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 PavloSEO/seohead-seotools --skill js-render-checkgit clone --depth 1 https://github.com/PavloSEO/seohead-seotoolsWrote 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/pavloseo/seohead-seotools/js-render-check)<a href="https://agentmods.dev/skills/pavloseo/seohead-seotools/js-render-check"><img src="https://agentmods.dev/badge/skills/pavloseo/seohead-seotools/js-render-check/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/pavloseo/seohead-seotools/js-render-check"><img src="https://agentmods.dev/badge/skills/pavloseo/seohead-seotools/js-render-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00153 | $0.01161 |
| Opus 5.5 | $0.00061 | $0.00464 |
| Sonnet 5.5 | $0.00031 | $0.00232 |
| Haiku 4.5 | $0.00015 | $0.00116 |
Grade A, and why
js-render-check 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 2mo 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
**One command instead of manually using curl and headless Chrome:** How it starts
The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.
JS Render Check — What Is Visible on the Page Only After JavaScript
Screaming Frog measures one snapshot—raw or rendered, depending on whether JS Rendering is enabled—but does not compare "before JS" with "after JS." This skill performs exactly that diff.
When to Use It
- "Do content / links / metadata appear only after JS?"
- SPA / Next.js / Nuxt / CSR: "Will it be indexed?" or "Is SSR required?"
- An SF crawl differs with JS Rendering enabled versus disabled, and you need to determine which count is correct.
- A regional or silo audit found zero links where links are known to exist.
Workflow
One command instead of manually using curl and headless Chrome:
seohead render-check --url https://example.com
Use a mobile viewport and device emulation where the layout differs:
seohead render-check --url https://example.com --viewport mobile
Returned fields:
| Field | Meaning |
|---|---|
raw / rendered |
identically calculated snapshots of both documents: words, internal links, title, h1, canonical, JSON-LD types, and size |
empty_shell |
ID of an empty single-page application container, if present |
js_dependent |
whether the page depends on scripts in any way |
metrics_lab |
TTFB, FCP, LCP, CLS, load, and weight—lab data, not field data |
findings |
ready-to-use written conclusions |
How to Interpret Findings
| Finding | Severity | Action |
|---|---|---|
"empty <div id="root"> container" |
critical | use SSR or prerendering: without rendering, the bot sees an empty page |
| "N% of text appears only after JS" | critical when >50% | move the primary content into the server response |
| "links appear only after JS" | critical | site traversal breaks: the crawler cannot reach deeper pages |
| "title is changed by a script" | critical | an unpredictable title may appear in search results |
| "canonical is injected by a script" | critical | the directive must not depend on rendering |
| "Schema.org appears only after JS" | warning | rich results are uncertain |
| "rendering changes nothing" | okay | SSR works; no further investigation is needed |
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.
- 2mo ago First seen · 96 lines · 153 tokens per session scan A 6d90a14616bc
js-render-check is a skill published in the GitHub repository PavloSEO/seohead-seotools (0 stars, last pushed 2mo ago), licensed MIT. It adds 153 tokens to every session and 1,161 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
js-render-check compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| js-render-checkPavloSEO/seohead-seotools | Skill | 0 | 2mo ago | MIT | A | 153 | Claude Code |
| computer-useperasyudha/Nyxora | Skill | 5 | 9d ago | MIT | A | 68 | Claude Code, Codex |
| dogfoodperasyudha/Nyxora | Skill | 5 | 9d ago | MIT | A | 18 | Claude Code, Codex |
| broken-link-checkernowork-studio/notfair-plugin | Skill | 4.1k | 2d ago | MIT | A | 70 | Claude Code |
| tempsgotempsh/temps | Skill | 904 | today | Apache-2.0 | A | 157 | Codex |
| research-keywordsonvoyage-ai/gtm-engineer-skills | Skill | 1.4k | 27d ago | MIT | A | 46 | Claude Code, Codex |
| geo-content-planningonvoyage-ai/gtm-engineer-skills | Skill | 1.4k | 27d ago | MIT | A | 52 | Claude Code, Codex |