dev-browser

A browser-automation and web-scraping skill that keeps page state while it navigates websites and interacts with web apps.

In plain words
What is it for?
It is for opening websites, clicking elements, filling forms, taking screenshots, extracting web data, and testing or automating web applications.
Why use it?
It removes the need to perform repeated browser actions by hand when collecting data, testing pages, or completing forms.

Skill for Claude CodeCodex

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

Made for: Claude Code, Codex.

Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,517 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 $0.00086 $0.01517
Opus 5 $0.00043 $0.00758
Sonnet 5 $0.00017 $0.00303
Haiku 4.5 $0.00009 $0.00152

Measured 2d ago against content hash 90bfa936fd61, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dev-browser 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 2d ago.

The scan reads SKILL.md. This mod also ships 12 executable files (scripts/start-relay.ts, scripts/start-server.ts, server.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

curl -s http://localhost:9222 > /dev/null 2>&1 && echo "Server ready" && break
dev-browser/skills/dev-browser/SKILL.md · 190 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 190 lines · 86 tokens per session scan A 90bfa936fd61

Subscribe to this mod's changes

dev-browser is a skill published in the GitHub repository grailautomation/claude-plugins (2 stars, last pushed 2mo ago), with no licence file. It adds 86 tokens to every session and 1,517 once invoked, about $0.0004 per session on Opus 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.

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