonical-tag — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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
Check for project context first: If .claude/project-context.md or .cursor/project-context.md exists, read it for site URL and language structure.
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 |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 125 lines · 62 tokens per session scan A a8490032085c
canonical-tag is a skill published in the GitHub repository kostja94/marketing-skills (967 stars, last pushed 3mo ago), licensed MIT. It adds 62 tokens to every session and 1,133 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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