Browser4 is an AI-native browser engine that lets autonomous agents and people control real browsers, extract information from web pages, and automate tasks at scale. It combines browser interaction through a Rust CLI and MCP with deterministic selectors, machine-learning clustering, and language-model extraction. The catalogue entries provide skills and instructions for using Browser4.
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 platonai/Browser4 --skill web-scrapinggit clone --depth 1 https://github.com/platonai/Browser4Wrote 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/platonai/browser4/web-scraping)<a href="https://agentmods.dev/skills/platonai/browser4/web-scraping"><img src="https://agentmods.dev/badge/skills/platonai/browser4/web-scraping/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/platonai/browser4/web-scraping"><img src="https://agentmods.dev/badge/skills/platonai/browser4/web-scraping.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 | $0.00048 | $0.00999 |
| Opus 5.5 | $0.00019 | $0.00400 |
| Sonnet 5.5 | $0.00010 | $0.00200 |
| Haiku 4.5 | $0.00005 | $0.00100 |
Grade A, and why
web-scraping 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 24d 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.
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.
Web Scraping Skill
Description
Extract data from web pages using JavaScript and CSS selectors. This skill uses real browser automation to navigate to pages and extract content using JavaScript execution. It can extract webpage titles using document.title and body text using document.body.textContent, providing actual content from live web pages.
Dependencies
None
Parameters
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
| url | String | Yes | - | The URL of the web page to scrape |
| selector | String | Yes | - | CSS selector to target specific elements |
| attributes | List | No | ["text"] | List of attributes to extract (e.g., "text", "href", "src") |
Return Value
Returns a SkillResult with the following data structure:
{
"url": "string",
"selector": "string",
"attributes": ["string"],
"data": "extracted content"
}
Usage Examples
Basic Text Extraction
val result = registry.execute(
skillId = "web-scraping",
context = context,
params = mapOf(
"url" to "https://example.com",
"selector" to ".content"
)
)
Extract Multiple Attributes
val result = registry.execute(
skillId = "web-scraping",
context = context,
params = mapOf(
"url" to "https://example.com/products",
"selector" to "a.product-link",
"attributes" to listOf("text", "href")
)
)
Tool Call Specification
ToolSpec(
domain = "skill.debug.scraping",
method = "extract",
arguments = [
"url: String",
"selector: String",
"attributes: List<String> = listOf('text')"
],
returnType = "Map<String, Any>",
description = "Extract data from a web page using CSS selectors"
)
Error Handling
The skill returns a failure result in the following cases:
- Missing required parameter
url - Missing required parameter
selector - Invalid URL format (must start with http:// or https://)
What ships with it
4 files 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.
- 24d ago Changed 662274e5d2e2
- 1mo ago Changed bafc089ddf4e
- 1mo ago First seen · 125 lines · 48 tokens per session scan A 4061d16de8b7
web-scraping is a skill published in the GitHub repository platonai/Browser4 (1,161 stars, last pushed yesterday), licensed Apache-2.0. It adds 48 tokens to every session and 999 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-30.
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