Claude SEO is an open-source Claude Code plugin that runs specialized agents and skills to audit websites across technical SEO, content quality, structured data, AI-search optimization, local and e-commerce SEO, and international SEO. SEO practitioners use it to produce prioritized recommendations based on primary-source guidance, with optional extensions for external data and crawling.
Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add AgriciDaniel/claude-seo/plugin install claude-seoWrote 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/agricidaniel/claude-seo/seo-images)<a href="https://agentmods.dev/skills/agricidaniel/claude-seo/seo-images"><img src="https://agentmods.dev/badge/skills/agricidaniel/claude-seo/seo-images/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/agricidaniel/claude-seo/seo-images"><img src="https://agentmods.dev/badge/skills/agricidaniel/claude-seo/seo-images.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector warn
SkillSpector: 4 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Privilege Escalation · line 237 Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
- medium Privilege Escalation · line 238 Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
- medium Privilege Escalation · line 432 Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
- medium Privilege Escalation · line 433 Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
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 | $0.00108 | $0.04363 |
| Opus 5.5 | $0.00043 | $0.01745 |
| Sonnet 5.5 | $0.00022 | $0.00873 |
| Haiku 4.5 | $0.00011 | $0.00436 |
Grade A, and why
seo-images scanned grade A with 1 finding 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 5d 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.
Asks for rootlowPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
- `exiftool` -- EXIF/IPTC/XMP read/write (install: `sudo apt install libimage-exiftool-perl`) Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Copies of this mod
2 near-identical copies found in the catalogue:
- seo-images — 95% identical, 38 lines differ
- seo-images — 84% identical, 85 lines differ
How it starts
The opening of the file, as written. The whole thing — 445 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Image Optimization Analysis
Checks
Alt Text
- Present on all
<img>elements (except decorative:role="presentation") - Descriptive: describes the image content, not "image.jpg" or "photo"
- Includes relevant keywords where natural, not keyword-stuffed
- Length: 10-125 characters
Good examples:
- "Professional plumber repairing kitchen sink faucet"
- "Red 2024 Toyota Camry sedan front view"
- "Team meeting in modern office conference room"
Bad examples:
- "image.jpg" (filename, not description)
- "plumber plumbing plumber services" (keyword stuffing)
- "Click here" (not descriptive)
File Size
Tiered thresholds by image category:
| Image Category | Target | Warning | Critical |
|---|---|---|---|
| Thumbnails | < 50KB | > 100KB | > 200KB |
| Content images | < 100KB | > 200KB | > 500KB |
| Hero/banner images | < 200KB | > 300KB | > 700KB |
Recommend compression to target thresholds where possible without quality loss.
Format
| Format | Browser Support | Use Case |
|---|---|---|
| WebP | 97%+ | Default recommendation |
| AVIF | 92%+ | Best compression, newer |
| JPEG | 100% | Fallback for photos |
| PNG | 100% | Graphics with transparency |
| SVG | 100% | Icons, logos, illustrations |
Recommend WebP/AVIF over JPEG/PNG. Check for <picture> element with format fallbacks.
Recommended <picture> Element Pattern
Use progressive enhancement with the most efficient format first:
<picture>
<source srcset="image.avif" type="image/avif">
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Descriptive alt text" width="800" height="600" loading="lazy" decoding="async">
</picture>
The browser will use the first supported format. Global browser support (caniuse.com, checked 2026-09-28): AVIF about 95.4%, WebP about 96.8%. Re-check caniuse before quoting.
JPEG XL: Emerging Format
Third-party reporting and Wikipedia describe a Rust-based JPEG XL decoder as shipped in Chrome 145 stable (2026-02-10) behind the chrome://flags/#enable-jxl-image-format flag, not enabled by default; no Google-owned confirmation was retrieved in the fact pack. Because default support is not confirmed, it is not yet practical for production web delivery. Keep serving AVIF/WebP with JPEG fallback and monitor.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 5d ago Changed · +8 lines 3ae3b6b6338d
- 23d ago Changed 51afe540d638
- 28d ago Changed c13406c20671
- 1mo ago Changed · +2 lines 700cfc5176b0
- 1mo ago Changed 3a8d61c3a1ae
- 1mo ago First seen · 435 lines · 108 tokens per session scan A 00c1e22f2d82
seo-images is a skill published in the GitHub repository AgriciDaniel/claude-seo (22,763 stars, last pushed 5d ago), licensed MIT. It adds 108 tokens to every session and 4,363 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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