browser

A browser-automation workflow that delegates browser tasks to a separate agent and returns concise summaries. Browser automation means operating websites programmatically, such as clicking, typing, and reading pages.

In plain words
What is it for?
Use it to test pages, capture screenshots, fill forms, extract page content, navigate websites, automate workflows, or check whether a site is working.
Why use it?
It keeps browser interactions organized while covering testing, form entry, data extraction, workflow automation, and troubleshooting tasks.

Skill for Claude CodeCodex

Part of the kas plugin — 1 skill, 9 commands, 4 agents shipped together

Install

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.

agentmods
npx agentmods add skills/kastheco/claude-plugins/browser
Any agent
npx skills add kastheco/claude-plugins --skill browser
Clone the repo
git clone --depth 1 https://github.com/kastheco/claude-plugins

Made for: Claude Code, Codex.

Or install kas, the plugin that ships this one along with the rest of its 1 skill, 9 commands, 4 agents.

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 938 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00938
Opus 5 $0.00000 $0.00469
Sonnet 5 $0.00000 $0.00188
Haiku 4.5 $0.00000 $0.00094

Measured 2d ago against content hash c72143146298, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

browser 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 2d 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.

plugins/kas/skills/browser/SKILL.md · 160 lines

How it starts

The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Browser Automation Skill

This skill handles browser automation tasks using subagent architecture to keep the main context window clean.

Core Principle

NEVER call Claude-in-Chrome MCP tools directly in main context.

All browser automation is delegated to the browser-automation Task subagent which returns concise summaries.

Detection Triggers

Activate this skill when detecting:

Web Testing

  • "test the website", "check the page", "verify the UI"
  • "screenshot", "capture the screen", "take a picture"
  • "does the site work", "is the page loading"

Form Automation

  • "fill out the form", "submit this form", "enter data"
  • "sign up", "register", "create account" (with explicit user permission)
  • "login", "authenticate" (without entering passwords directly)

Data Extraction

  • "scrape this page", "extract data from", "get the text"
  • "what's on the page", "read the content", "parse the data"
  • "find the price", "get the title", "extract the links"

Workflow Automation

  • "automate this workflow", "record these steps", "create a GIF"
  • "click through", "navigate to", "go to page"
  • "test the flow", "verify the process"

Debugging & Monitoring

  • "check console logs", "monitor network requests", "debug the page"
  • "why is this failing", "what's the error", "inspect the page"

Subagent Delegation Pattern

When a browser automation task is detected:

Task("Browser: {brief_description}

**Task:** {user_request}
**URL:** {target_url if provided}
**Actions:** {list of expected actions}

Using Claude-in-Chrome MCP tools:
1. Start with tabs_context_mcp to get current tab state
2. Create new tab or use existing based on context
3. Navigate, interact, extract data as needed
4. Capture screenshots/GIFs for multi-step workflows
5. Monitor console/network if debugging

Return ONLY a concise summary:
- Actions taken (e.g., "Navigated to X, filled form, clicked submit")
- Key findings (e.g., "Form submitted successfully", "Error: XYZ")
- Screenshots/visual evidence if captured
- Any errors or unexpected behavior

Do NOT include:
- Raw HTML or page source
- Verbose console logs (use pattern filtering)
- Detailed network request payloads
- Implementation details

subagent_type: browser-automation
")

Read the full file on GitHub · 160 lines

Changes

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.

  1. 2d ago First seen · 160 lines · 0 tokens per session scan A c72143146298

Subscribe to this mod's changes

browser is a skill published in the GitHub repository kastheco/claude-plugins (2 stars, last pushed 4mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 938 tokens. 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 2026-08-31.

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